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• Microsoft Office Basic Edition 2003

  - by Carole

  How do I copy custom dictionary on word 2000 onto a flash drive and then copy it to custom dictionary word 2003 on my new computer?

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• Suddenly unable to export to war file from exclipse

  - by Codeguy007

  I been working on this Servlet project all morning and now suddenly I cannot get eclipse to export the project to a war file. I tried restarting eclipse and cleaning the project but I just get the same result. Any ideas? org.eclipse.core.runtime.CoreException: Extended Operation failure: org.eclipse.jst.j2ee.internal.web.archive.operations.WebComponentExportOperation at org.eclipse.wst.common.frameworks.internal.datamodel.ui.DataModelWizard.performFinish(DataModelWizard.java:182) at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:742) at org.eclipse.jface.wizard.WizardDialog.buttonPressed(WizardDialog.java:373) at org.eclipse.jface.dialogs.Dialog$2.widgetSelected(Dialog.java:618) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:227) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:938) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3682) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3293) at org.eclipse.jface.window.Window.runEventLoop(Window.java:820) at org.eclipse.jface.window.Window.open(Window.java:796) at org.eclipse.ui.actions.ExportResourcesAction.run(ExportResourcesAction.java:180) at org.eclipse.ui.actions.BaseSelectionListenerAction.runWithEvent(BaseSelectionListenerAction.java:168) at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:546) at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:490) at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:402) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:938) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3682) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3293) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2389) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2353) at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2219) at org.eclipse.ui.internal.Workbench$4.run(Workbench.java:466) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:289) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:461) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:106) at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:169) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:106) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:76) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:363) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:176) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:508) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:447) at org.eclipse.equinox.launcher.Main.run(Main.java:1173) org.eclipse.core.runtime.CoreException[0]: org.eclipse.core.commands.ExecutionException: Error exportingWar File at org.eclipse.jst.j2ee.internal.archive.operations.J2EEArtifactExportOperation.execute(J2EEArtifactExportOperation.java:103) at org.eclipse.wst.common.frameworks.internal.datamodel.DataModelPausibleOperationImpl$1.run(DataModelPausibleOperationImpl.java:376) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:1797) at org.eclipse.wst.common.frameworks.internal.datamodel.DataModelPausibleOperationImpl.runOperation(DataModelPausibleOperationImpl.java:401) at org.eclipse.wst.common.frameworks.internal.datamodel.DataModelPausibleOperationImpl.runOperation(DataModelPausibleOperationImpl.java:352) at org.eclipse.wst.common.frameworks.internal.datamodel.DataModelPausibleOperationImpl.doExecute(DataModelPausibleOperationImpl.java:242) at org.eclipse.wst.common.frameworks.internal.datamodel.DataModelPausibleOperationImpl.executeImpl(DataModelPausibleOperationImpl.java:214) at org.eclipse.wst.common.frameworks.internal.datamodel.DataModelPausibleOperationImpl.cacheThreadAndContinue(DataModelPausibleOperationImpl.java:89) at org.eclipse.wst.common.frameworks.internal.datamodel.DataModelPausibleOperationImpl.execute(DataModelPausibleOperationImpl.java:202) at org.eclipse.wst.common.frameworks.internal.datamodel.ui.DataModelWizard$1$CatchThrowableRunnableWithProgress.run(DataModelWizard.java:211) at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:113) Caused by: org.eclipse.jst.j2ee.commonarchivecore.internal.exception.SaveFailureException: IWAE0017E Unable to replace original archive: C:\Users\mark\uploads\myfirstjsp.war at org.eclipse.jst.j2ee.commonarchivecore.internal.impl.ArchiveImpl.cleanupAfterTempSave(ArchiveImpl.java:322) at org.eclipse.jst.j2ee.commonarchivecore.internal.impl.ArchiveImpl.saveAsNoReopen(ArchiveImpl.java:1182) at org.eclipse.jst.j2ee.internal.web.archive.operations.WebComponentExportOperation.export(WebComponentExportOperation.java:54) at org.eclipse.jst.j2ee.internal.archive.operations.J2EEArtifactExportOperation.execute(J2EEArtifactExportOperation.java:95) ... 10 more

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• Interactive Data Language, IDL: Does anybody care?

  - by Alex

  Anyone use a language called Interactive Data Language, IDL? It is popular with scientists. I think it is a poor language because it is proprietary (every terminal running it has to have an expensive license purchased) and it has minimal support (try searching for IDL, the language, right now on stack) . I am trying to convince my colleagues to stop using it and learn C/C++/Python/Fortran/Java/Ruby. Does anybody know about or even care about IDL enough to have opinions on it? What do you think of it? Should I tell my colleagues to stop wasting their time on it now? How can I convince them? Edit: People are getting the impression that I don't know or use IDL. Also, I said IDL has minimal support which is true in one sense, so I must clarify that the scientific libraries are indeed large. I use IDL all the time, but this is exactly the problem: I am only using IDL because colleagues use it. There is a file format IDL uses, the .sav, which can only be opened in IDL. So I must use IDL to work with this data and transfer the data back to colleagues, but I know I would be more efficient in another language. This is like someone sending you a microsoft word file in an email attachment and if you don't understand how wrong that is then you probably write too many words not enough code and you bought microsoft word. Edit: As an alternative to IDL Python is popular. Here is a list of The Pros of IDL (and the cons) from AstroBetter: Pros of IDL Mature many numerical and astronomical libraries available Wide astronomical user base Numerical aspect well integrated with language itself Many local users with deep experience Faster for small arrays Easier installation Good, unified documentation Standard GUI run/debug tool (IDLDE) Single widget system (no angst about which to choose or learn) SAVE/RESTORE capability Use of keyword arguments as flags more convenient Cons of IDL Narrow applicability, not well suited to general programming Slower for large arrays Array functionality less powerful Table support poor Limited ability to extend using C or Fortran, such extensions hard to distribute and support Expensive, sometimes problem collaborating with others that don’t have or can’t afford licenses. Closed source (only RSI can fix bugs) Very awkward to integrate with IRAF tasks Memory management more awkward Single widget system (useless if working within another framework) Plotting: Awkward support for symbols and math text Many font systems, portability issues (v5.1 alleviates somewhat) not as flexible or as extensible plot windows not intrinsically interactive (e.g., pan & zoom) Pros of Python Very general and powerful programming language, yet easy to learn. Strong, but optional, Object Oriented programming support Very large user and developer community, very extensive and broad library base Very extensible with C, C++, or Fortran, portable distribution mechanisms available Free; non-restrictive license; Open Source Becoming the standard scripting language for astronomy Easy to use with IRAF tasks Basis of STScI application efforts More general array capabilities Faster for large arrays, better support for memory mapping Many books and on-line documentation resources available (for the language and its libraries) Better support for table structures Plotting framework (matplotlib) more extensible and general Better font support and portability (only one way to do it too) Usable within many windowing frameworks (GTK, Tk, WX, Qt…) Standard plotting functionality independent of framework used plots are embeddable within other GUIs more powerful image handling (multiple simultaneous LUTS, optional resampling/rescaling, alpha blending, etc) Support for many widget systems Strong local influence over capabilities being developed for Python Cons of Python More items to install separately Not as well accepted in astronomical community (but support clearly growing) Scientific libraries not as mature: Documentation not as complete, not as unified Not as deep in astronomical libraries and utilities Not all IDL numerical library functions have corresponding functionality in Python Some numeric constructs not quite as consistent with language (or slightly less convenient than IDL) Array indexing convention “backwards” Small array performance slower No standard GUI run/debug tool Support for many widget systems (angst regarding which to choose) Current lack of function equivalent to SAVE/RESTORE in IDL matplotlib does not yet have equivalents for all IDL 2-D plotting capability (e.g., surface plots) Use of keyword arguments used as flags less convenient Plotting: comparatively immature, still much development going on missing some plot type (e.g., surface) 3-d capability requires VTK (though matplotlib has some basic 3-d capability)

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• Is JQuery UI meant to work only with Google Chrome??? (How about IE and Firefox??!)

  - by Richard77

  Hello, I'm using "Jquery UI 1./Dan Wellman/Packt Publishing" to learn JQuery UI. I'm working on the 'Dialog widget' chapiter. After I've completed a series of exercises in order to build a Dialog widget (using Google Chrome), I then tried my work with Internet Explorer and Firefox. The result has been disappointing. Chrome was perfet With Internet Explorer, (1) the title of the Dialog widget did not appear, (2) The location of the dialog widget was not correct (given the position: ["center", "center"]). It was rather offset toward left. With Firefox, the location was respected. However, only the outer container was visible. the content was missing, just a blank container. Also using Option Show:true and Hide:true did only work with Chrome. I wonder now if JQuery UI was meant to be used only with Google Chrome. I just think that I might be missing some directives to make it work with major browsers (as the author claimed in his book). Here's the code. Since, I'm using ASP.NET MVC, certain codes, such as the element to the css, do not appear. But, for the rest, all the functioning code is bellow. <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <p> The goal of this tutorial is to explain one method of creating model classes for an ASP.NET MVC application. In this tutorial, you learn how to build model classes and perform database access by taking advantage of Microsoft LINQ to SQL. In this tutorial, we build a basic Movie database application. We start by creating the Movie database application in the fastest and easiest way possible. We perform all of our data access directly from our controller actions. </p> <div style = "font-size:.7em" id = "myDialog" title = "This is the title"> In this tutorial -- in order to illustrate how you can build model classes -- we build a simple Movie database application. The first step is to create a new database. Right-click the App_Data folder in the Solution Explorer window and select the menu option Add, New Item. Select the SQL Server Database template, give it the name MoviesDB.mdf, and click the Add button (see Figure 1). </div> </asp:Content> <asp:Content ID="Content3" ContentPlaceHolderID="ScriptContent" runat="server"> <script src="../../Content/development-bundle/jquery-1.3.2.js" type="text/javascript"></script> <script src="../../Content/development-bundle/ui/ui.core.js" type="text/javascript"></script> <script src="../../Content/development-bundle/ui/ui.dialog.js" type="text/javascript"></script> <script src="../../Content/development-bundle/ui/ui.draggable.js" type="text/javascript"></script> <script src="../../Content/development-bundle/ui/ui.resizable.js" type="text/javascript"></script> <script src="../../Content/development-bundle/external/bgiframe/jquery.bgiframe.js" type="text/javascript"></script> <script type = "text/javascript"> $(function() { var execute = function() { } var cancel = function() { } var dialogOpts = { position: ["center", "center"], title: '<a href="/Home/About">A link title!<a>', modal: true, minWidth: 500, minHeight: 500, buttons: { "OK": execute, "Cancel": cancel }, show:true, hide: true, bgiframe:true }; $("#myDialog").dialog(dialogOpts); }); </script> Thank for helping.

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• How to add the coding for displaying the address when a particular set of latitude and longitude is

  - by KKC

  import com.google.android.maps.GeoPoint; import com.google.android.maps.MapActivity; import com.google.android.maps.MapController; import com.google.android.maps.MapView; import android.os.Bundle; import android.view.KeyEvent; import android.view.View; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Spinner; import android.widget.AdapterView.OnItemSelectedListener; public class PopularAttractions extends MapActivity { private String[ ][ ] locations = { {"Singapore Zoological Garden","1.40502,103.793449"}, {"Singapore Night Safari","1.4037,103.789467"}, {"Jurong BirdPark","1.32005,103.707153"}, {"Jurong Reptile Park","1.321177,103.708486"}, {"Singapore Botanic Garden","1.31471,103.815689"}, {"Sungei Buloh Wetland Reserver","1.445144,103.729595"}, {"Escape Theme Park","1.38104,103.936928"}, {"Snow City","1.32823,103.74263"}, {"Super Ice World","1.300422,103.875348"}, {"Chinatown Heritage Center","1.2836,103.84425"}, {"Singapore Science Center","1.3249,103.740578"}, {"Red Dot Design Museum","1.277762,103.846225"}, {"G-Max Reverse Bungy","1.2906,103.845322"}, {"NEWater Visitor Center","1.33105,103.955311"} }; private Spinner spinnerView; private MapView mapView; private MapController mc; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); spinnerView = (Spinner) this.findViewById(R.id.spinner1); mapView = (MapView) findViewById(R.id.mapview1); mc = mapView.getController(); ArrayAdapter<CharSequence> adapter = new ArrayAdapter<CharSequence>(this, android.R.layout.simple_spinner_dropdown_item); //--add the various locations--- for(int i = 0; i < locations.length; i++) adapter.add(locations[i][0]); adapter.setDropDownViewResource( android.R.layout.simple_spinner_dropdown_item); spinnerView.setAdapter(adapter); spinnerView.setOnItemSelectedListener(selectListener); gotoSelected(); } //---when user selects an item--- private OnItemSelectedListener selectListener = new OnItemSelectedListener() { //---these are two methods you need to implement--- public void onItemSelected( AdapterView<?>parent, View v, int position, long id) { gotoSelected(); } public void onNothingSelected(AdapterView<?> arg0) {} }; //---when an item has been selected--- public void gotoSelected() { int index = spinnerView.getSelectedItemPosition(); String[] coordinates = locations[index][1].split(","); double lat = Double.parseDouble(coordinates[0]); double lng = Double.parseDouble(coordinates[1]); GeoPoint location = new GeoPoint ( (int)(lat * 1E6), (int)(lng * 1E6)); mc.animateTo(location); mc.setZoom(16); if (mapView.isSatellite()) mapView.setSatellite(false); else mapView.setStreetView(true); mapView.invalidate(); } public boolean onKeyDown(int keyCode, KeyEvent event) { MapController mc = mapView.getController(); switch (keyCode) { case KeyEvent.KEYCODE_3: mc.zoomIn(); break; case KeyEvent.KEYCODE_1: mc.zoomOut(); break; } return super.onKeyDown(keyCode, event); } @Override protected boolean isRouteDisplayed(){ //TODO Auto-generated method sub return false; } }

