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  • Have problems designing input and output for a calculator app

    - by zoul
    Hello! I am writing a button calculator. I have the code split into model, view and a controller. The model knows nothing about formatting, it is only concerned with numbers. All formatting is done in the view. The model gets its input as keypresses, each keypress is a part of an enum: typedef enum { kButtonUnknown = 0, kButtonMemoryClear = 100, kButtonMemoryPlus = 112, kButtonMemoryMinus = 109, kButtonMemoryRecall = 114, kButtonClear = 99, … }; When the user presses a button (say 1), the model receives a button code (kButtonNum1), adds the corresponding number to a string input buffer ("1") and updates the numeric output value (1.0). The controller then passes the numeric output value to the view that formats it (1). This is all plain, simple and clean, but does not really work. The problem is that when user enters a part of a number (say 0.00, going to enter 0.001), the input does not survive the way through model to view and the display says 0 instead of 0.00. I know why this happens ("0.00"::string parses to 0::double and that gets formatted as 0). What I don’t know is how to design the calculator so that the code stays clean and simple and the numbers will show up on screen exactly as the user types them. I’ve already come with some kind of solution, but that’s essentially a hack and breaks the beautiful and simple flow from the calculator model to the display. Ideas? Current solution keeps track of the calculator state. If the calculator is building a number, I take the calculator input buffer (a string) and directly set the display contents (also a string). Otherwise I take the proper path, ie. take the numeric calculator output, pass it to the view as a double and the view uses its internal formatter to create a string for the display. Example input: input | display | mode ------+---------+------------ 0 | 0 | from string 0. | 0. | from string 0.0 | 0.0 | from string 0.0+ | 0 | from number This is ugly. (1) The calculator has to expose its input buffer and state. (2) The view has to expose its display and allow setting its contents directly using a string. (3) I have to duplicate some of the formatting code to format the string I got from the calculator input buffer. If user enters 12345.000, I have to display 12,345.000 and therefore I’ve got to have a commification code for strings. Yuck.

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  • How to add Listview in tab activity?

    - by sandip armal
    I have one "SubjectTabActivity" and i need to show listview on this activity. But when i want to implement ListActivity it doesn't show listActivity. I have two(addchapter,addsubject) xml file with "SubjectTabActivity". and i need to show my database item il list view in respective xml file. but i don't understand how to do that? How to add Listactivity in TabActivity?. Please give me any reference or code. Thanks in advance.. Here is my reference code. public class MasterMainActivity extends TabActivity { LayoutInflater layoutInflater = null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.master); Intent intent=getIntent(); setResult(RESULT_OK, intent); layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); TabHost tabHost = getTabHost(); TabHost.TabSpec tab1spec = tabHost.newTabSpec("tabOneSpec"); ImageView imgView = new ImageView(this); imgView.setBackgroundResource(R.drawable.subject); tab1spec.setIndicator("Subject", imgView.getBackground()); tab1spec.setContent(new TabContentLayout()); TabHost.TabSpec tab2spec = tabHost.newTabSpec("tabTwoSpec"); tab2spec.setContent(new TabContentLayout()); ImageView imgView1 = new ImageView(this); imgView1.setBackgroundResource(R.drawable.chapter); tab2spec.setIndicator("Chapter", imgView1.getBackground()); tabHost.addTab(tab1spec); tabHost.addTab(tab2spec); } private class TabContentLayout implements TabHost.TabContentFactory { @Override public View createTabContent(String tag) { View view = null; if(tag.equals("tabOneSpec")) { try { //static final String[] FRUITS = new String[] { "Apple", "Avocado", "Banana", // "Blueberry", "Coconut", "Durian", "Guava", "Kiwifruit", //"Jackfruit", "Mango", "Olive", "Pear", "Sugar-apple" }; view = (LinearLayout) layoutInflater.inflate(R.layout.subjecttabview, null); //setListAdapter(new ArrayAdapter<String>(this, R.layout.subjecttabview,FRUITS)); } catch(Exception e) { e.printStackTrace(); } } if(tag.equals("tabTwoSpec")) { try { view = (LinearLayout) layoutInflater.inflate(R.layout.chaptertabview, null); } catch(Exception e) { e.printStackTrace(); } } return view; } } How to add ListActivity in this TabActivity

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  • How do I stack images to simulate depth using Core Animation?

    - by Jeffrey Berthiaume
    I have a series of UIImages with which I need to simulate depth. I can't use scaling because I need to be able to rotate the parent view, and the images should look like they're stacked visibly in front of each other, not on the same plane. I made a new ViewController-based project and put this in the viewDidLoad (as well as attached three 120x120 pixel images named 1.png, 2.png, and 3.png): - (void)viewDidLoad { // display image 3 UIImageView *three = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"3.png"]]; three.center = CGPointMake(160 + 60, 240 - 60); [self.view addSubview:three]; // rotate image 3 around the z axis // THIS IS INCORRECT CATransform3D theTransform = three.layer.transform; theTransform.m34 = 1.0 / -1000; three.layer.transform = theTransform; // display image 2 UIImageView *two = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"2.png"]]; two.center = CGPointMake(160, 240); [self.view addSubview:two]; // display image 1 UIImageView *one = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1.png"]]; one.center = CGPointMake(160 - 60, 240 + 60); [self.view addSubview:one]; // rotate image 3 around the z axis // THIS IS INCORRECT theTransform = one.layer.transform; theTransform.m34 = 1.0 / 1000; one.layer.transform = theTransform; // release the images [one release]; [two release]; [three release]; // rotate the parent view around the y axis theTransform = self.view.layer.transform; theTransform.m14 = 1.0 / -500; self.view.layer.transform = theTransform; [super viewDidLoad]; } I have very specific reasons why I'm not using an EAGLView and why I'm not loading the images as CALayers (i.e. why I'm using UIImageViews for each one). This is just a quick demo that I can use to work out exactly what I need in my parent application. Is there some matrix way to translate these 2d images along the z-axis so they will look like what I'm trying to represent? I've gone through the other StackOverflow articles as well as the Wikipedia references, and have not found what I'm looking for -- although I might not necessarily be using the right terms for what I'm trying to do.

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  • Problem setting row backgrounds in Android Listview

    - by zchtodd
    I have an application in which I'd like one row at a time to have a certain color. This seems to work about 95% of the time, but sometimes instead of having just one row with this color, it will allow multiple rows to have the color. Specifically, a row is set to have the "special" color when it is tapped. In rare instances, the last row tapped will retain the color despite a call to setBackgroundColor attempting to make it otherwise. private OnItemClickListener mDirectoryListener = new OnItemClickListener(){ public void onItemClick(AdapterView parent, View view, int pos, long id){ if (stdir.getStationCount() == pos) { stdir.moreStations(); return; } if (playingView != null) playingView.setBackgroundColor(Color.DKGRAY); view.setBackgroundColor(Color.MAGENTA); playingView = view; playStation(pos); } }; I have confirmed with print statements that the code setting the row to gray is always called. Can anyone imagine a reason why this code might intermittently fail? If there is a pattern or condition that causes it, I can't tell. I thought it might have something to do with the activity lifecycle setting the "playingView" variable back to null, but I can't reliably reproduce the problem by switching activities or locking the phone. private class DirectoryAdapter extends ArrayAdapter { private ArrayList<Station> items; public DirectoryAdapter(Context c, int resLayoutId, ArrayList<Station> stations){ super(c, resLayoutId, stations); this.items = stations; } public int getCount(){ return items.size() + 1; } public View getView(int position, View convertView, ViewGroup parent){ View v = convertView; LayoutInflater vi = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); if (position == this.items.size()) { v = vi.inflate(R.layout.morerow, null); return v; } Station station = this.items.get(position); v = vi.inflate(R.layout.songrow, null); if (station.playing) v.setBackgroundColor(Color.MAGENTA); else if (station.visited) v.setBackgroundColor(Color.DKGRAY); else v.setBackgroundColor(Color.BLACK); TextView title = (TextView)v.findViewById(R.id.title); title.setText(station.name); return v; } };

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  • Spring MVC, REST, and HATEOAS

    - by SingleShot
    I'm struggling with the correct way to implement Spring MVC 3.x RESTful services with HATEOAS. Consider the following constraints: I don't want my domain entities polluted with web/rest constructs. I don't want my controllers polluted with view constructs. I want to support multiple views. Currently I have a nicely put together MVC app without HATEOAS. Domain entities are pure POJOs without any view or web/rest concepts embedded. For example: class User { public String getName() {...} public String setName(String name) {...} ... } My controllers are also simple. They provide routing and status, and delegate to Spring's view resolution framework. Note my application supports JSON, XML, and HTML, yet no domain entities or controllers have embedded view information: @Controller @RequestMapping("/users") class UserController { @RequestMapping public ModelAndView getAllUsers() { List<User> users = userRepository.findAll(); return new ModelAndView("users/index", "users", users); } @RequestMapping("/{id}") public ModelAndView getUser(@PathVariable Long id) { User user = userRepository.findById(id); return new ModelAndView("users/show", "user", user); } } So, now my issue - I'm not sure of a clean way to support HATEOAS. Here's an example. Let's say when the client asks for a User in JSON format, it comes out like this: { firstName: "John", lastName: "Smith" } Let's also say that when I support HATEOAS, I want the JSON to contain a simple "self" link that the client can then use to refresh the object, delete it, or something else. It might also have a "friends" link indicating how to get the user's list of friends: { firstName: "John", lastName: "Smith", links: [ { rel: "self", ref: "http://myserver/users/1" }, { rel: "friends", ref: "http://myserver/users/1/friends" } ] } Somehow I want to attach links to my object. I feel the right place to do this is in the controller layer as the controllers all know the correct URLs. Additionally, since I support multiple views, I feel like the right thing to do is somehow decorate my domain entities in the controller before they are converted to JSON/XML/whatever in Spring's view resolution framework. One way to do this might be to wrap the POJO in question with a generic Resource class that contains a list of links. Some view tweaking would be required to crunch it into the format I want, but its doable. Unfortunately nested resources could not be wrapped in this way. Other things that come to mind include adding links to the ModelAndView, and then customizing each of Spring's out-of-the-box view resolvers to stuff links into the generated JSON/XML/etc. What I don't want is to be constantly hand-crafting JSON/XML/etc. to accommodate various links as they come and go during the course of development. Thoughts?

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  • proper fill an image larger than screen

    - by madcat
    what I wanted to achieve here is simply fit the image width to the screen on both orientations and use UIScrollView to just allow scroll vertically to see the whole image. both viewController and view are created pragmatically. the image loaded is larger than screen on both width and height. here is the related code in my viewController: - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return YES; } - (void)loadView { UIScreen *screen = [UIScreen mainScreen]; CGRect rect = [screen applicationFrame]; self.view = [[UIView alloc] initWithFrame:rect]; self.view.contentMode = UIViewContentModeScaleAspectFill; self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; UIImage *img=[[UIImage alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"image" ofType:@"png"]]; UIImageView *imgView =[[UIImageView alloc] initWithImage:img]; [img release]; imgView.contentMode = UIViewContentModeScaleAspectFill; imgView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; [self.view addSubview:imgView]; [imgView release]; } tried all combinations for both contentMode above, did not give me correct result. the most close I am getting now: I manually resize imgView in loadView, portrait mode would display correctly since app always starts with portrait mode, but in landscape mode, the width fits correctly, but image is centered vertically rather than top aligned. if I add the imgView to a scrollView, in landscape mode it looks like contentSize is not set to full image size. but when I scroll bounce I can see the image is there in full size. question: why I need to resize it manually? in landscape mode how and where I can 'move' the imgView, so imgView.frame.origin is (0,0) and works correctly with a scroll view? Thanks! UPDATE: I added: imgView.clipsToBounds = YES; and find out in landscape mode the image bounds is smaller than screen in height. so the question becomes how to have the image view keeps original ratio (thus shows the full image always) when rotated to landscape? do I need to manually resize it after rotation again?

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  • Rendering problem with UITableview

    - by Spider-Paddy
    I have a very strange problem with a UITableview within a navigation controller on the iPhone simulator. Of the cells displayed, only some are correctly rendered. They are all supposed to look the same but the majority are missing the accessory I've set, scrolling the view changes which cell has the accessory so I suspect it's some sort of cell caching happening, although the contents are correct for each cell. I also set an image as the background and that was also only displaying sporadically but I fixed that by changing cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; (which also only rendered a random cell with the background) to cell.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; I now need to fix the problem with the accessory only showing on a random cell. I tried moving the code from cellForRowAtIndex to willDisplayCell but it made no difference. I put in a log command to confirm that it is running through each frame. Basically it's a table view (UITableViewCellStyleSubtitle) that gets its info from a server & is then updated by a delegate method calling reload. Code is: -(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { NSLog(@"%@", [NSString stringWithFormat:@"Setting colours for cell %i", indexPath.row]); // Set cell background // cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; cell.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; cell.textLabel.backgroundColor = [UIColor clearColor]; cell.detailTextLabel.backgroundColor = [UIColor clearColor]; // detailTableViewAccessory is a view containing an imageview in this view's nib // i.e. nib <- view <- imageview <- image cell.accessoryView = detailTableViewAccessory; } // Called by data fetching object when done -(void)listDataTransferComplete:(ArticleListParser *)articleListParserObject { NSLog(@"Data parsed, reloading detail table"); self.currentTotalResultPages = (((articleListParserObject.currentArticleCount - 1) / 10) + 1); self.detailTableDataSource = [articleListParserObject.returnedArray copy]; // make a local copy of the returned array // Render table again with returned array data (neither of these 2 fixed it) [self.detailTableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO]; // [self.detailTableView reloadData]; // Re-enable necessary buttons (including table cells) letUserSelectRow = TRUE; [btnByName setEnabled:TRUE]; [btnByPrice setEnabled:TRUE]; // Remove please wait message NSLog(@"Removing please wait view"); [pleaseWaitViewControllerObject.view removeFromSuperview]; } I only included code that I thought was relevant, can supply more if needed. I can't test it on an iPhone yet so I don't know if it's maybe just a simulator anomaly or a bug in my code. I've always gotten good feedback from questions, any ideas?

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  • Zend Framework AjaxContext filters the results and Decorators not removable

    - by Janis Peisenieks
    Ok, since this problem has 2 parts, it will be easier to explain them together. So here goes: I am trying to remove the default decorators from these elements, since I am using a little different way of styling them. But no matter what i do, the DtDDWrapper still shows up. If I try to remove all of the decorators, all of the fields below disappear. public function newfieldAction() { $ajaxContext = $this->_helper->getHelper('AjaxContext'); $ajaxContext->addActionContext('newfield', 'html')->initContext(); $id = $this->_getParam('id', null); $id1=$id+1; $id2=$id+2; $element = new Zend_Form_Element_Text("newTitle$id1"); $element->setOptions(array('escape'=>false)); $element->setRequired(true)->setLabel('Vertiba')->removeDecorator('label'); $tinyelement=new Zend_Form_Element_Text("newName$id"); $tinyelement->setRequired(true)->setOptions(array('escape'=>false))->setLabel('Vertiba')->removeDecorator('label'); $textarea_element = new Zend_Form_Element_Textarea("newText$id2"); $textarea_element->setRequired(true)->setOptions(array('escape'=>false))->setLabel('Vertiba')->removeDecorator('label'); $this->view->descriptionField = "<td>".$textarea_element->__toString()."</td>"; $this->view->titleField = $element->__toString(); $this->view->field = $tinyelement->__toString(); $this->view->id=$id; } The context view script seams to trim my code in one way or another. When I try to put a <td> or a <table> tag in the view script, it just skips the tags. Is there a way to stop this escaping from happening? My view script: id; ?" asdfasdfasdfasd field ? titleField ? descriptionField ? id ?"remove P.S. the code formatting system is barfing at me, could someone please help me with the formatting of the code?