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• How to get Media Picker Field via proxy record of many-to-many in orchard

  - by Sergey Schipanov

  I need to access mediapickerfield in Widget view. This field is relative to 'ActionPart'. I have a problem, when I create many-to-many relationships to display my 'ActionPart' in the widget. When I mapped many-to-many I take an 'ActionPart' and but cannot access the mediapickerfield. Records classes public class ActionPartRecord : ContentPartRecord { public virtual string Text { get; set; } public virtual double Price { get; set; } public virtual int TextPosX { get; set; } public virtual int TextPosY { get; set; } public virtual String TextSale { get; set; } public virtual int Color { get; set; } } public class ActionListRecord { public virtual int Id { get; set; } public virtual ActionPartRecord ActionPartRecord { get; set; } public virtual ActionWidgetPartRecord ActionWidgetPartRecord { get; set; } } public class ActionWidgetPartRecord : ContentPartRecord { public ActionWidgetPartRecord() { ActionList = new List<ActionListRecord>(); } public virtual IList<ActionListRecord> ActionList { get; set; } } public class ActionWidgetPart : ContentPart<ActionWidgetPartRecord> { public IEnumerable<ActionPartRecord> ActionList { get { return Record.ActionList.Select(x => x.ActionPartRecord); } } } ActionPart class public class ActionPart : ContentPart<ActionPartRecord> { public String Text { get { return Record.Text; } set { Record.Text = value; } } /*other field*/ } Migrations public int Create() { SchemaBuilder.CreateTable("ActionPartRecord", table => table .ContentPartRecord() .Column<string>("Text") .Column<double>("Price") .Column<int>("TextPosX") .Column<int>("TextPosY") .Column<string>("TextSale") .Column<int>("Color") ); ContentDefinitionManager.AlterPartDefinition("ActionPart", builder => builder .WithField("BaseImage", fieldBuilder => fieldBuilder.OfType("MediaPickerField").WithDisplayName("Action Image")) .WithField("PatternImage", fieldBuilder => fieldBuilder.OfType("MediaPickerField").WithDisplayName("Pattern Image")) .WithField("TimeExp", fieldBuilder => fieldBuilder.OfType("DateTimeField").WithDisplayName("Expecting date")) .Attachable()); ContentDefinitionManager.AlterTypeDefinition("Action", cfg => cfg .WithPart("CommonPart") .WithPart("TitlePart") .WithPart("RoutePart") .WithPart("BodyPart") .WithPart("ActionPart") .Creatable() .Indexed()); SchemaBuilder.CreateTable("ActionListRecord", table => table .Column<int>("Id", column => column.PrimaryKey().Identity()) .Column<int>("ActionPartRecord_Id") .Column<int>("ActionWidgetPartRecord_Id") ); SchemaBuilder.CreateTable("ActionWidgetPartRecord", table => table .ContentPartRecord() ); ContentDefinitionManager.AlterPartDefinition( "ActionWidgetPart", builder => builder.Attachable()); ContentDefinitionManager.AlterTypeDefinition("ActionWidget", cfg => cfg .WithPart("ActionWidgetPart") .WithPart("WidgetPart") .WithPart("CommonPart") .WithSetting("Stereotype", "Widget")); return 1; } Driver Display method protected override DriverResult Display( ActionWidgetPart part, string displayType, dynamic shapeHelper) { return ContentShape("Parts_ActionWidget", () => shapeHelper.Parts_ActionWidget( ContentPart: part, ActionList: part.ActionList)); } Widget View @foreach (var action in Model.ActionList) { <div class="item"> *How to access BaseImage Field in this row* <div class="sale-pattern"></div> <div class="container"> <div class="carousel-caption"> <h1>@action.Text</h1> <h1 class="price">@action.Price</h1> </div> </div> </div> }

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• How to get the value of an item from database and set it as the spinner value

  - by kulPrins

  I have a database and the database populates a listview. when i long press a list item from the listview i get a context menu where i have the option to edit. When the edit option is clicked i open an activity and get all the values of the respective fields from the database. Now, here I want to get a value from the database and show it in the spinner. the spinner already has these values and is getting populated from the database... I have tried the following, but i get an error saying I can't cast a SimpleCursorAdapter to an ArrayAdapter.. String osub = cursor.getString(Database.INDEX_SUBJECT); Cursor cs = mDBS.querySub(osub); String subs = cs.getString(DatabaseSub.INDEX_SSUBJECT); if(cs!=null){ ArrayAdapter<String> myAdap = (ArrayAdapter<String>) subSpinner.getAdapter(); //cast to an ArrayAdapter int spinnerPosition = myAdap.getPosition(subs); //set the default according to value subSpinner.setSelection(spinnerPosition); Please tell me how to do this.. Thank you.. I am relatively new so please let me know if I am overlooking something. Thanks.. EDIT querySub method public Cursor querySub(String sub) throws SQLException { Cursor cursor = mDatabase.query(true, DATABASE_TABLE, sAllColumns, "ssub like " + "'" + sub + "'", null, null, null, null, null); if (cursor.moveToNext()) { return cursor; } cursor.moveToFirst(); return cursor; } Error Log 06-05 12:11:14.144: E/AndroidRuntime(775): FATAL EXCEPTION: main 06-05 12:11:14.144: E/AndroidRuntime(775): java.lang.RuntimeException: Unable to start activity ComponentInfo{an.droid.kit/an.droid.kit.DetailsActivity}: java.lang.ClassCastException: android.widget.SimpleCursorAdapter cannot be cast to android.widget.ArrayAdapter 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.ActivityThread.access$600(ActivityThread.java:123) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.os.Handler.dispatchMessage(Handler.java:99) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.os.Looper.loop(Looper.java:137) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.ActivityThread.main(ActivityThread.java:4424) 06-05 12:11:14.144: E/AndroidRuntime(775): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 12:11:14.144: E/AndroidRuntime(775): at java.lang.reflect.Method.invoke(Method.java:511) 06-05 12:11:14.144: E/AndroidRuntime(775): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 06-05 12:11:14.144: E/AndroidRuntime(775): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 06-05 12:11:14.144: E/AndroidRuntime(775): at dalvik.system.NativeStart.main(Native Method) 06-05 12:11:14.144: E/AndroidRuntime(775): Caused by: java.lang.ClassCastException: android.widget.SimpleCursorAdapter cannot be cast to android.widget.ArrayAdapter 06-05 12:11:14.144: E/AndroidRuntime(775): at an.droid.kit.DetailsActivity.dbToUI(DetailsActivity.java:217) 06-05 12:11:14.144: E/AndroidRuntime(775): at an.droid.kit.DetailsActivity.onCreate(DetailsActivity.java:104) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.Activity.performCreate(Activity.java:4465) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 06-05 12:11:14.144: E/AndroidRuntime(775): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920) 06-05 12:11:14.144: E/AndroidRuntime(775): ... 11 more

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• sherlock actionbar menu

  - by user1647443

  I am trying to setup a menu programatically and my method gets com.actionbarsherlock.view.Menu menu as a parameter. As I want to change the styling of the menu item I am trying to setup a SpannableString spannable and pass it to add. menu.add(0, MENU_ABOUT, 0, spannable); This is causing a crash only in ICS when I cick that menu item. Any ideas if I am missing something. Thanks Here is the code I am trying and it crashes when I run the app and select "About Application". FYI, I am using SpannableString because I want to add some styling and color to the menu item. The crash does NOT happen if I use a regular string, but then I cant do styling public boolean onCreateOptionsMenu(com.actionbarsherlock.view.Menu menu) { SpannableString spannable = new SpannableString("About Application"); menu.add(0, MENU_ABOUT, 0, spannable); return true; } Here is the stack trace: 09-05 02:25:32.849: E/AndroidRuntime(684): FATAL EXCEPTION: main 09-05 02:25:32.849: E/AndroidRuntime(684): java.lang.IllegalArgumentException: Invalid payload item type 09-05 02:25:32.849: E/AndroidRuntime(684): at android.util.EventLog.writeEvent(Native Method) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.app.Activity.onMenuItemSelected(Activity.java:2501) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:351) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:950) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.ListMenuPresenter.onItemClick(ListMenuPresenter.java:163) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AdapterView.performItemClick(AdapterView.java:292) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView.performItemClick(AbsListView.java:1058) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView.onTouchEvent(AbsListView.java:3180) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.View.dispatchTouchEvent(View.java:5541) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1951) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1712) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1726) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1860) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.View.dispatchPointerEvent(View.java:5721) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:2890) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2466) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.processInputEvents(ViewRootImpl.java:845) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2475) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.os.Handler.dispatchMessage(Handler.java:99) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.os.Looper.loop(Looper.java:137) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.app.ActivityThread.main(ActivityThread.java:4424) 09-05 02:25:32.849: E/AndroidRuntime(684): at java.lang.reflect.Method.invokeNative(Native Method) 09-05 02:25:32.849: E/AndroidRuntime(684): at java.lang.reflect.Method.invoke(Method.java:511) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 09-05 02:25:32.849: E/AndroidRuntime(684): at dalvik.system.NativeStart.main(Native Method) Thanks

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• gtk+ g++ error: invalid use of member

  - by Darragh

  #include <glib.h> #include <gtk/gtk.h> #include <iostream> using namespace std; #ifndef CONNECT4MENU_H #define CONNECT4MENU_H static gboolean deleteEvent( GtkWidget *widget, GdkEvent *event, gpointer data); static int startGame(GtkWidget *widget, GdkEvent *event, gpointer data); static int gui(); GtkWidget *window; GtkWidget *button; GtkWidget *button2; GtkWidget *button3; GtkWidget *button4; GtkWidget *button5; GtkWidget *button6; GtkWidget *box1; GtkWidget *box2; GtkWidget *box3; GtkWidget *box4; GtkWidget *box5; GtkWidget *box6; GSList *group; GSList *group2; int gamet = 0; static int gui() { window = gtk_window_new(GTK_WINDOW_TOPLEVEL); g_signal_connect(G_OBJECT(window), "delete_event", G_CALLBACK(deleteEvent), NULL); box3 = gtk_vbox_new(FALSE, 0); gtk_container_add(GTK_CONTAINER(window), box3); gtk_widget_show(box3); box1 = gtk_hbox_new(FALSE, 0); gtk_container_add(GTK_CONTAINER(box3), box1); gtk_widget_show(box1); button = gtk_radio_button_new_with_label(NULL, "1 Player"); gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0); gtk_widget_show(button); group = gtk_radio_button_get_group(GTK_RADIO_BUTTON(button)); button2 = gtk_radio_button_new_with_label(group, "2 Player"); gtk_box_pack_start(GTK_BOX(box1), button2, TRUE, TRUE, 0); gtk_widget_show(button2); box4 = gtk_vbox_new(FALSE, 0); gtk_container_add(GTK_CONTAINER(box3), box4); gtk_widget_show(box4); box2 = gtk_hbox_new(FALSE, 0); gtk_container_add(GTK_CONTAINER(box4), box2); gtk_widget_show(box2); button3 = gtk_radio_button_new_with_label(NULL, "Easy"); gtk_box_pack_start(GTK_BOX(box2), button3, TRUE, TRUE, 0); gtk_widget_show(button3); group2 = gtk_radio_button_get_group(GTK_RADIO_BUTTON(button3)); button4 = gtk_radio_button_new_with_label(group2, "Medium"); gtk_box_pack_start(GTK_BOX(box2), button4, TRUE, TRUE, 0); gtk_widget_show(button4); group2 = gtk_radio_button_get_group(GTK_RADIO_BUTTON(button4)); button5 = gtk_radio_button_new_with_label(group2, "Expert"); gtk_box_pack_start(GTK_BOX(box2), button5, TRUE, TRUE, 0); gtk_widget_show(button5); box5 = gtk_vbox_new(FALSE, 0); gtk_container_add(GTK_CONTAINER(box4), box5); gtk_widget_show(box5); button6 = gtk_button_new_with_label ("Start Game"); g_signal_connect (G_OBJECT (button6), "clicked", G_CALLBACK (startGame), NULL); gtk_box_pack_start(GTK_BOX (box5), button6, TRUE, TRUE, 0); gtk_widget_show(button6); gtk_widget_show(window); gtk_main(); } static gboolean deleteEvent(GtkWidget *widget, GdkEvent *event, gpointer data) { gtk_main_quit(); return FALSE; } static int startGame(GtkWidget *widget, GdkEvent *event, gpointer data) { if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(button))) { if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(button3))) { gamet = 1; gtk_main_quit(); } if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(button4))) { gamet = 2; gtk_main_quit(); } if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(button5))) { gamet = 3; gtk_main_quit(); } } if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(button2))) { gamet = 4; gtk_main_quit(); } } #endif The error I get when I try to compile this is: connect4menu2.h: In member function 'void menu::gui()': connect4menu2.h:46: error: invalid use of member (did you forget the '&' ?) connect4menu2.h:96: error: invalid use of member (did you forget the '&' ?) I cannot understand why I can't call startGame and deleteEvent from gui. Does anybody know why I am getting this error