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  • UIButton does not respond to touch events after changing its position using setFrame

    - by Pranathi
    I have a view controller class (child) which extends from view controller class (parent). In the parent class's loadView() method I create a sub-view (named myButtonView) with two buttons (buttons are horizontally laid out in the subview) and add it to the main view. In the subclass I need to shift these two buttons up by 50pixels. So, I am shifting the buttonView by calling the setFrame method. This makes the buttons shift and render properly but they do not respond to touch events after this. Buttons work properly in the views of Parent class type. In the child class type view also, if I comment out the setFrame() call the buttons work properly. How can I shift the buttons and still make them respond to touch events? Any help is appreciated. Following is snippets of the code. In the parent class: - (void)loadView { // Some code... CGRect buttonFrameRect = CGRectMake(0,yOffset+1,screenRect.size.width,KButtonViewHeight); myButtonView = [[UIView alloc]initWithFrame:buttonFrameRect]; myButtonView.backgroundColor = [UIColor clearColor]; [self.view addSubview:myButtonView]; // some code... CGRect nxtButtonRect = CGRectMake(screenRect.size.width - 110, 5, 100, 40); myNxtButton = [UIButton buttonWithType:UIButtonTypeCustom]; [myNxtButton setTitle:@"Submit" forState:UIControlStateNormal]; myNxtButton.frame = nxtButtonRect; myNxtButton.backgroundColor = [UIColor clearColor]; [myNxtButton addTarget:self action:@selector(nextButtonPressed:) forControlEvents:UIControlEventTouchUpInside]; [myButtonView addSubview:myNxtButton]; CGRect backButtonRect = CGRectMake(10, 5, 100, 40); myBackButton = [UIButton buttonWithType:UIButtonTypeCustom]; [myBackButton setTitle:@"Back" forState:UIControlStateNormal]; myBackButton.frame = backButtonRect; myBackButton.backgroundColor = [UIColor clearColor]; [myBackButton addTarget:self action:@selector(backButtonPressed:) forControlEvents:UIControlEventTouchUpInside]; [myButtonView addSubview:myBackButton]; // Some code... } In the child class: - (void)loadView { [super loadView]; //Some code .. CGRect buttonViewRect = myButtonView.frame; buttonViewRect.origin.y = yOffset; // This is basically original yOffset + 50 [myButtonView setFrame:buttonViewRect]; yOffset += KButtonViewHeight; // Add some other view below myButtonView .. }

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  • RequestFactoryEditorDriver getting edited data after flush

    - by Deanna
    Let me start with I have a solution, but I don't really think it is elegant. So, I am looking for a cleaner way to do this. I have an EntityProxy displayed in a view panel. The view panel is a RequestFactoryEditorDriver only using display mode. The user clicks on a data element and opens a popup editor to edit a data element of the EntityProxy with a few more bits of data than is displayed in the view panel. When the user saves the element I need the view panel to update the display. I ran into a problem because the RequestFactoryEditorDriver of the popup editor flow doesn't let you get to the edited data. The driver uses the passed in context and sends it to the server. The context returned out of flush only allows a Receiver even if you cast it to the type of context you stored in the editor driver in the edit() call. It doesn't appear to send and EntityProxyChanged event either, so I couldn't listen for that and update the display view. The solution I found was to change my domain object persist to return the newly saved entity. Then create the popup editor like this editor.getSaveButtonClickHandler().addClickHandler(createSaveHandler(driver, editor)); // initialize the Driver and edit the given text. driver.initialize(rf, editor); PlayerProfileCtx ctx = rf.playerProfile(); ctx.persist().using(playerProfile).with(driver.getPaths()) .to(new Receiver<PlayerProfileProxy>(){ @Override public void onSuccess(PlayerProfileProxy profile) { editor.hide(); playerProfile = profile; viewDriver.display(playerProfile); } }); driver.edit(playerProfile, ctx); editor.centerAndShow(); Then in the save handler I just fire the context I get from the flush. While this approach works, it doesn't seem right. It would seem I should subscribe to the entitychanged event in the display view and update the entity and the view from there. Also this approach saves the complete entity, not just the changed bits, which will increase bandwidth usage. What I would think should happen, is when you flush the entity it should 'optimistically' update the rf managed version of the entity and fire the entity proxy changed event. Only reverting the entity if something went wrong in the save. The actual save should only send the changed bits. In this way there isn't a need to refetch the whole entity and send that complete data over the wire twice. Is there a better solution?

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  • IPhone iOs 5, need help getting my tab bar at the top to work

    - by Patrick
    I wanted to have the tab bar at the top. So i created a new project in XCode. Added a view and then inside that view i added (scrollbar, text and another view). See picture. What i wanted was to have my tab bar at the top. Then in the middle would be the contents from the tab bar and below it a small copyright text. See picture. No idea how to make this correctly. I have tried to create the UITabBarController on the fly and then assign it into the view at the top. (Top white space on the picture dedicated for the tab bar). Here is my code to init the MainWindow. MainWindow.h #import <UIKit/UIKit.h> @class Intro; @interface MainWindow : UIViewController @property (strong, nonatomic) IBOutlet UIScrollView *mainContentFrame; @property (strong, nonatomic) IBOutlet UIView *mainTabBarView; @property (strong, nonatomic) UITabBarController *mainTabBar; @property (nonatomic, strong) Intro *intro; // Trying to get this tab to show in the tab bar @end MainWindow.m #import "MainWindow.h" #import "Intro.h" @interface MainWindow () @end @implementation MainWindow @synthesize mainContentFrame = _mainContentFrame; @synthesize mainTabBarView = _mainTabBarView; @synthesize mainTabBar = _mainTabBar; @synthesize intro = _intro; - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization } return self; } - (void)viewDidLoad { _intro = [[Intro alloc] init]; NSArray *allViews = [[NSArray alloc] initWithObjects:_intro, nil]; [super viewDidLoad]; // Do any additional setup after loading the view. _mainTabBar = [[UITabBarController alloc] init]; [_mainTabBar setViewControllers:allViews]; [_mainTabBarView.window addSubview:_mainTabBar.tabBarController.view]; } - (void)viewDidUnload { [self setMainTabBar:nil]; [self setMainContentFrame:nil]; [self setMainContentFrame:nil]; [super viewDidUnload]; // Release any retained subviews of the main view. } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (interfaceOrientation == UIInterfaceOrientationPortrait); } @end What am i missing to get this to work? Wanted the content to end up in the scrollview so that all tabs are scrollable.

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  • The case of the phantom ADF developer (and other yarns)

    - by Chris Muir
    A few years of ADF experience means I see common mistakes made by different developers, some I regularly make myself.  This post is designed to assist beginners to Oracle JDeveloper Application Development Framework (ADF) avoid a common ADF pitfall, the case of the phantom ADF developer [add Scooby-Doo music here]. ADF Business Components - triggers, default table values and instead of views. Oracle's JDeveloper tutorials help with the A-B-Cs of ADF development, typically built on the nice 'n safe demo schema provided by with the Oracle database such as the HR demo schema. However it's not too long until ADF beginners, having built up some confidence from learning with the tutorials and vanilla demo schemas, start building ADF Business Components based upon their own existing database schema objects.  This is where unexpected problems can sneak in. The crime Developers may encounter a surprising error at runtime when editing a record they just created or updated and committed to the database, based on their own existing tables, namely the error: JBO-25014: Another user has changed the row with primary key oracle.jbo.Key[x] ...where X is the primary key value of the row at hand.  In a production environment with multiple users this error may be legit, one of the other users has updated the row since you queried it.  Yet in a development environment this error is just plain confusing.  If developers are isolated in their own database, creating and editing records they know other users can't possibly be working with, or all the other developers have gone home for the day, how is this error possible? There are no other users?  It must be the phantom ADF developer! [insert dramatic music here] The following picture is what you'll see in the Business Component Browser, and you'll receive a similar error message via an ADF Faces page: A false conclusion What can possibly cause this issue if it isn't our phantom ADF developer?  Doesn't ADF BC implement record locking, locking database records when the row is modified in the ADF middle-tier by a user?  How can our phantom ADF developer even take out a lock if this is the case?  Maybe ADF has a bug, maybe ADF isn't implementing record locking at all?  Shouldn't we see the error "JBO-26030: Failed to lock the record, another user holds the lock" as we attempt to modify the record, why do we see JBO-25014? : Let's verify that ADF is in fact issuing the correct SQL LOCK-FOR-UPDATE statement to the database. First we need to verify ADF's locking strategy.  It is determined by the Application Module's jbo.locking.mode property.  The default (as of JDev 11.1.1.4.0 if memory serves me correct) and recommended value is optimistic, and the other valid value is pessimistic. Next we need a mechanism to check that ADF is issuing the LOCK statements to the database.  We could ask DBAs to monitor locks with OEM, but optimally we'd rather not involve overworked DBAs in this process, so instead we can use the ADF runtime setting –Djbo.debugoutput=console.  At runtime this options turns on instrumentation within the ADF BC layer, which among a lot of extra detail displayed in the log window, will show the actual SQL statement issued to the database, including the LOCK statement we're looking to confirm. Setting our locking mode to pessimistic, opening the Business Components Browser of a JSF page allowing us to edit a record, say the CHARGEABLE field within a BOOKINGS record where BOOKING_NO = 1206, upon editing the record see among others the following log entries: [421] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[422] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[423] Where binding param 1: 1206  As can be seen on line 422, in fact a LOCK-FOR-UPDATE is indeed issued to the database.  Later when we commit the record we see: [441] OracleSQLBuilder: SAVEPOINT 'BO_SP'[442] OracleSQLBuilder Executing, Lock 1 DML on: BOOKINGS (Update)[443] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[444] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[445] Update binding param 1: N[446] Where binding param 2: 1206[447] BookingsView1 notify COMMIT ... [448] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [449] EntityCache close prepared statement ....and as a result the changes are saved to the database, and the lock is released. Let's see what happens when we use the optimistic locking mode, this time to change the same BOOKINGS record CHARGEABLE column again.  As soon as we edit the record we see little activity in the logs, nothing to indicate any SQL statement, let alone a LOCK has been taken out on the row. However when we save our records by issuing a commit, the following is recorded in the logs: [509] OracleSQLBuilder: SAVEPOINT 'BO_SP'[510] OracleSQLBuilder Executing doEntitySelect on: BOOKINGS (true)[511] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[512] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[513] Where binding param 1: 1205[514] OracleSQLBuilder Executing, Lock 2 DML on: BOOKINGS (Update)[515] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[516] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[517] Update binding param 1: Y[518] Where binding param 2: 1205[519] BookingsView1 notify COMMIT ... [520] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [521] EntityCache close prepared statement Again even though we're seeing the midtier delay the LOCK statement until commit time, it is in fact occurring on line 412, and released as part of the commit issued on line 419.  Therefore with either optimistic or pessimistic locking a lock is indeed issued. Our conclusion at this point must be, unless there's the unlikely cause the LOCK statement is never really hitting the database, or the even less likely cause the database has a bug, then ADF does in fact take out a lock on the record before allowing the current user to update it.  So there's no way our phantom ADF developer could even modify the record if he tried without at least someone receiving a lock error. Hmm, we can only conclude the locking mode is a red herring and not the true cause of our problem.  Who is the phantom? At this point we'll need to conclude that the error message "JBO-25014: Another user has changed" is somehow legit, even though we don't understand yet what's causing it. This leads onto two further questions, how does ADF know another user has changed the row, and what's been changed anyway? To answer the first question, how does ADF know another user has changed the row, the Fusion Guide's section 4.10.11 How to Protect Against Losing Simultaneous Updated Data , that details the Entity Object Change-Indicator property, gives us the answer: At runtime the framework provides automatic "lost update" detection for entity objects to ensure that a user cannot unknowingly modify data that another user has updated and committed in the meantime. Typically, this check is performed by comparing the original values of each persistent entity attribute against the corresponding current column values in the database at the time the underlying row is locked. Before updating a row, the entity object verifies that the row to be updated is still consistent with the current state of the database.  The guide further suggests to make this solution more efficient: You can make the lost update detection more efficient by identifying any attributes of your entity whose values you know will be updated whenever the entity is modified. Typical candidates include a version number column or an updated date column in the row.....To detect whether the row has been modified since the user queried it in the most efficient way, select the Change Indicator option to compare only the change-indicator attribute values. We now know that ADF BC doesn't use the locking mechanism at all to protect the current user against updates, but rather it keeps a copy of the original record fetched, separate to the user changed version of the record, and it compares the original record against the one in the database when the lock is taken out.  If values don't match, be it the default compare-all-columns behaviour, or the more efficient Change Indicator mechanism, ADF BC will throw the JBO-25014 error. This leaves one last question.  Now we know the mechanism under which ADF identifies a changed row, what we don't know is what's changed and who changed it? The real culprit What's changed?  We know the record in the mid-tier has been changed by the user, however ADF doesn't use the changed record in the mid-tier to compare to the database record, but rather a copy of the original record before it was changed.  This leaves us to conclude the database record has changed, but how and by who? There are three potential causes: Database triggers The database trigger among other uses, can be configured to fire PLSQL code on a database table insert, update or delete.  In particular in an insert or update the trigger can override the value assigned to a particular column.  The trigger execution is actioned by the database on behalf of the user initiating the insert or update action. Why this causes the issue specific to our ADF use, is when we insert or update a record in the database via ADF, ADF keeps a copy of the record written to the database.  However the cached record is instantly out of date as the database triggers have modified the record that was actually written to the database.  Thus when we update the record we just inserted or updated for a second time to the database, ADF compares its original copy of the record to that in the database, and it detects the record has been changed – giving us JBO-25014. This is probably the most common cause of this problem. Default values A second reason this issue can occur is another database feature, default column values.  When creating a database table the schema designer can define default values for specific columns.  For example a CREATED_BY column could be set to SYSDATE, or a flag column to Y or N.  Default values are only used by the database when a user inserts a new record and the specific column is assigned NULL.  The database in this case will overwrite the column with the default value. As per the database trigger section, it then becomes apparent why ADF chokes on this feature, though it can only specifically occur in an insert-commit-update-commit scenario, not the update-commit-update-commit scenario. Instead of trigger views I must admit I haven't double checked this scenario but it seems plausible, that of the Oracle database's instead of trigger view (sometimes referred to as instead of views).  A view in the database is based on a query, and dependent on the queries complexity, may support insert, update and delete functionality to a limited degree.  In order to support fully insertable, updateable and deletable views, Oracle introduced the instead of view, that gives the view designer the ability to not only define the view query, but a set of programmatic PLSQL triggers where the developer can define their own logic for inserts, updates and deletes. While this provides the database programmer a very powerful feature, it can cause issues for our ADF application.  On inserting or updating a record in the instead of view, the record and it's data that goes in is not necessarily the data that comes out when ADF compares the records, as the view developer has the option to practically do anything with the incoming data, including throwing it away or pushing it to tables which aren't used by the view underlying query for fetching the data. Readers are at this point reminded that this article is specifically about how the JBO-25014 error occurs in the context of 1 developer on an isolated database.  The article is not considering how the error occurs in a production environment where there are multiple users who can cause this error in a legitimate fashion.  Assuming none of the above features are the cause of the problem, and optimistic locking is turned on (this error is not possible if pessimistic locking is the default mode *and* none of the previous causes are possible), JBO-25014 is quite feasible in a production ADF application if 2 users modify the same record. At this point under project timelines pressure, the obvious fix for developers is to drop both database triggers and default values from the underlying tables.  However we must be careful that these legacy constructs aren't used and assumed to be in place by other legacy systems.  Dropping the database triggers or default value that the existing Oracle Forms  applications assumes and requires to be in place could cause unexpected behaviour and bugs in the Forms application.  Proficient software engineers would recognize such a change may require a partial or full regression test of the existing legacy system, a potentially costly and timely exercise, not ideal. Solving the mystery once and for all Luckily ADF has built in functionality to deal with this issue, though it's not a surprise, as Oracle as the author of ADF also built the database, and are fully aware of the Oracle database's feature set.  At the Entity Object attribute level, the Refresh After Insert and Refresh After Update properties.  Simply selecting these instructs ADF BC after inserting or updating a record to the database, to expect the database to modify the said attributes, and read a copy of the changed attributes back into its cached mid-tier record.  Thus next time the developer modifies the current record, the comparison between the mid-tier record and the database record match, and JBO-25014: Another user has changed" is no longer an issue. [Post edit - as per the comment from Oracle's Steven Davelaar below, as he correctly points out the above solution will not work for instead-of-triggers views as it relies on SQL RETURNING clause which is incompatible with this type of view] Alternatively you can set the Change Indicator on one of the attributes.  This will work as long as the relating column for the attribute in the database itself isn't inadvertently updated.  In turn you're possibly just masking the issue rather than solving it, because if another developer turns the Change Indicator back on the original issue will return.