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• Hosting the Razor Engine for Templating in Non-Web Applications

  - by Rick Strahl

  Microsoft’s new Razor HTML Rendering Engine that is currently shipping with ASP.NET MVC previews can be used outside of ASP.NET. Razor is an alternative view engine that can be used instead of the ASP.NET Page engine that currently works with ASP.NET WebForms and MVC. It provides a simpler and more readable markup syntax and is much more light weight in terms of functionality than the full blown WebForms Page engine, focusing only on features that are more along the lines of a pure view engine (or classic ASP!) with focus on expression and code rendering rather than a complex control/object model. Like the Page engine though, the parser understands .NET code syntax which can be embedded into templates, and behind the scenes the engine compiles markup and script code into an executing piece of .NET code in an assembly. Although it ships as part of the ASP.NET MVC and WebMatrix the Razor Engine itself is not directly dependent on ASP.NET or IIS or HTTP in any way. And although there are some markup and rendering features that are optimized for HTML based output generation, Razor is essentially a free standing template engine. And what’s really nice is that unlike the ASP.NET Runtime, Razor is fairly easy to host inside of your own non-Web applications to provide templating functionality. Templating in non-Web Applications? Yes please! So why might you host a template engine in your non-Web application? Template rendering is useful in many places and I have a number of applications that make heavy use of it. One of my applications – West Wind Html Help Builder - exclusively uses template based rendering to merge user supplied help text content into customizable and executable HTML markup templates that provide HTML output for CHM style HTML Help. This is an older product and it’s not actually using .NET at the moment – and this is one reason I’m looking at Razor for script hosting at the moment. For a few .NET applications though I’ve actually used the ASP.NET Runtime hosting to provide templating and mail merge style functionality and while that works reasonably well it’s a very heavy handed approach. It’s very resource intensive and has potential issues with versioning in various different versions of .NET. The generic implementation I created in the article above requires a lot of fix up to mimic an HTTP request in a non-HTTP environment and there are a lot of little things that have to happen to ensure that the ASP.NET runtime works properly most of it having nothing to do with the templating aspect but just satisfying ASP.NET’s requirements. The Razor Engine on the other hand is fairly light weight and completely decoupled from the ASP.NET runtime and the HTTP processing. Rather it’s a pure template engine whose sole purpose is to render text templates. Hosting this engine in your own applications can be accomplished with a reasonable amount of code (actually just a few lines with the tools I’m about to describe) and without having to fake HTTP requests. It’s also much lighter on resource usage and you can easily attach custom properties to your base template implementation to easily pass context from the parent application into templates all of which was rather complicated with ASP.NET runtime hosting. Installing the Razor Template Engine You can get Razor as part of the MVC 3 (RC and later) or Web Matrix. Both are available as downloadable components from the Web Platform Installer Version 3.0 (!important – V2 doesn’t show these components). If you already have that version of the WPI installed just fire it up. You can get the latest version of the Web Platform Installer from here: http://www.microsoft.com/web/gallery/install.aspx Once the platform Installer 3.0 is installed install either MVC 3 or ASP.NET Web Pages. Once installed you’ll find a System.Web.Razor assembly in C:\Program Files\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies\System.Web.Razor.dll which you can add as a reference to your project. Creating a Wrapper The basic Razor Hosting API is pretty simple and you can host Razor with a (large-ish) handful of lines of code. I’ll show the basics of it later in this article. However, if you want to customize the rendering and handle assembly and namespace includes for the markup as well as deal with text and file inputs as well as forcing Razor to run in a separate AppDomain so you can unload the code-generated assemblies and deal with assembly caching for re-used templates little more work is required to create something that is more easily reusable. For this reason I created a Razor Hosting wrapper project that combines a bunch of this functionality into an easy to use hosting class, a hosting factory that can load the engine in a separate AppDomain and a couple of hosting containers that provided folder based and string based caching for templates for an easily embeddable and reusable engine with easy to use syntax. If you just want the code and play with the samples and source go grab the latest code from the Subversion Repository at: http://www.west-wind.com:8080/svn/articles/trunk/RazorHosting/ or a snapshot from: http://www.west-wind.com/files/tools/RazorHosting.zip Getting Started Before I get into how hosting with Razor works, let’s take a look at how you can get up and running quickly with the wrapper classes provided. It only takes a few lines of code. The easiest way to use these Razor Hosting Wrappers is to use one of the two HostContainers provided. One is for hosting Razor scripts in a directory and rendering them as relative paths from these script files on disk. The other HostContainer serves razor scripts from string templates… Let’s start with a very simple template that displays some simple expressions, some code blocks and demonstrates rendering some data from contextual data that you pass to the template in the form of a ‘context’. Here’s a simple Razor template: @using System.Reflection Hello @Context.FirstName! Your entry was entered on: @Context.Entered @{ // Code block: Update the host Windows Form passed in through the context Context.WinForm.Text = "Hello World from Razor at " + DateTime.Now.ToString(); } AppDomain Id: @AppDomain.CurrentDomain.FriendlyName Assembly: @Assembly.GetExecutingAssembly().FullName Code based output: @{ // Write output with Response object from code string output = string.Empty; for (int i = 0; i < 10; i++) { output += i.ToString() + " "; } Response.Write(output); } Pretty easy to see what’s going on here. The only unusual thing in this code is the Context object which is an arbitrary object I’m passing from the host to the template by way of the template base class. I’m also displaying the current AppDomain and the executing Assembly name so you can see how compiling and running a template actually loads up new assemblies. Also note that as part of my context I’m passing a reference to the current Windows Form down to the template and changing the title from within the script. It’s a silly example, but it demonstrates two-way communication between host and template and back which can be very powerful. The easiest way to quickly render this template is to use the RazorEngine<TTemplateBase> class. The generic parameter specifies a template base class type that is used by Razor internally to generate the class it generates from a template. The default implementation provided in my RazorHosting wrapper is RazorTemplateBase. Here’s a simple one that renders from a string and outputs a string: var engine = new RazorEngine<RazorTemplateBase>(); // we can pass any object as context - here create a custom context var context = new CustomContext() { WinForm = this, FirstName = "Rick", Entered = DateTime.Now.AddDays(-10) }; string output = engine.RenderTemplate(this.txtSource.Text new string[] { "System.Windows.Forms.dll" }, context); if (output == null) this.txtResult.Text = "*** ERROR:\r\n" + engine.ErrorMessage; else this.txtResult.Text = output; Simple enough. This code renders a template from a string input and returns a result back as a string. It  creates a custom context and passes that to the template which can then access the Context’s properties. Note that anything passed as ‘context’ must be serializable (or MarshalByRefObject) – otherwise you get an exception when passing the reference over AppDomain boundaries (discussed later). Passing a context is optional, but is a key feature in being able to share data between the host application and the template. Note that we use the Context object to access FirstName, Entered and even the host Windows Form object which is used in the template to change the Window caption from within the script! In the code above all the work happens in the RenderTemplate method which provide a variety of overloads to read and write to and from strings, files and TextReaders/Writers. Here’s another example that renders from a file input using a TextReader: using (reader = new StreamReader("templates\\simple.csHtml", true)) { result = host.RenderTemplate(reader, new string[] { "System.Windows.Forms.dll" }, this.CustomContext); } RenderTemplate() is fairly high level and it handles loading of the runtime, compiling into an assembly and rendering of the template. If you want more control you can use the lower level methods to control each step of the way which is important for the HostContainers I’ll discuss later. Basically for those scenarios you want to separate out loading of the engine, compiling into an assembly and then rendering the template from the assembly. Why? So we can keep assemblies cached. In the code above a new assembly is created for each template rendered which is inefficient and uses up resources. Depending on the size of your templates and how often you fire them you can chew through memory very quickly. This slighter lower level approach is only a couple of extra steps: // we can pass any object as context - here create a custom context var context = new CustomContext() { WinForm = this, FirstName = "Rick", Entered = DateTime.Now.AddDays(-10) }; var engine = new RazorEngine<RazorTemplateBase>(); string assId = null; using (StringReader reader = new StringReader(this.txtSource.Text)) { assId = engine.ParseAndCompileTemplate(new string[] { "System.Windows.Forms.dll" }, reader); } string output = engine.RenderTemplateFromAssembly(assId, context); if (output == null) this.txtResult.Text = "*** ERROR:\r\n" + engine.ErrorMessage; else this.txtResult.Text = output; The difference here is that you can capture the assembly – or rather an Id to it – and potentially hold on to it to render again later assuming the template hasn’t changed. The HostContainers take advantage of this feature to cache the assemblies based on certain criteria like a filename and file time step or a string hash that if not change indicate that an assembly can be reused. Note that ParseAndCompileTemplate returns an assembly Id rather than the assembly itself. This is done so that that the assembly always stays in the host’s AppDomain and is not passed across AppDomain boundaries which would cause load failures. We’ll talk more about this in a minute but for now just realize that assemblies references are stored in a list and are accessible by this ID to allow locating and re-executing of the assembly based on that id. Reuse of the assembly avoids recompilation overhead and creation of yet another assembly that loads into the current AppDomain. You can play around with several different versions of the above code in the main sample form:   Using Hosting Containers for more Control and Caching The above examples simply render templates into assemblies each and every time they are executed. While this works and is even reasonably fast, it’s not terribly efficient. If you render templates more than once it would be nice if you could cache the generated assemblies for example to avoid re-compiling and creating of a new assembly each time. Additionally it would be nice to load template assemblies into a separate AppDomain optionally to be able to be able to unload assembli es and also to protect your host application from scripting attacks with malicious template code. Hosting containers provide also provide a wrapper around the RazorEngine<T> instance, a factory (which allows creation in separate AppDomains) and an easy way to start and stop the container ‘runtime’. The Razor Hosting samples provide two hosting containers: RazorFolderHostContainer and StringHostContainer. The folder host provides a simple runtime environment for a folder structure similar in the way that the ASP.NET runtime handles a virtual directory as it’s ‘application' root. Templates are loaded from disk in relative paths and the resulting assemblies are cached unless the template on disk is changed. The string host also caches templates based on string hashes – if the same string is passed a second time a cached version of the assembly is used. Here’s how HostContainers work. I’ll use the FolderHostContainer because it’s likely the most common way you’d use templates – from disk based templates that can be easily edited and maintained on disk. The first step is to create an instance of it and keep it around somewhere (in the example it’s attached as a property to the Form): RazorFolderHostContainer Host = new RazorFolderHostContainer(); public RazorFolderHostForm() { InitializeComponent(); // The base path for templates - templates are rendered with relative paths // based on this path. Host.TemplatePath = Path.Combine(Environment.CurrentDirectory, TemplateBaseFolder); // Add any assemblies you want reference in your templates Host.ReferencedAssemblies.Add("System.Windows.Forms.dll"); // Start up the host container Host.Start(); } Next anytime you want to render a template you can use simple code like this: private void RenderTemplate(string fileName) { // Pass the template path via the Context var relativePath = Utilities.GetRelativePath(fileName, Host.TemplatePath); if (!Host.RenderTemplate(relativePath, this.Context, Host.RenderingOutputFile)) { MessageBox.Show("Error: " + Host.ErrorMessage); return; } this.webBrowser1.Navigate("file://" + Host.RenderingOutputFile); } You can also render the output to a string instead of to a file: string result = Host.RenderTemplateToString(relativePath,context); Finally if you want to release the engine and shut down the hosting AppDomain you can simply do: Host.Stop(); Stopping the AppDomain and restarting it (ie. calling Stop(); followed by Start()) is also a nice way to release all resources in the AppDomain. The FolderBased domain also supports partial Rendering based on root path based relative paths with the same caching characteristics as the main templates. From within a template you can call out to a partial like this: @RenderPartial(@"partials\PartialRendering.cshtml", Context) where partials\PartialRendering.cshtml is a relative to the template root folder. The folder host example lets you load up templates from disk and display the result in a Web Browser control which demonstrates using Razor HTML output from templates that contain HTML syntax which happens to me my target scenario for Html Help Builder.   