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  • Web Matrix released

    - by TATWORTH
    Microsoft have now released Web Matrix (and ASP.NET MVC3 if you so inclined!) One signifcant utility is IIS Express which will replace Cassini It is worth noting that SP1 for VS2010 should be out in Q1. Links: http://www.hanselman.com/blog/ASPNETMVC3WebMatrixNuGetIISExpressAndOrchardReleasedTheMicrosoftJanuaryWebReleaseInContext.aspx http://www.hanselman.com/blog/LinkRollupNewDocumentationAndTutorialsFromWebPlatformAndTools.aspx http://arstechnica.com/microsoft/news/2011/01/microsoft-releases-free-webmatrix-web-development-tool.ars I am impressed by the copious tutorials on MVC, which I include below: Intro to ASP.NET MVC 3 onboarding series. Scott Hanselman and Rick Anderson collaboration and Mike Pope (Editor) Both C# and VB versions: Intro to ASP.NET MVC 3 Adding a Controller Adding a View Entity Framework Code-First Development Accessing your Model's Data from a Controller Adding a Create Method and Create View Adding Validation to the Model Adding a New Field to the Movie Model and Table Implementing Edit, Details and Delete Source code for this series MVC 3 Updated and new tutorials/ API Reference on MSDN Rick Anderson (Lead Programming Writer), Keith Newman and Mike Pope (Editor) ASP.NET MVC 3 Content Map ASP.NET MVC Overview MVC Framework and Application Structure Understanding MVC Application Execution Compatibility of ASP.NET Web Forms and MVC Walkthrough: Creating a Basic ASP.NET MVC Project Walkthrough: Using Forms Authentication in ASP.NET MVC Controllers and Action Methods in ASP.NET MVC Applications Using an Asynchronous Controller in ASP.NET MVC Views and UI Rendering in ASP.NET MVC Applications Rendering a Form Using HTML Helpers Passing Data in an ASP.NET MVC Application Walkthrough: Using Templated Helpers to Display Data in ASP.NET MVC Creating an ASP.NET MVC View by Calling Multiple Actions Models and Validation in ASP.NET MVC How to: Validate Model Data Using DataAnnotations Attributes Walkthrough: Using MVC View Templates How to: Implement Remote Validation in ASP.NET MVC Walkthrough: Adding AJAX Scripting Walkthrough: Organizing an Application using Areas Filtering in ASP.NET MVC Creating Custom Action Filters How to: Create a Custom Action Filter Unit Testing in ASP.NET MVC Applications Walkthrough: Using TDD with ASP.NET MVC How to: Add a Custom ASP.NET MVC Test Framework in Visual Studio ASP.NET MVC 3 Reference System.Web.Mvc System.Web.Mvc.Ajax System.Web.Mvc.Async System.Web.Mvc.Html System.Web.Mvc.Razor

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  • DirectX Unproject troubles

    - by pivotnig
    I have an orthographic projection and I try to unproject a point from screen space. Following are the view and projection matrices: var w2 = ScreenWidthInPixels/2; var h2 = ScreenHeightInPixels/2; view = Matrix.LookAtLH(new Vector3(0, 0, -1), new Vector3(0, 0, 0), Vector3.UnitY); proj = Matrix.OrthoOffCenterLH(-w2, w2, -h2, h2, 0.1f, 10f); Here is how I unproject a Point p, the point is given in screen pixels: var m = Vector3.Unproject(p, 0, 0, ScreenWidthInPixels, ScreenHeightInPixels, 0.1f, 10f, // znear and zfar view *proj); My code doesn't work, the matrix m contains only Nan. When I try to invert view * proj I get back a Matrix with only zeros. So I suspect my problem has something to do with the orthographic projection matrix. Here are my questions: Could the problem be caused by an underflow due to the large values in the OrthoOffCenterLH projection? What parameters do I have to pass for x,y,width,height in Unproject(...)? What significance has the minZ and maxZ parameter in Unproject(...)? Does it matter what I pass for p.Z in Unproject(...)?

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  • SQL SERVER – sp_describe_first_result_set New System Stored Procedure in SQL Server 2012

    - by pinaldave
    I might have said this earlier many times but I will say it again – SQL Server never stops to amaze me. Here is the example of it sp_describe_first_result_set. I stumbled upon it when I was looking for something else on BOL. This new system stored procedure did attract me to experiment with it. This SP does exactly what its names suggests – describes the first result set. Let us see very simple example of the same. Please note that this will work on only SQL Server 2012. EXEC sp_describe_first_result_set N'SELECT * FROM AdventureWorks.Sales.SalesOrderDetail', NULL, 1 GO Here is the partial resultset. Now let us take this simple example to next level and learn one more interesting detail about this function. First I will be creating a view and then we will use the same procedure over the view. USE AdventureWorks GO CREATE VIEW dbo.MyView AS SELECT [SalesOrderID] soi_v ,[SalesOrderDetailID] sodi_v ,[CarrierTrackingNumber] stn_v FROM [Sales].[SalesOrderDetail] GO Now let us execute above stored procedure with various options. You can notice I am changing the very last parameter which I am passing to the stored procedure.This option is known as for browse_information_mode. EXEC sp_describe_first_result_set N'SELECT soi_v soi, sodi_v sodi, stn_v stn FROM MyView', NULL, 0; GO EXEC sp_describe_first_result_set N'SELECT soi_v soi, sodi_v sodi, stn_v stn FROM MyView', NULL, 1; GO EXEC sp_describe_first_result_set N'SELECT soi_v soi, sodi_v sodi, stn_v stn FROM MyView', NULL, 2; GO Here is result of all the three queries together in single image for easier understanding regarding their difference. You can see that when BrowseMode is set to 1 the resultset describes the details of the original source database, schema as well source table. When BrowseMode is set to 2 the resulset describes the details of the view as the source database. I found it really really interesting that there exists system stored procedure which now describes the resultset of the output. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Stored Procedure, SQL Tips and Tricks, T SQL, Technology

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  • Adventures in MVVM &ndash; My ViewModel Base

    - by Brian Genisio's House Of Bilz
    More Adventures in MVVM First, I’d like to say: THIS IS NOT A NEW MVVM FRAMEWORK. I tend to believe that MVVM support code should be specific to the system you are building and the developers working on it.  I have yet to find an MVVM framework that does everything I want it to without doing too much.  Don’t get me wrong… there are some good frameworks out there.  I just like to pick and choose things that make sense for me.  I’d also like to add that some of these features only work in WPF.  As of Silveright 4, they don’t support binding to dynamic properties, so some of the capabilities are lost. That being said, I want to share my ViewModel base class with the world.  I have had several conversations with people about the problems I have solved using this ViewModel base.  A while back, I posted an article about some experiments with a “Rails Inspired ViewModel”.  What followed from those ideas was a ViewModel base class that I take with me and use in my projects.  It has a lot of features, all designed to reduce the friction in writing view models. I have put the code out on Codeplex under the project: ViewModelSupport. Finally, this article focuses on the ViewModel and only glosses over the View and the Model.  Without all three, you don’t have MVVM.  But this base class is for the ViewModel, so that is what I am focusing on. Features: Automatic Command Plumbing Property Change Notification Strongly Typed Property Getter/Setters Dynamic Properties Default Property values Derived Properties Automatic Method Execution Command CanExecute Change Notification Design-Time Detection What about Silverlight? Automatic Command Plumbing This feature takes the plumbing out of creating commands.  The common pattern for commands in a ViewModel is to have an Execute method as well as an optional CanExecute method.  To plumb that together, you create an ICommand Property, and set it in the constructor like so: Before public class AutomaticCommandViewModel { public AutomaticCommandViewModel() { MyCommand = new DelegateCommand(Execute_MyCommand, CanExecute_MyCommand); } public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } public DelegateCommand MyCommand { get; private set; } } With the base class, this plumbing is automatic and the property (MyCommand of type ICommand) is created for you.  The base class uses the convention that methods be prefixed with Execute_ and CanExecute_ in order to be plumbed into commands with the property name after the prefix.  You are left to be expressive with your behavior without the plumbing.  If you are wondering how CanExecuteChanged is raised, see the later section “Command CanExecute Change Notification”. After public class AutomaticCommandViewModel : ViewModelBase { public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } }   Property Change Notification One thing that always kills me when implementing ViewModels is how to make properties that notify when they change (via the INotifyPropertyChanged interface).  There have been many attempts to make this more automatic.  My base class includes one option.  There are others, but I feel like this works best for me. The common pattern (without my base class) is to create a private backing store for the variable and specify a getter that returns the private field.  The setter will set the private field and fire an event that notifies the change, only if the value has changed. Before public class PropertyHelpersViewModel : INotifyPropertyChanged { private string text; public string Text { get { return text; } set { if(text != value) { text = value; RaisePropertyChanged("Text"); } } } protected void RaisePropertyChanged(string propertyName) { var handlers = PropertyChanged; if(handlers != null) handlers(this, new PropertyChangedEventArgs(propertyName)); } public event PropertyChangedEventHandler PropertyChanged; } This way of defining properties is error-prone and tedious.  Too much plumbing.  My base class eliminates much of that plumbing with the same functionality: After public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get<string>("Text"); } set { Set("Text", value);} } }   Strongly Typed Property Getters/Setters It turns out that we can do better than that.  We are using a strongly typed language where the use of “Magic Strings” is often frowned upon.  Lets make the names in the getters and setters strongly typed: A refinement public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get(() => Text); } set { Set(() => Text, value); } } }   Dynamic Properties In C# 4.0, we have the ability to program statically OR dynamically.  This base class lets us leverage the powerful dynamic capabilities in our ecosystem. (This is how the automatic commands are implemented, BTW)  By calling Set(“Foo”, 1), you have now created a dynamic property called Foo.  It can be bound against like any static property.  The opportunities are endless.  One great way to exploit this behavior is if you have a customizable view engine with templates that bind to properties defined by the user.  The base class just needs to create the dynamic properties at runtime from information in the model, and the custom template can bind even though the static properties do not exist. All dynamic properties still benefit from the notifiable capabilities that static properties do. For any nay-sayers out there that don’t like using the dynamic features of C#, just remember this: the act of binding the View to a ViewModel is dynamic already.  Why not exploit it?  Get over it :) Just declare the property dynamically public class DynamicPropertyViewModel : ViewModelBase { public DynamicPropertyViewModel() { Set("Foo", "Bar"); } } Then reference it normally <TextBlock Text="{Binding Foo}" />   Default Property Values The Get() method also allows for default properties to be set.  Don’t set them in the constructor.  Set them in the property and keep the related code together: public string Text { get { return Get(() => Text, "This is the default value"); } set { Set(() => Text, value);} }   Derived Properties This is something I blogged about a while back in more detail.  This feature came from the chaining of property notifications when one property affects the results of another, like this: Before public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); RaisePropertyChanged("Percentage"); RaisePropertyChanged("Output"); } } public int Percentage { get { return (int)(100 * Score); } } public string Output { get { return "You scored " + Percentage + "%."; } } } The problem is: The setter for Score has to be responsible for notifying the world that Percentage and Output have also changed.  This, to me, is backwards.    It certainly violates the “Single Responsibility Principle.” I have been bitten in the rear more than once by problems created from code like this.  What we really want to do is invert the dependency.  Let the Percentage property declare that it changes when the Score Property changes. After public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public int Percentage { get { return (int)(100 * Score); } } [DependsUpon("Percentage")] public string Output { get { return "You scored " + Percentage + "%."; } } }   Automatic Method Execution This one is extremely similar to the previous, but it deals with method execution as opposed to property.  When you want to execute a method triggered by property changes, let the method declare the dependency instead of the other way around. Before public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); WhenScoreChanges(); } } public void WhenScoreChanges() { // Handle this case } } After public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public void WhenScoreChanges() { // Handle this case } }   Command CanExecute Change Notification Back to Commands.  One of the responsibilities of commands that implement ICommand – it must fire an event declaring that CanExecute() needs to be re-evaluated.  I wanted to wait until we got past a few concepts before explaining this behavior.  You can use the same mechanism here to fire off the change.  In the CanExecute_ method, declare the property that it depends upon.  When that property changes, the command will fire a CanExecuteChanged event, telling the View to re-evaluate the state of the command.  The View will make appropriate adjustments, like disabling the button. DependsUpon works on CanExecute methods as well public class CanExecuteViewModel : ViewModelBase { public void Execute_MakeLower() { Output = Input.ToLower(); } [DependsUpon("Input")] public bool CanExecute_MakeLower() { return !string.IsNullOrWhiteSpace(Input); } public string Input { get { return Get(() => Input); } set { Set(() => Input, value);} } public string Output { get { return Get(() => Output); } set { Set(() => Output, value); } } }   Design-Time Detection If you want to add design-time data to your ViewModel, the base class has a property that lets you ask if you are in the designer.  You can then set some default values that let your designer see what things might look like in runtime. Use the IsInDesignMode property public DependantPropertiesViewModel() { if(IsInDesignMode) { Score = .5; } }   What About Silverlight? Some of the features in this base class only work in WPF.  As of version 4, Silverlight does not support binding to dynamic properties.  This, in my opinion, is a HUGE limitation.  Not only does it keep you from using many of the features in this ViewModel, it also keeps you from binding to ViewModels designed in IronRuby.  Does this mean that the base class will not work in Silverlight?  No.  Many of the features outlined in this article WILL work.  All of the property abstractions are functional, as long as you refer to them statically in the View.  This, of course, means that the automatic command hook-up doesn’t work in Silverlight.  You need to plumb it to a static property in order for the Silverlight View to bind to it.  Can I has a dynamic property in SL5?     Good to go? So, that concludes the feature explanation of my ViewModel base class.  Feel free to take it, fork it, whatever.  It is hosted on CodePlex.  When I find other useful additions, I will add them to the public repository.  I use this base class every day.  It is mature, and well tested.  If, however, you find any problems with it, please let me know!  Also, feel free to suggest patches to me via the CodePlex site.  :)

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  • Ops Center Solaris 11 IPS Repository Management: Using ISO Images