The Razor Engine Wrapper Project The project I created to wrap Razor hosting has a fair bit of code and a number of classes associated with it. Most of the components are internally used and as you can see using the final RazorEngine<T> and HostContainer classes is pretty easy. The classes are extensible and I suspect developers will want to build more customized host containers for their applications. Host containers are the key to wrapping up all functionality – Engine, BaseTemplate, AppDomain Hosting, Caching etc in a logical piece that is ready to be plugged into an application. When looking at the code there are a couple of core features provided: Core Razor Engine Hosting This is the core Razor hosting which provides the basics of loading a template, compiling it into an assembly and executing it. This is fairly straightforward, but without a host container that can cache assemblies based on some criteria templates are recompiled and re-created each time which is inefficient (although pretty fast). The base engine wrapper implementation also supports hosting the Razor runtime in a separate AppDomain for security and the ability to unload it on demand. Host Containers The engine hosting itself doesn’t provide any sort of ‘runtime’ service like picking up files from disk, caching assemblies and so forth. So my implementation provides two HostContainers: RazorFolderHostContainer and RazorStringHostContainer. The FolderHost works off a base directory and loads templates based on relative paths (sort of like the ASP.NET runtime does off a virtual). The HostContainers also deal with caching of template assemblies – for the folder host the file date is tracked and checked for updates and unless the template is changed a cached assembly is reused. The StringHostContainer similiarily checks string hashes to figure out whether a particular string template was previously compiled and executed. The HostContainers also act as a simple startup environment and a single reference to easily store and reuse in an application. TemplateBase Classes The template base classes are the base classes that from which the Razor engine generates .NET code. A template is parsed into a class with an Execute() method and the class is based on this template type you can specify. RazorEngine<TBaseTemplate> can receive this type and the HostContainers default to specific templates in their base implementations. Template classes are customizable to allow you to create templates that provide application specific features and interaction from the template to your host application. How does the RazorEngine wrapper work? You can browse the source code in the links above or in the repository or download the source, but I’ll highlight some key features here. Here’s part of the RazorEngine implementation that can be used to host the runtime and that demonstrates the key code required to host the Razor runtime. The RazorEngine class is implemented as a generic class to reflect the Template base class type: public class RazorEngine<TBaseTemplateType> : MarshalByRefObject where TBaseTemplateType : RazorTemplateBase The generic type is used to internally provide easier access to the template type and assignments on it as part of the template processing. The class also inherits MarshalByRefObject to allow execution over AppDomain boundaries – something that all the classes discussed here need to do since there is much interaction between the host and the template. The first two key methods deal with creating a template assembly: /// <summary> /// Creates an instance of the RazorHost with various options applied. /// Applies basic namespace imports and the name of the class to generate /// </summary> /// <param name="generatedNamespace"></param> /// <param name="generatedClass"></param> /// <returns></returns> protected RazorTemplateEngine CreateHost(string generatedNamespace, string generatedClass) { Type baseClassType = typeof(TBaseTemplateType); RazorEngineHost host = new RazorEngineHost(new CSharpRazorCodeLanguage()); host.DefaultBaseClass = baseClassType.FullName; host.DefaultClassName = generatedClass; host.DefaultNamespace = generatedNamespace; host.NamespaceImports.Add("System"); host.NamespaceImports.Add("System.Text"); host.NamespaceImports.Add("System.Collections.Generic"); host.NamespaceImports.Add("System.Linq"); host.NamespaceImports.Add("System.IO"); return new RazorTemplateEngine(host); } /// <summary> /// Parses and compiles a markup template into an assembly and returns /// an assembly name. The name is an ID that can be passed to /// ExecuteTemplateByAssembly which picks up a cached instance of the /// loaded assembly. /// /// </summary> /// <param name="namespaceOfGeneratedClass">The namespace of the class to generate from the template</param> /// <param name="generatedClassName">The name of the class to generate from the template</param> /// <param name="ReferencedAssemblies">Any referenced assemblies by dll name only. Assemblies must be in execution path of host or in GAC.</param> /// <param name="templateSourceReader">Textreader that loads the template</param> /// <remarks> /// The actual assembly isn't returned here to allow for cross-AppDomain /// operation. If the assembly was returned it would fail for cross-AppDomain /// calls. /// </remarks> /// <returns>An assembly Id. The Assembly is cached in memory and can be used with RenderFromAssembly.</returns> public string ParseAndCompileTemplate( string namespaceOfGeneratedClass, string generatedClassName, string[] ReferencedAssemblies, TextReader templateSourceReader) { RazorTemplateEngine engine = CreateHost(namespaceOfGeneratedClass, generatedClassName); // Generate the template class as CodeDom GeneratorResults razorResults = engine.GenerateCode(templateSourceReader); // Create code from the codeDom and compile CSharpCodeProvider codeProvider = new CSharpCodeProvider(); CodeGeneratorOptions options = new CodeGeneratorOptions(); // Capture Code Generated as a string for error info // and debugging LastGeneratedCode = null; using (StringWriter writer = new StringWriter()) { codeProvider.GenerateCodeFromCompileUnit(razorResults.GeneratedCode, writer, options); LastGeneratedCode = writer.ToString(); } CompilerParameters compilerParameters = new CompilerParameters(ReferencedAssemblies); // Standard Assembly References compilerParameters.ReferencedAssemblies.Add("System.dll"); compilerParameters.ReferencedAssemblies.Add("System.Core.dll"); compilerParameters.ReferencedAssemblies.Add("Microsoft.CSharp.dll"); // dynamic support! // Also add the current assembly so RazorTemplateBase is available compilerParameters.ReferencedAssemblies.Add(Assembly.GetExecutingAssembly().CodeBase.Substring(8)); compilerParameters.GenerateInMemory = Configuration.CompileToMemory; if (!Configuration.CompileToMemory) compilerParameters.OutputAssembly = Path.Combine(Configuration.TempAssemblyPath, "_" + Guid.NewGuid().ToString("n") + ".dll"); CompilerResults compilerResults = codeProvider.CompileAssemblyFromDom(compilerParameters, razorResults.GeneratedCode); if (compilerResults.Errors.Count > 0) { var compileErrors = new StringBuilder(); foreach (System.CodeDom.Compiler.CompilerError compileError in compilerResults.Errors) compileErrors.Append(String.Format(Resources.LineX0TColX1TErrorX2RN, compileError.Line, compileError.Column, compileError.ErrorText)); this.SetError(compileErrors.ToString() + "\r\n" + LastGeneratedCode); return null; } AssemblyCache.Add(compilerResults.CompiledAssembly.FullName, compilerResults.CompiledAssembly); return compilerResults.CompiledAssembly.FullName; } Think of the internal CreateHost() method as setting up the assembly generated from each template. Each template compiles into a separate assembly. It sets up namespaces, and assembly references, the base class used and the name and namespace for the generated class. ParseAndCompileTemplate() then calls the CreateHost() method to receive the template engine generator which effectively generates a CodeDom from the template – the template is turned into .NET code. The code generated from our earlier example looks something like this: //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:4.0.30319.1 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace RazorTest { using System; using System.Text; using System.Collections.Generic; using System.Linq; using System.IO; using System.Reflection; public class RazorTemplate : RazorHosting.RazorTemplateBase { #line hidden public RazorTemplate() { } public override void Execute() { WriteLiteral("Hello "); Write(Context.FirstName); WriteLiteral("! Your entry was entered on: "); Write(Context.Entered); WriteLiteral("\r\n\r\n"); // Code block: Update the host Windows Form passed in through the context Context.WinForm.Text = "Hello World from Razor at " + DateTime.Now.ToString(); WriteLiteral("\r\nAppDomain Id:\r\n "); Write(AppDomain.CurrentDomain.FriendlyName); WriteLiteral("\r\n \r\nAssembly:\r\n "); Write(Assembly.GetExecutingAssembly().FullName); WriteLiteral("\r\n\r\nCode based output: \r\n"); // Write output with Response object from code string output = string.Empty; for (int i = 0; i < 10; i++) { output += i.ToString() + " "; } } } } Basically the template’s body is turned into code in an Execute method that is called. Internally the template’s Write method is fired to actually generate the output. Note that the class inherits from RazorTemplateBase which is the generic parameter I used to specify the base class when creating an instance in my RazorEngine host: var engine = new RazorEngine<RazorTemplateBase>(); This template class must be provided and it must implement an Execute() and Write() method. Beyond that you can create any class you chose and attach your own properties. My RazorTemplateBase class implementation is very simple: public class RazorTemplateBase : MarshalByRefObject, IDisposable { /// <summary> /// You can pass in a generic context object /// to use in your template code /// </summary> public dynamic Context { get; set; } /// <summary> /// Class that generates output. Currently ultra simple /// with only Response.Write() implementation. /// </summary> public RazorResponse Response { get; set; } public object HostContainer {get; set; } public object Engine { get; set; } public RazorTemplateBase() { Response = new RazorResponse(); } public virtual void Write(object value) { Response.Write(value); } public virtual void WriteLiteral(object value) { Response.Write(value); } /// <summary> /// Razor Parser implements this method /// </summary> public virtual void Execute() {} public virtual void Dispose() { if (Response != null) { Response.Dispose(); Response = null; } } } Razor fills in the Execute method when it generates its subclass and uses the Write() method to output content. As you can see I use a RazorResponse() class here to generate output. This isn’t necessary really, as you could use a StringBuilder or StringWriter() directly, but I prefer using Response object so I can extend the Response behavior as needed. The RazorResponse class is also very simple and merely acts as a wrapper around a TextWriter: public class RazorResponse : IDisposable { /// <summary> /// Internal text writer - default to StringWriter() /// </summary> public TextWriter Writer = new StringWriter(); public virtual void Write(object value) { Writer.Write(value); } public virtual void WriteLine(object value) { Write(value); Write("\r\n"); } public virtual void WriteFormat(string format, params object[] args) { Write(string.Format(format, args)); } public override string ToString() { return Writer.ToString(); } public virtual void Dispose() { Writer.Close(); } public virtual void SetTextWriter(TextWriter writer) { // Close original writer if (Writer != null) Writer.Close(); Writer = writer; } } The Rendering Methods of RazorEngine At this point I’ve talked about the assembly generation logic and the template implementation itself. What’s left is that once you’ve generated the assembly is to execute it. The code to do this is handled in the various RenderXXX methods of the RazorEngine class. Let’s look at the lowest level one of these which is RenderTemplateFromAssembly() and a couple of internal support methods that handle instantiating and invoking of the generated template method: public string RenderTemplateFromAssembly( string assemblyId, string generatedNamespace, string generatedClass, object context, TextWriter outputWriter) { this.SetError(); Assembly generatedAssembly = AssemblyCache[assemblyId]; if (generatedAssembly == null) { this.SetError(Resources.PreviouslyCompiledAssemblyNotFound); return null; } string className = generatedNamespace + "." + generatedClass; Type type; try { type = generatedAssembly.GetType(className); } catch (Exception ex) { this.SetError(Resources.UnableToCreateType + className + ": " + ex.Message); return null; } // Start with empty non-error response (if we use a writer) string result = string.Empty; using(TBaseTemplateType instance = InstantiateTemplateClass(type)) { if (instance == null) return null; if (outputWriter != null) instance.Response.SetTextWriter(outputWriter); if (!InvokeTemplateInstance(instance, context)) return null; // Capture string output if implemented and return // otherwise null is returned if (outputWriter == null) result = instance.Response.ToString(); } return result; } protected virtual TBaseTemplateType InstantiateTemplateClass(Type type) { TBaseTemplateType instance = Activator.CreateInstance(type) as TBaseTemplateType; if (instance == null) { SetError(Resources.CouldnTActivateTypeInstance + type.FullName); return null; } instance.Engine = this; // If a HostContainer was set pass that to the template too instance.HostContainer = this.HostContainer; return instance; } /// <summary> /// Internally executes an instance of the template, /// captures errors on execution and returns true or false /// </summary> /// <param name="instance">An instance of the generated template</param> /// <returns>true or false - check ErrorMessage for errors</returns> protected virtual bool InvokeTemplateInstance(TBaseTemplateType instance, object context) { try { instance.Context = context; instance.Execute(); } catch (Exception ex) { this.SetError(Resources.TemplateExecutionError + ex.Message); return false; } finally { // Must make sure Response is closed instance.Response.Dispose(); } return true; } The RenderTemplateFromAssembly method basically requires the namespace and class to instantate and creates an instance of the class using InstantiateTemplateClass(). It then invokes the method with InvokeTemplateInstance(). These two methods are broken out because they are re-used by various other rendering methods and also to allow subclassing and providing additional configuration tasks to set properties and pass values to templates at execution time. In the default mode instantiation sets the Engine and HostContainer (discussed later) so the template can call back into the template engine, and the context is set when the template method is invoked. The various RenderXXX methods use similar code although they create the assemblies first. If you’re after potentially cashing assemblies the method is the one to call and that’s exactly what the two HostContainer classes do. More on that in a minute, but before we get into HostContainers let’s talk about AppDomain hosting and the like. Running Templates in their own AppDomain With the RazorEngine class above, when a template is parsed into an assembly and executed the assembly is created (in memory or on disk – you can configure that) and cached in the current AppDomain. In .NET once an assembly has been loaded it can never be unloaded so if you’re loading lots of templates and at some time you want to release them there’s no way to do so. If however you load the assemblies in a separate AppDomain that new AppDomain can be unloaded and the assemblies loaded in it with it. In order to host the templates in a separate AppDomain the easiest thing to do is to run the entire RazorEngine in a separate AppDomain. Then all interaction occurs in the other AppDomain and no further changes have to be made. To facilitate this there is a RazorEngineFactory which has methods that can instantiate the RazorHost in a separate AppDomain as well as in the local AppDomain. The host creates the remote instance and then hangs on to it to keep it alive as well as providing methods to shut down the AppDomain and reload the engine. Sounds complicated but cross-AppDomain invocation is actually fairly easy to implement. Here’s some of the relevant code from the RazorEngineFactory class. Like the RazorEngine this class is generic and requires a template base type in the generic class name: public class RazorEngineFactory<TBaseTemplateType> where TBaseTemplateType : RazorTemplateBase Here are the key methods of interest: /// <summary> /// Creates an instance of the RazorHost in a new AppDomain. This /// version creates a static singleton that that is cached and you /// can call UnloadRazorHostInAppDomain to unload it. /// </summary> /// <returns></returns> public static RazorEngine<TBaseTemplateType> CreateRazorHostInAppDomain() { if (Current == null) Current = new RazorEngineFactory<TBaseTemplateType>(); return Current.GetRazorHostInAppDomain(); } public static void UnloadRazorHostInAppDomain() { if (Current != null) Current.UnloadHost(); Current = null; } /// <summary> /// Instance method that creates a RazorHost in a new AppDomain. /// This method requires that you keep the Factory around in /// order to keep the AppDomain alive and be able to unload it. /// </summary> /// <returns></returns> public RazorEngine<TBaseTemplateType> GetRazorHostInAppDomain() { LocalAppDomain = CreateAppDomain(null); if (LocalAppDomain == null) return null; /// Create the instance inside of the new AppDomain /// Note: remote domain uses local EXE's AppBasePath!!! RazorEngine<TBaseTemplateType> host = null; try { Assembly ass = Assembly.GetExecutingAssembly(); string AssemblyPath = ass.Location; host = (RazorEngine<TBaseTemplateType>) LocalAppDomain.CreateInstanceFrom(AssemblyPath, typeof(RazorEngine<TBaseTemplateType>).FullName).Unwrap(); } catch (Exception ex) { ErrorMessage = ex.Message; return null; } return host; } /// <summary> /// Internally creates a new AppDomain in which Razor templates can /// be run. /// </summary> /// <param name="appDomainName"></param> /// <returns></returns> private AppDomain CreateAppDomain(string appDomainName) { if (appDomainName == null) appDomainName = "RazorHost_" + Guid.NewGuid().ToString("n"); AppDomainSetup setup = new AppDomainSetup(); // *** Point at current directory setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory; AppDomain localDomain = AppDomain.CreateDomain(appDomainName, null, setup); return localDomain; } /// <summary> /// Allow unloading of the created AppDomain to release resources /// All internal resources in the AppDomain are released including /// in memory compiled Razor assemblies. /// </summary> public void UnloadHost() { if (this.LocalAppDomain != null) { AppDomain.Unload(this.LocalAppDomain); this.LocalAppDomain = null; } } The static CreateRazorHostInAppDomain() is the key method that startup code usually calls. It uses a Current singleton instance to an instance of itself that is created cross AppDomain and is kept alive because it’s static. GetRazorHostInAppDomain actually creates a cross-AppDomain instance which first creates a new AppDomain and then loads the RazorEngine into it. The remote Proxy instance is returned as a result to the method and can be used the same as a local instance. The code to run with a remote AppDomain is simple: private RazorEngine<RazorTemplateBase> CreateHost() { if (this.Host != null) return this.Host; // Use Static Methods - no error message if host doesn't load this.Host = RazorEngineFactory<RazorTemplateBase>.CreateRazorHostInAppDomain(); if (this.Host == null) { MessageBox.Show("Unable to load Razor Template Host", "Razor Hosting", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); } return this.Host; } This code relies on a local reference of the Host which is kept around for the duration of the app (in this case a form reference). To use this you’d simply do: this.Host = CreateHost(); if (host == null) return; string result = host.RenderTemplate( this.txtSource.Text, new string[] { "System.Windows.Forms.dll", "Westwind.Utilities.dll" }, this.CustomContext); if (result == null) { MessageBox.Show(host.ErrorMessage, "Template Execution Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); return; } this.txtResult.Text = result; Now all templates run in a remote AppDomain and can be unloaded with simple code like this: RazorEngineFactory<RazorTemplateBase>.UnloadRazorHostInAppDomain(); this.Host = null; One Step further – Providing a caching ‘Runtime’ Once we can load templates in a remote AppDomain we can add some additional functionality like assembly caching based on application specific features. One of my typical scenarios is to render templates out of a scripts folder. So all templates live in a folder and they change infrequently. So a Folder based host that can compile these templates once and then only recompile them if something changes would be ideal. Enter host containers which are basically wrappers around the RazorEngine<t> and RazorEngineFactory<t>. They provide additional logic for things like file caching based on changes on disk or string hashes for string based template inputs. The folder host also provides for partial rendering logic through a custom template base implementation. There’s a base implementation in RazorBaseHostContainer, which provides the basics for hosting a RazorEngine, which includes the ability to start and stop the engine, cache assemblies and add references: public abstract class RazorBaseHostContainer<TBaseTemplateType> : MarshalByRefObject where TBaseTemplateType : RazorTemplateBase, new() { public RazorBaseHostContainer() { UseAppDomain = true; GeneratedNamespace = "__RazorHost"; } /// <summary> /// Determines whether the Container hosts Razor /// in a separate AppDomain. Seperate AppDomain /// hosting allows unloading and releasing of /// resources. /// </summary> public bool UseAppDomain { get; set; } /// <summary> /// Base folder location where the AppDomain /// is hosted. By default uses the same folder /// as the host application. /// /// Determines where binary dependencies are /// found for assembly references. /// </summary> public string BaseBinaryFolder { get; set; } /// <summary> /// List of referenced assemblies as string values. /// Must be in GAC or in the current folder of the host app/ /// base BinaryFolder /// </summary> public List<string> ReferencedAssemblies = new List<string>(); /// <summary> /// Name of the generated namespace for template classes /// </summary> public string GeneratedNamespace {get; set; } /// <summary> /// Any error messages /// </summary> public string ErrorMessage { get; set; } /// <summary> /// Cached instance of the Host. Required to keep the /// reference to the host alive for multiple uses. /// </summary> public RazorEngine<TBaseTemplateType> Engine; /// <summary> /// Cached instance of the Host Factory - so we can unload /// the host and its associated AppDomain. /// </summary> protected RazorEngineFactory<TBaseTemplateType> EngineFactory; /// <summary> /// Keep track of each compiled assembly /// and when it was compiled. /// /// Use a hash of the string to identify string /// changes. /// </summary> protected Dictionary<int, CompiledAssemblyItem> LoadedAssemblies = new Dictionary<int, CompiledAssemblyItem>(); /// <summary> /// Call to start the Host running. Follow by a calls to RenderTemplate to /// render individual templates. Call Stop when done. /// </summary> /// <returns>true or false - check ErrorMessage on false </returns> public virtual bool Start() { if (Engine == null) { if (UseAppDomain) Engine = RazorEngineFactory<TBaseTemplateType>.CreateRazorHostInAppDomain(); else Engine = RazorEngineFactory<TBaseTemplateType>.CreateRazorHost(); Engine.Configuration.CompileToMemory = true; Engine.HostContainer = this; if (Engine == null) { this.ErrorMessage = EngineFactory.ErrorMessage; return false; } } return true; } /// <summary> /// Stops the Host and releases the host AppDomain and cached /// assemblies. /// </summary> /// <returns>true or false</returns> public bool Stop() { this.LoadedAssemblies.Clear(); RazorEngineFactory<RazorTemplateBase>.UnloadRazorHostInAppDomain(); this.Engine = null; return true; } … } This base class provides most of the mechanics to host the runtime, but no application specific implementation for rendering. There are rendering functions but they just call the engine directly and provide no caching – there’s no context to decide how to cache and reuse templates. The key methods are Start and Stop and their main purpose is to start a new AppDomain (optionally) and shut it down when requested. The RazorFolderHostContainer – Folder Based Runtime Hosting Let’s look at the more application specific RazorFolderHostContainer implementation which is defined like this: public class RazorFolderHostContainer : RazorBaseHostContainer<RazorTemplateFolderHost> Note that a customized RazorTemplateFolderHost class template is used for this implementation that supports partial rendering in form of a RenderPartial() method that’s available to templates. The folder host’s features are: Render templates based on a Template Base Path (a ‘virtual’ if you will) Cache compiled assemblies based on the relative path and file time stamp File changes on templates cause templates to be recompiled into new assemblies Support for partial rendering using base folder relative pathing As shown in the startup examples earlier host containers require some startup code with a HostContainer tied to a persistent property (like a Form property): // The base path for templates - templates are rendered with relative paths // based on this path. HostContainer.TemplatePath = Path.Combine(Environment.CurrentDirectory, TemplateBaseFolder); // Default output rendering disk location HostContainer.RenderingOutputFile = Path.Combine(HostContainer.TemplatePath, "__Preview.htm"); // Add any assemblies you want reference in your templates HostContainer.ReferencedAssemblies.Add("System.Windows.Forms.dll"); // Start up the host container HostContainer.Start(); Once that’s done, you can render templates with the host container: // Pass the template path for full filename seleted with OpenFile Dialog // relativepath is: subdir\file.cshtml or file.cshtml or ..\file.cshtml var relativePath = Utilities.GetRelativePath(fileName, HostContainer.TemplatePath); if (!HostContainer.RenderTemplate(relativePath, Context, HostContainer.RenderingOutputFile)) { MessageBox.Show("Error: " + HostContainer.ErrorMessage); return; } webBrowser1.Navigate("file://" + HostContainer.RenderingOutputFile); The most critical task of the RazorFolderHostContainer implementation is to retrieve a template from disk, compile and cache it and then deal with deciding whether subsequent requests need to re-compile the template or simply use a cached version. Internally the GetAssemblyFromFileAndCache() handles this task: /// <summary> /// Internally checks if a cached assembly exists and if it does uses it /// else creates and compiles one. Returns an assembly Id to be /// used with the LoadedAssembly list. /// </summary> /// <param name="relativePath"></param> /// <param name="context"></param> /// <returns></returns> protected virtual CompiledAssemblyItem GetAssemblyFromFileAndCache(string relativePath) { string fileName = Path.Combine(TemplatePath, relativePath).ToLower(); int fileNameHash = fileName.GetHashCode(); if (!File.Exists(fileName)) { this.SetError(Resources.TemplateFileDoesnTExist + fileName); return null; } CompiledAssemblyItem item = null; this.LoadedAssemblies.TryGetValue(fileNameHash, out item); string assemblyId = null; // Check for cached instance if (item != null) { var fileTime = File.GetLastWriteTimeUtc(fileName); if (fileTime <= item.CompileTimeUtc) assemblyId = item.AssemblyId; } else item = new CompiledAssemblyItem(); // No cached instance - create assembly and cache if (assemblyId == null) { string safeClassName = GetSafeClassName(fileName); StreamReader reader = null; try { reader = new StreamReader(fileName, true); } catch (Exception ex) { this.SetError(Resources.ErrorReadingTemplateFile + fileName); return null; } assemblyId = Engine.ParseAndCompileTemplate(this.ReferencedAssemblies.ToArray(), reader); // need to ensure reader is closed if (reader != null) reader.Close(); if (assemblyId == null) { this.SetError(Engine.ErrorMessage); return null; } item.AssemblyId = assemblyId; item.CompileTimeUtc = DateTime.UtcNow; item.FileName = fileName; item.SafeClassName = safeClassName; this.LoadedAssemblies[fileNameHash] = item; } return item; } This code uses a LoadedAssembly dictionary which is comprised of a structure that holds a reference to a compiled assembly, a full filename and file timestamp and an assembly id. LoadedAssemblies (defined on the base class shown earlier) is essentially a cache for compiled assemblies and they are identified by a hash id. In the case of files the hash is a GetHashCode() from the full filename of the template. The template is checked for in the cache and if not found the file stamp is checked. If that’s newer than the cache’s compilation date the template is recompiled otherwise the version in the cache is used. All the core work defers to a RazorEngine<T> instance to ParseAndCompileTemplate(). The three rendering specific methods then are rather simple implementations with just a few lines of code dealing with parameter and return value parsing: /// <summary> /// Renders a template to a TextWriter. Useful to write output into a stream or /// the Response object. Used for partial rendering. /// </summary> /// <param name="relativePath">Relative path to the file in the folder structure</param> /// <param name="context">Optional context object or null</param> /// <param name="writer">The textwriter to write output into</param> /// <returns></returns> public bool RenderTemplate(string relativePath, object context, TextWriter writer) { // Set configuration data that is to be passed to the template (any object) Engine.TemplatePerRequestConfigurationData = new RazorFolderHostTemplateConfiguration() { TemplatePath = Path.Combine(this.TemplatePath, relativePath), TemplateRelativePath = relativePath, }; CompiledAssemblyItem item = GetAssemblyFromFileAndCache(relativePath); if (item == null) { writer.Close(); return false; } try { // String result will be empty as output will be rendered into the // Response object's stream output. However a null result denotes // an error string result = Engine.RenderTemplateFromAssembly(item.AssemblyId, context, writer); if (result == null) { this.SetError(Engine.ErrorMessage); return false; } } catch (Exception ex) { this.SetError(ex.Message); return false; } finally { writer.Close(); } return true; } /// <summary> /// Render a template from a source file on disk to a specified outputfile. /// </summary> /// <param name="relativePath">Relative path off the template root folder. Format: path/filename.cshtml</param> /// <param name="context">Any object that will be available in the template as a dynamic of this.Context</param> /// <param name="outputFile">Optional - output file where output is written to. If not specified the /// RenderingOutputFile property is used instead /// </param> /// <returns>true if rendering succeeds, false on failure - check ErrorMessage</returns> public bool RenderTemplate(string relativePath, object context, string outputFile) { if (outputFile == null) outputFile = RenderingOutputFile; try { using (StreamWriter writer = new StreamWriter(outputFile, false, Engine.Configuration.OutputEncoding, Engine.Configuration.StreamBufferSize)) { return RenderTemplate(relativePath, context, writer); } } catch (Exception ex) { this.SetError(ex.Message); return false; } return true; } /// <summary> /// Renders a template to string. Useful for RenderTemplate /// </summary> /// <param name="relativePath"></param> /// <param name="context"></param> /// <returns></returns> public string RenderTemplateToString(string relativePath, object context) { string result = string.Empty; try { using (StringWriter writer = new StringWriter()) { // String result will be empty as output will be rendered into the // Response object's stream output. However a null result denotes // an error if (!RenderTemplate(relativePath, context, writer)) { this.SetError(Engine.ErrorMessage); return null; } result = writer.ToString(); } } catch (Exception ex) { this.SetError(ex.Message); return null; } return result; } The idea is that you can create custom host container implementations that do exactly what you want fairly easily. Take a look at both the RazorFolderHostContainer and RazorStringHostContainer classes for the basic concepts you can use to create custom implementations. Notice also that you can set the engine’s PerRequestConfigurationData() from the host container: // Set configuration data that is to be passed to the template (any object) Engine.TemplatePerRequestConfigurationData = new RazorFolderHostTemplateConfiguration() { TemplatePath = Path.Combine(this.TemplatePath, relativePath), TemplateRelativePath = relativePath, }; which when set to a non-null value is passed to the Template’s InitializeTemplate() method. This method receives an object parameter which you can cast as needed: public override void InitializeTemplate(object configurationData) { // Pick up configuration data and stuff into Request object RazorFolderHostTemplateConfiguration config = configurationData as RazorFolderHostTemplateConfiguration; this.Request.TemplatePath = config.TemplatePath; this.Request.TemplateRelativePath = config.TemplateRelativePath; } With this data you can then configure any custom properties or objects on your main template class. It’s an easy way to pass data from the HostContainer all the way down into the template. The type you use is of type object so you have to cast it yourself, and it must be serializable since it will likely run in a separate AppDomain. This might seem like an ugly way to pass data around – normally I’d use an event delegate to call back from the engine to the host, but since this is running over AppDomain boundaries events get really tricky and passing a template instance back up into the host over AppDomain boundaries doesn’t work due to serialization issues. So it’s easier to pass the data from the host down into the template using this rather clumsy approach of set and forward. It’s ugly, but it’s something that can be hidden in the host container implementation as I’ve done here. It’s also not something you have to do in every implementation so this is kind of an edge case, but I know I’ll need to pass a bunch of data in some of my applications and this will be the easiest way to do so. Summing Up Hosting the Razor runtime is something I got jazzed up about quite a bit because I have an immediate need for this type of templating/merging/scripting capability in an application I’m working on. I’ve also been using templating in many apps and it’s always been a pain to deal with. The Razor engine makes this whole experience a lot cleaner and more light weight and with these wrappers I can now plug .NET based templating into my code literally with a few lines of code. That’s something to cheer about… I hope some of you will find this useful as well… Resources The examples and code require that you download the Razor runtimes. Projects are for Visual Studio 2010 running on .NET 4.0 Platform Installer 3.0 (install WebMatrix or MVC 3 for Razor Runtimes) Latest Code in Subversion Repository Download Snapshot of the Code Documentation (CHM Help File) © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  .NET  