    - by S Stelting
    Please join us for a live WebEx presentation of this topic on Tuesday, November 20th at 9am MDT. Details for the call are provided below: https://oracleconferencing.webex.com/oracleconferencing/j.php?ED=209834017&UID=1512096072&PW=NYTVlZTYxMzdm&RT=MiMxMQ%3D%3D Meeting password: oracle123 Call-in toll-free number: 1-866-682-4770 International numbers: http://www.intercall.com/oracle/access_numbers.htm Conference Code: 762 9343 # Security Code: 7777 # With Enterprise Manager Ops Center 12c, you can provision, patch, monitor and manage Oracle Solaris 11 instances. To do this, Ops Center creates and maintains a Solaris 11 Image Packaging System (IPS) repository on the Enterprise Controller. During the Enterprise Controller configuration, you can load repository content directly from Oracle's Support Web site and subsequently synchronize the repository as new content becomes available. Of course, you can also use Solaris 11 ISO images to create and update your Ops Center repository. There are a few excellent reasons for doing this: You're running Ops Center in disconnected mode, and don't have Internet access on your Enterprise Controller You'd rather avoid the bandwidth associated with live synchronization of a Solaris 11 package repository This demo will show you how to use Solaris 11 ISO images to set up and update your Ops Center repository. Prerequisites This tip assumes that you've already installed the Enterprise Controller on a Solaris 11 OS instance and that you're ready for post-install configuration. In addition, there are specific Ops Center and OS version requirements depending on which version of Solaris 11 you plan to install.You can get full details about the requirements in the Release Notes for Ops Center 12c update 2. Additional information is available in the Ops Center update 2 Readme document. Part 1: Using a Solaris 11 ISO Image to Create an Ops Center Repository Step 1 – Download the Solaris 11 Repository Image The Oracle Web site provides a number of download links for official Solaris 11 images. Among those links is a two-part downloadable repository image, which provides repository content for Solaris 11 SPARC and X86 architectures. In this case, I used the Solaris 11 11/11 image. First, navigate to the Oracle Web site and accept the OTN License agreement: http://www.oracle.com/technetwork/server-storage/solaris11/downloads/index.html Next, download both parts of the Solaris 11 repository image. I recommend using the Solaris 11 11/11 image, and have provided the URLs here: http://download.oracle.com/otn/solaris/11/sol-11-1111-repo-full.iso-ahttp://download.oracle.com/otn/solaris/11/sol-11-1111-repo-full.iso-b Finally, use the cat command to generate an ISO image you can use to create your repository: # cat sol-11-1111-repo-full.iso-a sol-11-1111-repo-full.iso-b > sol-11-1111-repo-full.iso The process is very similar if you plan to set up a Solaris 11.1 release in Ops Center. In that case, navigate to the Solaris 11 download page, accept the license agreement and download both parts of the Solaris 11.1 repository image. Use the cat command to create a single ISO image for Solaris 11.1 Step 2 – Mount the Solaris 11 ISO Image in your Local Filesystem Once you have created the Solaris 11 ISO file, use the mount command to attach it to your local filesystem. After the image has been mounted, you can browse the repository from the ./repo subdirectory, and use the pkgrepo command to verify that Solaris 11 recognizes the content: Step 3 – Use the Image to Create your Ops Center Repository When you have confirmed the repository is available, you can use the image to create the Enterprise Controller repository. The operation will be slightly different depending on whether you configure Ops Center for Connected or Disconnected Mode operation.For connected mode operation, specify the mounted ./repo directory in step 4.1 of the configuration wizard, replacing the default Web-based URL. Since you're synchronizing from an OS repository image, you don't need to specify a key or certificate for the operation. For disconnected mode configuration, specify the Solaris 11 directory along with the path to the disconnected mode bundle downloaded by running the Ops Center harvester script: Ops Center will run a job to import package content from the mounted ISO image. A synchronization job can take several hours to run – in my case, the job ran for 3 hours, 22 minutes on a SunFire X4200 M2 server. During the job, Ops Center performs three important tasks: Synchronizes all content from the image and refreshes the repository Updates the IPS publisher information Creates OS Provisioning profiles and policies based on the content When the job is complete, you can unmount the ISO image from your Enterprise Controller. At that time, you can view the repository contents in your Ops Center Solaris 11 library. For the Solaris 11 11/11 release, you should see 8,668 packages and patches in the contents. You should also see default deployment plans for Solaris 11 provisioning. As part of the repository import, Ops Center generates plans and profiles for desktop, small and large servers for the SPARC and X86 architecture. Part 2: Using a Solaris 11 SRU to update an Ops Center Repository It's possible to use the same approach to upgrade your Ops Center repository to a Solaris 11 Support Repository Update, or SRU. Each SRU provides packages and updates to Solaris 11 - for example, SRU 8.5 provided the packaged for Oracle VM Server for SPARC 2.2 SRUs are available for download as ISO images from My Oracle Support, under document ID 1372094.1. The document provides download links for all SRUs which have been released by Oracle for Solaris 11. SRUs are cumulative, so later versions include the packages from earlier SRUs. After downloading an ISO image for an SRU, you can mount it to your local filesystem using a mount command similar to the one shown for Solaris 11 11/11. When the ISO image is mounted to the file system, you can perform the Add Content action from the Solaris 11 Library to synchronize packages and patches from the mounted image. I used the same mount point, so the repository URL was file://mnt/repo once again: After the synchronization of an SRU is complete, you can verify its content in the Solaris 11 library using the search function. The version pattern is 0.175.0.#, where the # is the same value as the SRU. In this example, I upgraded to SRU 1. The update job ran in just under 8 minutes, and a quick search shows that 22 software components were added to the repository: It's also possible to search for "Support Repository Update" to confirm the SRU was successfully added to the repository. Details on any of the update content are available by clicking the "View Details" button under the Packages/Patches entry.

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  • Routing Issue in ASP.NET MVC 3 RC 2

    - by imran_ku07
         Introduction:             Two weeks ago, ASP.NET MVC team shipped the ASP.NET MVC 3 RC 2 release. This release includes some new features and some performance optimization. This release also fixes most of the bugs but still some minor issues are present in this release. Some of these issues are already discussed by Scott Guthrie at Update on ASP.NET MVC 3 RC2 (and a workaround for a bug in it). In addition to these issues, I have found another issue in this release regarding routing. In this article, I will show you the issue regarding routing and a simple workaround for this issue.       Description:             The easiest way to understand an issue is to reproduce it in the application. So create a MVC 2 application and a MVC 3 RC 2 application. Then in both applications, just open global.asax file and update the default route as below,     routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id1}/{id2}", // URL with parameters new { controller = "Home", action = "Index", id1 = UrlParameter.Optional, id2 = UrlParameter.Optional } // Parameter defaults );              Then just open Index View and add the following lines,    <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Home Page </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <% Html.RenderAction("About"); %> </asp:Content>             The above view will issue a child request to About action method. Now run both applications. ASP.NET MVC 2 application will run just fine. But ASP.NET MVC 3 RC 2 application will throw an exception as shown below,                  You may think that this is a routing issue but this is not the case here as both ASP.NET MVC 2 and ASP.NET MVC  3 RC 2 applications(created above) are built with .NET Framework 4.0 and both will use the same routing defined in System.Web. Something is wrong in ASP.NET MVC 3 RC 2. So after digging into ASP.NET MVC source code, I have found that the UrlParameter class in ASP.NET MVC 3 RC 2 overrides the ToString method which simply return an empty string.     public sealed class UrlParameter { public static readonly UrlParameter Optional = new UrlParameter(); private UrlParameter() { } public override string ToString() { return string.Empty; } }             In MVC 2 the ToString method was not overridden. So to quickly fix the above problem just replace UrlParameter.Optional default value with a different value other than null or empty(for example, a single white space) or replace UrlParameter.Optional default value with a new class object containing the same code as UrlParameter class have except the ToString method is not overridden (or with a overridden ToString method that return a string value other than null or empty). But by doing this you will loose the benefit of ASP.NET MVC 2 Optional URL Parameters. There may be many different ways to fix the above problem and not loose the benefit of optional parameters. Here I will create a new class MyUrlParameter with the same code as UrlParameter class have except the ToString method is not overridden. Then I will create a base controller class which contains a constructor to remove all MyUrlParameter route data parameters, same like ASP.NET MVC doing with UrlParameter route data parameters early in the request.     public class BaseController : Controller { public BaseController() { if (System.Web.HttpContext.Current.CurrentHandler is MvcHandler) { RouteValueDictionary rvd = ((MvcHandler)System.Web.HttpContext.Current.CurrentHandler).RequestContext.RouteData.Values; string[] matchingKeys = (from entry in rvd where entry.Value == MyUrlParameter.Optional select entry.Key).ToArray(); foreach (string key in matchingKeys) { rvd.Remove(key); } } } } public class HomeController : BaseController { public ActionResult Index(string id1) { ViewBag.Message = "Welcome to ASP.NET MVC!"; return View(); } public ActionResult About() { return Content("Child Request Contents"); } }     public sealed class MyUrlParameter { public static readonly MyUrlParameter Optional = new MyUrlParameter(); private MyUrlParameter() { } }     routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id1}/{id2}", // URL with parameters new { controller = "Home", action = "Index", id1 = MyUrlParameter.Optional, id2 = MyUrlParameter.Optional } // Parameter defaults );             MyUrlParameter class is a copy of UrlParameter class except that MyUrlParameter class not overrides the ToString method. Note that the default route is modified to use MyUrlParameter.Optional instead of UrlParameter.Optional. Also note that BaseController class constructor is removing MyUrlParameter parameters from the current request route data so that the model binder will not bind these parameters with action method parameters. Now just run the ASP.NET MVC 3 RC 2 application again, you will find that it runs just fine.             In case if you are curious to know that why ASP.NET MVC 3 RC 2 application throws an exception if UrlParameter class contains a ToString method which returns an empty string, then you need to know something about a feature of routing for url generation. During url generation, routing will call the ParsedRoute.Bind method internally. This method includes a logic to match the route and build the url. During building the url, ParsedRoute.Bind method will call the ToString method of the route values(in our case this will call the UrlParameter.ToString method) and then append the returned value into url. This method includes a logic after appending the returned value into url that if two continuous returned values are empty then don't match the current route otherwise an incorrect url will be generated. Here is the snippet from ParsedRoute.Bind method which will prove this statement.       if ((builder2.Length > 0) && (builder2[builder2.Length - 1] == '/')) { return null; } builder2.Append("/"); ........................................................... ........................................................... ........................................................... ........................................................... if (RoutePartsEqual(obj3, obj4)) { builder2.Append(UrlEncode(Convert.ToString(obj3, CultureInfo.InvariantCulture))); continue; }             In the above example, both id1 and id2 parameters default values are set to UrlParameter object and UrlParameter class include a ToString method that returns an empty string. That's why this route will not matched.            Summary:             In this article I showed you the issue regarding routing and also showed you how to workaround this problem. I explained this issue with an example by creating a ASP.NET MVC 2 and a ASP.NET MVC 3 RC 2 application. Finally I also explained the reason for this issue. Hopefully you will enjoy this article too.   SyntaxHighlighter.all()