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• Metro: Creating an IndexedDbDataSource for WinJS

  - by Stephen.Walther

  The goal of this blog entry is to describe how you can create custom data sources which you can use with the controls in the WinJS library. In particular, I explain how you can create an IndexedDbDataSource which you can use to store and retrieve data from an IndexedDB database. If you want to skip ahead, and ignore all of the fascinating content in-between, I’ve included the complete code for the IndexedDbDataSource at the very bottom of this blog entry. What is IndexedDB? IndexedDB is a database in the browser. You can use the IndexedDB API with all modern browsers including Firefox, Chrome, and Internet Explorer 10. And, of course, you can use IndexedDB with Metro style apps written with JavaScript. If you need to persist data in a Metro style app written with JavaScript then IndexedDB is a good option. Each Metro app can only interact with its own IndexedDB databases. And, IndexedDB provides you with transactions, indices, and cursors – the elements of any modern database. An IndexedDB database might be different than the type of database that you normally use. An IndexedDB database is an object-oriented database and not a relational database. Instead of storing data in tables, you store data in object stores. You store JavaScript objects in an IndexedDB object store. You create new IndexedDB object stores by handling the upgradeneeded event when you attempt to open a connection to an IndexedDB database. For example, here’s how you would both open a connection to an existing database named TasksDB and create the TasksDB database when it does not already exist: var reqOpen = window.indexedDB.open(“TasksDB”, 2); reqOpen.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); }; reqOpen.onsuccess = function () { var db = reqOpen.result; // Do something with db }; When you call window.indexedDB.open(), and the database does not already exist, then the upgradeneeded event is raised. In the code above, the upgradeneeded handler creates a new object store named tasks. The new object store has an auto-increment column named id which acts as the primary key column. If the database already exists with the right version, and you call window.indexedDB.open(), then the success event is raised. At that point, you have an open connection to the existing database and you can start doing something with the database. You use asynchronous methods to interact with an IndexedDB database. For example, the following code illustrates how you would add a new object to the tasks object store: var transaction = db.transaction(“tasks”, “readwrite”); var reqAdd = transaction.objectStore(“tasks”).add({ name: “Feed the dog” }); reqAdd.onsuccess = function() { // Tasks added successfully }; The code above creates a new database transaction, adds a new task to the tasks object store, and handles the success event. If the new task gets added successfully then the success event is raised. Creating a WinJS IndexedDbDataSource The most powerful control in the WinJS library is the ListView control. This is the control that you use to display a collection of items. If you want to display data with a ListView control, you need to bind the control to a data source. The WinJS library includes two objects which you can use as a data source: the List object and the StorageDataSource object. The List object enables you to represent a JavaScript array as a data source and the StorageDataSource enables you to represent the file system as a data source. If you want to bind an IndexedDB database to a ListView then you have a choice. You can either dump the items from the IndexedDB database into a List object or you can create a custom data source. I explored the first approach in a previous blog entry. In this blog entry, I explain how you can create a custom IndexedDB data source. Implementing the IListDataSource Interface You create a custom data source by implementing the IListDataSource interface. This interface contains the contract for the methods which the ListView needs to interact with a data source. The easiest way to implement the IListDataSource interface is to derive a new object from the base VirtualizedDataSource object. The VirtualizedDataSource object requires a data adapter which implements the IListDataAdapter interface. Yes, because of the number of objects involved, this is a little confusing. Your code ends up looking something like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); The code above is used to create a new class named IndexedDbDataSource which derives from the base VirtualizedDataSource class. In the constructor for the new class, the base class _baseDataSourceConstructor() method is called. A data adapter is passed to the _baseDataSourceConstructor() method. The code above creates a new method exposed by the IndexedDbDataSource named nuke(). The nuke() method deletes all of the objects from an object store. The code above also overrides a method named remove(). Our derived remove() method accepts any type of key and removes the matching item from the object store. Almost all of the work of creating a custom data source goes into building the data adapter class. The data adapter class implements the IListDataAdapter interface which contains the following methods: · change() · getCount() · insertAfter() · insertAtEnd() · insertAtStart() · insertBefore() · itemsFromDescription() · itemsFromEnd() · itemsFromIndex() · itemsFromKey() · itemsFromStart() · itemSignature() · moveAfter() · moveBefore() · moveToEnd() · moveToStart() · remove() · setNotificationHandler() · compareByIdentity Fortunately, you are not required to implement all of these methods. You only need to implement the methods that you actually need. In the case of the IndexedDbDataSource, I implemented the getCount(), itemsFromIndex(), insertAtEnd(), and remove() methods. If you are creating a read-only data source then you really only need to implement the getCount() and itemsFromIndex() methods. Implementing the getCount() Method The getCount() method returns the total number of items from the data source. So, if you are storing 10,000 items in an object store then this method would return the value 10,000. Here’s how I implemented the getCount() method: getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); } The first thing that you should notice is that the getCount() method returns a WinJS promise. This is a requirement. The getCount() method is asynchronous which is a good thing because all of the IndexedDB methods (at least the methods implemented in current browsers) are also asynchronous. The code above retrieves an object store and then uses the IndexedDB count() method to get a count of the items in the object store. The value is returned from the promise by calling complete(). Implementing the itemsFromIndex method When a ListView displays its items, it calls the itemsFromIndex() method. By default, it calls this method multiple times to get different ranges of items. Three parameters are passed to the itemsFromIndex() method: the requestIndex, countBefore, and countAfter parameters. The requestIndex indicates the index of the item from the database to show. The countBefore and countAfter parameters represent hints. These are integer values which represent the number of items before and after the requestIndex to retrieve. Again, these are only hints and you can return as many items before and after the request index as you please. Here’s how I implemented the itemsFromIndex method: itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); } In the code above, a cursor is used to iterate through the objects in an object store. You fetch the next item in the cursor by calling either the cursor.continue() or cursor.advance() method. The continue() method moves forward by one object and the advance() method moves forward a specified number of objects. Each time you call continue() or advance(), the success event is raised again. If the cursor is null then you know that you have reached the end of the cursor and you can return the results. Some things to be careful about here. First, the return value from the itemsFromIndex() method must implement the IFetchResult interface. In particular, you must return an object which has an items, offset, and totalCount property. Second, each item in the items array must implement the IListItem interface. Each item should have a key and a data property. Implementing the insertAtEnd() Method When creating the IndexedDbDataSource, I wanted to go beyond creating a simple read-only data source and support inserting and deleting objects. If you want to support adding new items with your data source then you need to implement the insertAtEnd() method. Here’s how I implemented the insertAtEnd() method for the IndexedDbDataSource: insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); } When implementing the insertAtEnd() method, you need to be careful to return an object which implements the IItem interface. In particular, you should return an object that has a key and a data property. The key must be a string and it uniquely represents the new item added to the data source. The value of the data property represents the new item itself. Implementing the remove() Method Finally, you use the remove() method to remove an item from the data source. You call the remove() method with the key of the item which you want to remove. Implementing the remove() method in the case of the IndexedDbDataSource was a little tricky. The problem is that an IndexedDB object store uses an integer key and the VirtualizedDataSource requires a string key. For that reason, I needed to override the remove() method in the derived IndexedDbDataSource class like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); When you call remove(), you end up calling a method of the IndexedDbDataAdapter named removeInternal() . Here’s what the removeInternal() method looks like: setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); } The removeInternal() method calls the IndexedDB delete() method to delete an item from the object store. If the item is deleted successfully then the _notificationHandler.remove() method is called. Because we are not implementing the standard IListDataAdapter remove() method, we need to notify the data source (and the ListView control bound to the data source) that an item has been removed. The way that you notify the data source is by calling the _notificationHandler.remove() method. Notice that we get the _notificationHandler in the code above by implementing another method in the IListDataAdapter interface: the setNotificationHandler() method. You can raise the following types of notifications using the _notificationHandler: · beginNotifications() · changed() · endNotifications() · inserted() · invalidateAll() · moved() · removed() · reload() These methods are all part of the IListDataNotificationHandler interface in the WinJS library. Implementing the nuke() Method I wanted to implement a method which would remove all of the items from an object store. Therefore, I created a method named nuke() which calls the IndexedDB clear() method: nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); } Notice that the nuke() method calls the _notificationHandler.reload() method to notify the ListView to reload all of the items from its data source. Because we are implementing a custom method here, we need to use the _notificationHandler to send an update. Using the IndexedDbDataSource To illustrate how you can use the IndexedDbDataSource, I created a simple task list app. You can add new tasks, delete existing tasks, and nuke all of the tasks. You delete an item by selecting an item (swipe or right-click) and clicking the Delete button. Here’s the HTML page which contains the ListView, the form for adding new tasks, and the buttons for deleting and nuking tasks: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>DataSources</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.1.0.RC/css/ui-dark.css" rel="stylesheet" /> <script src="//Microsoft.WinJS.1.0.RC/js/base.js"></script> <script src="//Microsoft.WinJS.1.0.RC/js/ui.js"></script> <!-- DataSources references --> <link href="indexedDb.css" rel="stylesheet" /> <script type="text/javascript" src="indexedDbDataSource.js"></script> <script src="indexedDb.js"></script> </head> <body> <div id="tmplTask" data-win-control="WinJS.Binding.Template"> <div class="taskItem"> Id: <span data-win-bind="innerText:id"></span> <br /><br /> Name: <span data-win-bind="innerText:name"></span> </div> </div> <div id="lvTasks" data-win-control="WinJS.UI.ListView" data-win-options="{ itemTemplate: select('#tmplTask'), selectionMode: 'single' }"></div> <form id="frmAdd"> <fieldset> <legend>Add Task</legend> <label>New Task</label> <input id="inputTaskName" required /> <button>Add</button> </fieldset> </form> <button id="btnNuke">Nuke</button> <button id="btnDelete">Delete</button> </body> </html> And here is the JavaScript code for the TaskList app: /// <reference path="//Microsoft.WinJS.1.0.RC/js/base.js" /> /// <reference path="//Microsoft.WinJS.1.0.RC/js/ui.js" /> function init() { WinJS.UI.processAll().done(function () { var lvTasks = document.getElementById("lvTasks").winControl; // Bind the ListView to its data source var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; // Wire-up Add, Delete, Nuke buttons document.getElementById("frmAdd").addEventListener("submit", function (evt) { evt.preventDefault(); tasksDataSource.beginEdits(); tasksDataSource.insertAtEnd(null, { name: document.getElementById("inputTaskName").value }).done(function (newItem) { tasksDataSource.endEdits(); document.getElementById("frmAdd").reset(); lvTasks.ensureVisible(newItem.index); }); }); document.getElementById("btnDelete").addEventListener("click", function () { if (lvTasks.selection.count() == 1) { lvTasks.selection.getItems().done(function (items) { tasksDataSource.remove(items[0].data.id); }); } }); document.getElementById("btnNuke").addEventListener("click", function () { tasksDataSource.nuke(); }); // This method is called to initialize the IndexedDb database function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } }); } document.addEventListener("DOMContentLoaded", init); The IndexedDbDataSource is created and bound to the ListView control with the following two lines of code: var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; The IndexedDbDataSource is created with four parameters: the name of the database to create, the version of the database to create, the name of the object store to create, and a function which contains code to initialize the new database. The upgrade function creates a new object store named tasks with an auto-increment property named id: function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } The Complete Code for the IndexedDbDataSource Here’s the complete code for the IndexedDbDataSource: (function () { /************************************************ * The IndexedDBDataAdapter enables you to work * with a HTML5 IndexedDB database. *************************************************/ var IndexedDbDataAdapter = WinJS.Class.define( function (dbName, dbVersion, objectStoreName, upgrade, error) { this._dbName = dbName; // database name this._dbVersion = dbVersion; // database version this._objectStoreName = objectStoreName; // object store name this._upgrade = upgrade; // database upgrade script this._error = error || function (evt) { console.log(evt.message); }; }, { /******************************************* * IListDataAdapter Interface Methods ********************************************/ getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); }, itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); }, insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); }, setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, /***************************************** * IndexedDbDataSource Method ******************************************/ removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); }, nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); }, /******************************************* * Private Methods ********************************************/ _ensureDbOpen: function () { var that = this; // Try to get cached Db if (that._cachedDb) { return WinJS.Promise.wrap(that._cachedDb); } // Otherwise, open the database return new WinJS.Promise(function (complete, error, progress) { var reqOpen = window.indexedDB.open(that._dbName, that._dbVersion); reqOpen.onerror = function (evt) { error(); }; reqOpen.onupgradeneeded = function (evt) { that._upgrade(evt); that._notificationHandler.invalidateAll(); }; reqOpen.onsuccess = function () { that._cachedDb = reqOpen.result; complete(that._cachedDb); }; }); }, _getObjectStore: function (type) { type = type || "readonly"; var that = this; return new WinJS.Promise(function (complete, error) { that._ensureDbOpen().then(function (db) { var transaction = db.transaction(that._objectStoreName, type); complete(transaction.objectStore(that._objectStoreName)); }); }); }, _get: function (key) { return new WinJS.Promise(function (complete, error) { that._getObjectStore().done(function (store) { var reqGet = store.get(key); reqGet.onerror = that._error; reqGet.onsuccess = function (item) { complete(item); }; }); }); } } ); var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); WinJS.Namespace.define("DataSources", { IndexedDbDataSource: IndexedDbDataSource }); })(); Summary In this blog post, I provided an overview of how you can create a new data source which you can use with the WinJS library. I described how you can create an IndexedDbDataSource which you can use to bind a ListView control to an IndexedDB database. While describing how you can create a custom data source, I explained how you can implement the IListDataAdapter interface. You also learned how to raise notifications — such as a removed or invalidateAll notification — by taking advantage of the methods of the IListDataNotificationHandler interface.

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• Double vs Single Quotes in Chrome

  - by Rodrigo

  So when you want to embed google docs on a site you are given this chunk of code: <iframe width='500' height='300' frameborder='0' src='https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AiV6Vq32hBZIdHZRN3EwWERLZHVUT25ST01LTGxubWc&output=html&widget=true'></iframe> This works fine on my site. If you edit the page, we run the new content through some filters to escape out stuff and make sure it is valid html. After the process, the link above gets converted to this: <iframe frameborder="0" height="300" src="https://docs.google.com/spreadsheet/pub?hl=en_US&amp;hl=en_US&amp;key=0AiV6Vq32hBZIdHZRN3EwWERLZHVUT25ST01LTGxubWc&amp;output=html&amp;widget=true" width="500"></iframe> This will work on every browser except for chrome. Chrome thinks I am running JS in the src. I narrowed it down to a combination of double quotes and escaped '&' symbols. If i revert one of those back to the original state, the iframe works. I work in ruby where ' and " have different behaviors. Is Chrome doing the same thing? Is there a way to turn that off?

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• .html extension or no for SEO purposes

  - by Scott Schluer

  I know this question has been asked before on Stack Overflow, but what I have not been able to find in the posts I've read are concrete references as to WHY one is better than the other (something I can take to my boss). So I'm working on an MVC 3 application that is basically a rewrite of the existing production application (web forms) using MVC. The current site uses a URL rewriter to rewrite "friendly" urls with HTML extensions to their ASPX counterpart. i.e. http://www.site.com/products/18554-widget.html gets rewritten to http://www.site.com/products.aspx?id=18554 We're moving away from this with the MVC site, but the powers that be still want the HTML extension on the URLs. As a developer, that just feels wrong on an MVC site. I've written a quick and dirty HttpModule that will perform a 301 redirect from the .html URL to the same URL without the .html extension and it works fine, but I need to convince management that removing the .html extension is not going to hurt SEO. I'd prefer to have this sort of friendly URL: http://www.site.com/products/18554-widget Can anyone provide information to back up my position or am I actually trying to do something that WOULD hurt SEO, in which case can you provide references on that?

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• StreamInsight 2.1, meet LINQ

  - by Roman Schindlauer

  Someone recently called LINQ “magic” in my hearing. I leapt to LINQ’s defense immediately. Turns out some people don’t realize “magic” is can be a pejorative term. I thought LINQ needed demystification. Here’s your best demystification resource: http://blogs.msdn.com/b/mattwar/archive/2008/11/18/linq-links.aspx. I won’t repeat much of what Matt Warren says in his excellent series, but will talk about some core ideas and how they affect the 2.1 release of StreamInsight. Let’s tell the story of a LINQ query. Compile time It begins with some code: IQueryable<Product> products = ...; var query = from p in products             where p.Name == "Widget"             select p.ProductID; foreach (int id in query) {     ... When the code is compiled, the C# compiler (among other things) de-sugars the query expression (see C# spec section 7.16): ... var query = products.Where(p => p.Name == "Widget").Select(p => p.ProductID); ... Overload resolution subsequently binds the Queryable.Where<Product> and Queryable.Select<Product, int> extension methods (see C# spec sections 7.5 and 7.6.5). After overload resolution, the compiler knows something interesting about the anonymous functions (lambda syntax) in the de-sugared code: they must be converted to expression trees, i.e.,“an object structure that represents the structure of the anonymous function itself” (see C# spec section 6.5). The conversion is equivalent to the following rewrite: ... var prm1 = Expression.Parameter(typeof(Product), "p"); var prm2 = Expression.Parameter(typeof(Product), "p"); var query = Queryable.Select<Product, int>(     Queryable.Where<Product>(         products,         Expression.Lambda<Func<Product, bool>>(Expression.Property(prm1, "Name"), prm1)),         Expression.Lambda<Func<Product, int>>(Expression.Property(prm2, "ProductID"), prm2)); ... If the “products” expression had type IEnumerable<Product>, the compiler would have chosen the Enumerable.Where and Enumerable.Select extension methods instead, in which case the anonymous functions would have been converted to delegates. At this point, we’ve reduced the LINQ query to familiar code that will compile in C# 2.0. (Note that I’m using C# snippets to illustrate transformations that occur in the compiler, not to suggest a viable compiler design!) Runtime When the above program is executed, the Queryable.Where method is invoked. It takes two arguments. The first is an IQueryable<> instance that exposes an Expression property and a Provider property. The second is an expression tree. The Queryable.Where method implementation looks something like this: public static IQueryable<T> Where<T>(this IQueryable<T> source, Expression<Func<T, bool>> predicate) {     return source.Provider.CreateQuery<T>(     Expression.Call(this method, source.Expression, Expression.Quote(predicate))); } Notice that the method is really just composing a new expression tree that calls itself with arguments derived from the source and predicate arguments. Also notice that the query object returned from the method is associated with the same provider as the source query. By invoking operator methods, we’re constructing an expression tree that describes a query. Interestingly, the compiler and operator methods are colluding to construct a query expression tree. The important takeaway is that expression trees are built in one of two ways: (1) by the compiler when it sees an anonymous function that needs to be converted to an expression tree, and; (2) by a query operator method that constructs a new queryable object with an expression tree rooted in a call to the operator method (self-referential). Next we hit the foreach block. At this point, the power of LINQ queries becomes apparent. The provider is able to determine how the query expression tree is evaluated! The code that began our story was intentionally vague about the definition of the “products” collection. Maybe it is a queryable in-memory collection of products: var products = new[]     { new Product { Name = "Widget", ProductID = 1 } }.AsQueryable(); The in-memory LINQ provider works by rewriting Queryable method calls to Enumerable method calls in the query expression tree. It then compiles the expression tree and evaluates it. It should be mentioned that the provider does not blindly rewrite all Queryable calls. It only rewrites a call when its arguments have been rewritten in a way that introduces a type mismatch, e.g. the first argument to Queryable.Where<Product> being rewritten as an expression of type IEnumerable<Product> from IQueryable<Product>. The type mismatch is triggered initially by a “leaf” expression like the one associated with the AsQueryable query: when the provider recognizes one of its own leaf expressions, it replaces the expression with the original IEnumerable<> constant expression. I like to think of this rewrite process as “type irritation” because the rewritten leaf expression is like a foreign body that triggers an immune response (further rewrites) in the tree. The technique ensures that only those portions of the expression tree constructed by a particular provider are rewritten by that provider: no type irritation, no rewrite. Let’s consider the behavior of an alternative LINQ provider. If “products” is a collection created by a LINQ to SQL provider: var products = new NorthwindDataContext().Products; the provider rewrites the expression tree as a SQL query that is then evaluated by your favorite RDBMS. The predicate may ultimately be evaluated using an index! In this example, the expression associated with the Products property is the “leaf” expression. StreamInsight 2.1 For the in-memory LINQ to Objects provider, a leaf is an in-memory collection. For LINQ to SQL, a leaf is a table or view. When defining a “process” in StreamInsight 2.1, what is a leaf? To StreamInsight a leaf is logic: an adapter, a sequence, or even a query targeting an entirely different LINQ provider! How do we represent the logic? Remember that a standing query may outlive the client that provisioned it. A reference to a sequence object in the client application is therefore not terribly useful. But if we instead represent the code constructing the sequence as an expression, we can host the sequence in the server: using (var server = Server.Connect(...)) {     var app = server.Applications["my application"];     var source = app.DefineObservable(() => Observable.Range(0, 10, Scheduler.NewThread));     var query = from i in source where i % 2 == 0 select i; } Example 1: defining a source and composing a query Let’s look in more detail at what’s happening in example 1. We first connect to the remote server and retrieve an existing app. Next, we define a simple Reactive sequence using the Observable.Range method. Notice that the call to the Range method is in the body of an anonymous function. This is important because it means the source sequence definition is in the form of an expression, rather than simply an opaque reference to an IObservable<int> object. The variation in Example 2 fails. Although it looks similar, the sequence is now a reference to an in-memory observable collection: var local = Observable.Range(0, 10, Scheduler.NewThread); var source = app.DefineObservable(() => local); // can’t serialize ‘local’! Example 2: error referencing unserializable local object The Define* methods support definitions of operator tree leaves that target the StreamInsight server. These methods all have the same basic structure. The definition argument is a lambda expression taking between 0 and 16 arguments and returning a source or sink. The method returns a proxy for the source or sink that can then be used for the usual style of LINQ query composition. The “define” methods exploit the compile-time C# feature that converts anonymous functions into translatable expression trees! Query composition exploits the runtime pattern that allows expression trees to be constructed by operators taking queryable and expression (Expression<>) arguments. The practical upshot: once you’ve Defined a source, you can compose LINQ queries in the familiar way using query expressions and operator combinators. Notably, queries can be composed using pull-sequences (LINQ to Objects IQueryable<> inputs), push sequences (Reactive IQbservable<> inputs), and temporal sequences (StreamInsight IQStreamable<> inputs). You can even construct processes that span these three domains using “bridge” method overloads (ToEnumerable, ToObservable and To*Streamable). Finally, the targeted rewrite via type irritation pattern is used to ensure that StreamInsight computations can leverage other LINQ providers as well. Consider the following example (this example depends on Interactive Extensions): var source = app.DefineEnumerable((int id) =>     EnumerableEx.Using(() =>         new NorthwindDataContext(), context =>             from p in context.Products             where p.ProductID == id             select p.ProductName)); Within the definition, StreamInsight has no reason to suspect that it ‘owns’ the Queryable.Where and Queryable.Select calls, and it can therefore defer to LINQ to SQL! Let’s use this source in the context of a StreamInsight process: var sink = app.DefineObserver(() => Observer.Create<string>(Console.WriteLine)); var query = from name in source(1).ToObservable()             where name == "Widget"             select name; using (query.Bind(sink).Run("process")) {     ... } When we run the binding, the source portion which filters on product ID and projects the product name is evaluated by SQL Server. Outside of the definition, responsibility for evaluation shifts to the StreamInsight server where we create a bridge to the Reactive Framework (using ToObservable) and evaluate an additional predicate. It’s incredibly easy to define computations that span multiple domains using these new features in StreamInsight 2.1! Regards, The StreamInsight Team

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• Microeconomical simulation: coordination/planning between self-interested trading agents

  - by Milton Manfried

  In a typical perfect-information strategy game like Chess, an agent can calculate its best move by searching the state tree for the best possible move, while assuming that the opponent will also make the best possible move (i.e. Mini-max). I would like to use this approach in a "game" modeling economic activity, where the possible "moves" would be to buy or sell for a given price, and the goal, rather than a specific class of states (e.g. Checkmate), would be to maximize some function F of the agent's state (e.g. F(money, widget) = 10*money + widget). How to handle buy/sell actions that require coordination between both parties, at the very least agreement upon a price? The cheap way out would be to set the price beforehand, maybe based upon the current supply -- but the idea of this simulation is to examine how prices emerge when freely determined by "perfectly rational" agents. A great example of what I do not want is the trading algorithm in SugarScape -- paraphrasing from Growing Artificial Societies p101-102: when a pair of agents interact to trade, they each compute their internal valuations of the goods, then a bargaining process is conducted and a price is agreed to. If this price makes both agents better off, they complete the transaction The protocol itself is beautiful, but what it cannot capture (as far as I can tell) is the ability for an agent to pay more than it might otherwise for a good, because it knows that it can sell it for even more at a later date -- what appears to be called "strategic thinking" in this pape at Google Books Multi-Agent-Based Simulation III: 4th International Workshop, MABS 2003... to get realistic behavior like that, it seems one would either (1) have to build an outrageously-complex internal valuation system which could at best only cover situations that were planned for at compile-time, or otherwise (2) have some mechanism to search the state tree... which would require some way of planning future trades. Note: The chess analogy only works as far as the state-space search goes; the simulation isn't intended to be "zero sum", so a literal mini-max search wouldn't be appropriate -- and ideally, it should work with more than two agents.

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• Authenticate with Django 1.5

  - by gorjuce

  I'm currently testing django 1.5 and a custom User model, but I've some problems. I've created a User class in my account app, which looks like: class User(AbstractBaseUser): email = models.EmailField() activation_key = models.CharField(max_length=255) is_active = models.BooleanField(default=False) is_admin = models.BooleanField(default=False) USERNAME_FIELD = 'email' I can correctly register a user, who is stored in my account_user table. Now, how can I log in? I've tried with: def login(request): form = AuthenticationForm() if request.method == 'POST': form = AuthenticationForm(request.POST) email = request.POST['username'] password = request.POST['password'] user = authenticate(username=email, password=password) if user is not None: if user.is_active: login(user) else: message = 'disabled account, check validation email' return render( request, 'account-login-failed.html', {'message': message} ) return render(request, 'account-login.html', {'form': form}) I can correctly register a new User My forms.py which contains my register form class RegisterForm(forms.ModelForm): """ a form to create user""" password = forms.CharField( label="Password", widget=forms.PasswordInput() ) password_confirm = forms.CharField( label="Password Repeat", widget=forms.PasswordInput() ) class Meta: model = User exclude = ('last_login', 'activation_key') def clean_password_confirm(self): password = self.cleaned_data.get("password") password_confirm = self.cleaned_data.get("password_confirm") if password and password_confirm and password != password_confirm: raise forms.ValidationError("Password don't math") return password_confirm def clean_email(self): if User.objects.filter(email__iexact=self.cleaned_data.get("email")): raise forms.ValidationError("email already exists") return self.cleaned_data['email'] def save(self): user = super(RegisterForm, self).save(commit=False) user.password = self.cleaned_data['password'] user.activation_key = generate_sha1(user.email) user.save() return user My question is: Why does authenticate give me None? I know I'm trying to authenticate() with an email as username but is that not one of the reasons to use a custom User model?

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• How to choose between Tell don't Ask and Command Query Separation?

  - by Dakotah North

  The principle Tell Don't Ask says: you should endeavor to tell objects what you want them to do; do not ask them questions about their state, make a decision, and then tell them what to do. The problem is that, as the caller, you should not be making decisions based on the state of the called object that result in you then changing the state of the object. The logic you are implementing is probably the called object’s responsibility, not yours. For you to make decisions outside the object violates its encapsulation. A simple example of "Tell, don't Ask" is Widget w = ...; if (w.getParent() != null) { Panel parent = w.getParent(); parent.remove(w); } and the tell version is ... Widget w = ...; w.removeFromParent(); But what if I need to know the result from the removeFromParent method? My first reaction was just to change the removeFromParent to return a boolean denoting if the parent was removed or not. But then I came across Command Query Separation Pattern which says NOT to do this. It states that every method should either be a command that performs an action, or a query that returns data to the caller, but not both. In other words, asking a question should not change the answer. More formally, methods should return a value only if they are referentially transparent and hence possess no side effects. Are these two really at odds with each other and how do I choose between the two? Do I go with the Pragmatic Programmer or Bertrand Meyer on this?

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• Android ListView style

  - by xger86x

  Hi, I have a question about list views. I hope someone knows the solution, because I have been trying to solve this problem all weekend. I have a custom list view in which every row have a custom .xml (item_row.xml) with a set color background for the row item. <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="70dip" android:orientation="vertical" android:background="@drawable/list_bg"> The problem is that when I try to make a selector for the list. I want two things: When the item is focused, the typical orange rectangle should appear over it, and the same When the item is pressed. I have proved with a selector and a custom style but all I get is or the selector doesn't appear or the selector covering the item so I can't see it. If anyone could help me with finding the right code I would be very grateful. Thanks

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• Cannot complete a basic task in QT4

  - by Harun Baris Bulut

  Hi all, I cannot open a new window in QT. I new in QT so I think I am missing something. I only write the code below and settings windows just shows itself and closes. I have commented out destructor but still problem persists. SettingsWindow s; s.show(); What do I do wrong ? By the way I cannot either debug it, debuger does not stop when it reaches to the first line for example. Thanks

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• How can specific type details be filtered from Dia2Dump ?

  - by Usman

  Hello, I need to filter details of specific Type(i.e Custom Type) . DIA2Dump blindly dump everything as type. I need to give it specific custom type as string and as result need all data members(i.e data section of that class). Is there any specific function available in DIA SDK for this. say I have Custom type MyClass and it has 4 variables as data members i.e DWORD data, DWORD location, BOOL MachineType and FLOAT Price. Now I should be able to pass MyClass as in parameter and it should output as data members(listed above as data,location...) of this class. How..?? Regards Regards Usman

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• DataAnnotations Automatic Handling of int is Causing a Roadblock

  - by DM

  Summary: DataAnnotation's automatic handling of an "int?" is making me rethink using them at all. Maybe I'm missing something and an easy fix but I can't get DataAnnotations to cooperate. I have a public property with my own custom validation attribute: [MustBeNumeric(ErrorMessage = "Must be a number")] public int? Weight { get; set; } The point of the custom validation attribute is do a quick check to see if the input is numeric and display an appropriate error message. The problem is that when DataAnnotations tries to bind a string to the int? is automatically doesn't validate and displays a "The value 'asdf' is not valid for Weight." For the life of me I can't get DataAnnotations to stop handling that so I can take care of it in my custom attribute. This seems like it would be a popular scenario (to validate that the input in numeric) and I'm guessing there's an easy solution but I didn't find it anywhere.

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• FluentNhibernate IDictionary<Entity,ValueObject>

  - by Miguel Marques

  I had a mapping for a IDictionary<StocksLocation,decimal> property, this was the mapping: HasMany<StocksLocation>(mq => mq.StocksLocation) .KeyColumn("IDProduct") .AsEntityMap("IDLocation") .Element("Quantity", qt => qt.Type<decimal>()); Now i changed from decimal to a Value Object: Quantity. Quantity has two properties, decimal Value and Unit Unit (where Unit is an enum). I now have to map IDictionary<StocksLocation,Quantity>, how can i achieve this? Thanks in advance

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• How to call windows authentication programmatically in sharepoint?

  - by HamdiKavak

  Hi guys, Here is my scenario. When anonymous user visits site collection's default site, custom login form panel is shown. This form is a webUserControl(.ascx file) that is embeded into page as webpart. Then user enters username and password. When submit button has been clicked, authentication will be handled by code behind of custom login form panel. Here is my question. How can I call SharePoint's authentication method with the username and password that is entered by user. Simply, I want users to login through my custom login form panel because default windows authentication window is looking really bad.

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• How can I detect touch events on a UIImageView inside a deep hierarchy of UIViews?

  - by jester

  I am developing a simple game on iPhone and I started with a View based application, and through the UIViewController I am loading a custom UIView that contains some more UIViews and some UIImageViews. I want to detect touch events on some of the UIImageViews, but I wasn't able so far. I've created a second project for testing purposes and figured that UIImageViews handle touch events when the hierarchy is like : UIViewController - UIView - UIImageView, but when it's like : UIViewController - UIView - UIView - UIImageView they are not detected. Notes: - userInteractionEnabled is YES in all cases - all UIViews and UIImageViews I mention above are custom subclasses. Can you think of any reason why, when a custom UIImageView gets deeper in the view hierarchy can't receive touch events?

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• How to detect browser's protocol handlers?

  - by CJCraft.com

  I have created a custom URL protocol handler. http:// mailto:// custom:// I have registered a WinForms application to respond accordingly. This all works great. But I would like to be able to gracefully handle the case where the user doesn't have the custom URL protocol handler installed, yet. In order to be able to do this I need to be able to detect the browser's registered protocol handlers, I would assume from JavaScript. But I have been unable to find a way to poll for the information. I am hoping to find a solution to this problem. Thanks for any ideas you might be able to share.

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