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  • Installing drivers for switchable graphics

    - by Anonymous
    I recently bought a laptop that came with Windows 7 64-bit installed. I have some older (16-bit and 32-bit) software that doesn't work with 64-bit Windows, but works just fine with 32-bit. Since I also wanted to get rid of all of the pre-installed spam, I decided to wipe the hard drive and install a fresh copy of Windows 7 32-bit. I can't get the graphics cards working. This laptop uses switchable graphics, an Intel card and a Radeon card. I first tried installing this driver from Intel, which works for the Intel card. Of course, the Radeon card doesn't work with this driver and I need it for some of the newer games I have. I also tried this driver. Windows's device manager will recognize the Radeon card, but it will still use the Intel card. Also, even though that package says it contains the Intel driver, the Intel card still isn't properly recognized by Windows (leaving me with a nasty 800x600 resolution). On top of that, the Catalyst Control Center won't open (saying "The Catalyst Control Center is not supported by the driver version of your enabled graphics adapter") I tried installing HP's driver then installing Intel's driver on top of it. Device manager will then recognize both graphics cards properly. However, the laptop still uses the Intel card. The CCC still won't start (saying the same thing as before) and I can't find any of 'switching' graphics cards. Before formatting, I could right-click the desktop and click "Configure Switchable Graphics" This option hasn't been in the context menu regardless of what driver(s) I've installed. After some research, I found out that this menu entry runs the command "cli.exe Start PowerXpressHybrid" I've tried manually running this command, but I get the same unsupported message from CCC. So, does anyone know how I can get this working? I would like to be able to switch between the Intel and Radeon. But, if there's some way to disable the Intel and use only the Radeon, that would be fine I dual-boot with Linux (framebuffer uses the Intel, haven't even tried getting X set up yet) Here's the output of lspci # lspci -v | grep VGA 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) (prog-if 00 [VGA controller]) 01:00.0 VGA compatible controller: ATI Technologies Inc NI Seymour [AMD Radeon HD 6470M] (prog-if 00 [VGA controller]) The laptop is a HP Pavilion g6t-1d00. HP doesn't support installing anything but Windows 7 64-bit, so calling tech support isn't an option. Thanks for any help UPDATE: I finally got it working. After a fresh install of Windows 7, I installed the HP driver (the one linked above). Then, there's an optional Windows update I installed (don't remember the exact name, but it'll stick out). After that, graphics switching works just like it's supposed to. Moab, thanks anyways for your help

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  • Finder.app preview pane and QuickLook stretch some of my photos

    - by mcandre
    The Finder column view preview pane and QuickLook stretch many of my photos. But when I open the same photos in Preview.app, they look normal. Screenshot: For example, download this image (reaver.jpg), and view it with Finder's column view. Now view it with QuickLook. It renders correctly in every other application, so there's something going wrong in how QuickLook/Finder get the image dimensions. This problem started happening in either Mac OS X 10.8.1 or 10.8.2. Specs: Finder 10.8 QuickLook v4.0 (555.0) Mac OS X 10.8.2 MacBook Pro 2009 Also posted in Apple Discussions.

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  • Robotic Arm &ndash; Hardware

    - by Szymon Kobalczyk
    This is first in series of articles about project I've been building  in my spare time since last Summer. Actually it all began when I was researching a topic of modeling human motion kinematics in order to create gesture recognition library for Kinect. This ties heavily into motion theory of robotic manipulators so I also glanced at some designs of robotic arms. Somehow I stumbled upon this cool looking open source robotic arm: It was featured on Thingiverse and published by user jjshortcut (Jan-Jaap). Since for some time I got hooked on toying with microcontrollers, robots and other electronics, I decided to give it a try and build it myself. In this post I will describe the hardware build of the arm and in later posts I will be writing about the software to control it. Another reason to build the arm myself was the cost factor. Even small commercial robotic arms are quite expensive – products from Lynxmotion and Dagu look great but both cost around USD $300 (actually there is one cheap arm available but it looks more like a toy to me). In comparison this design is quite cheap. It uses seven hobby grade servos and even the cheapest ones should work fine. The structure is build from a set of laser cut parts connected with few metal spacers (15mm and 47mm) and lots of M3 screws. Other than that you’d only need a microcontroller board to drive the servos. So in total it comes a lot cheaper to build it yourself than buy an of the shelf robotic arm. Oh, and if you don’t like this one there are few more robotic arm projects at Thingiverse (including one by oomlout). Laser cut parts Some time ago I’ve build another robot using laser cut parts so I knew the process already. You can grab the design files in both DXF and EPS format from Thingiverse, and there are also 3D models of each part in STL. Actually the design is split into a second project for the mini servo gripper (there is also a standard servo version available but it won’t fit this arm).  I wanted to make some small adjustments, layout, and add measurements to the parts before sending it for cutting. I’ve looked at some free 2D CAD programs, and finally did all this work using QCad 3 Beta with worked great for me (I also tried LibreCAD but it didn’t work that well). All parts are cut from 4 mm thick material. Because I was worried that acrylic is too fragile and might break, I also ordered another set cut from plywood. In the end I build it from plywood because it was easier to glue (I was told acrylic requires a special glue). Btw. I found a great laser cutter service in Kraków and highly recommend it (www.ebbox.com.pl). It cost me only USD $26 for both sets ($16 acrylic + $10 plywood). Metal parts I bought all the M3 screws and nuts at local hardware store. Make sure to look for nylon lock (nyloc) nuts for the gripper because otherwise it unscrews and comes apart quickly. I couldn’t find local store with metal spacers and had to order them online (you’d need 11 x 47mm and 3 x 15mm). I think I paid less than USD $10 for all metal parts. Servos This arm uses five standards size servos to drive the arm itself, and two micro servos are used on the gripper. Author of the project used Modelcraft RS-2 Servo and Modelcraft ES-05 HT Servo. I had two Futaba S3001 servos laying around, and ordered additional TowerPro SG-5010 standard size servos and TowerPro SG90 micro servos. However it turned out that the SG90 won’t fit in the gripper so I had to replace it with a slightly smaller E-Sky EK2-0508 micro servo. Later it also turned out that Futaba servos make some strange noise while working so I swapped one with TowerPro SG-5010 which has higher torque (8kg / cm). I’ve also bought three servo extension cables. All servos cost me USD $45. Assembly The build process is not difficult but you need to think carefully about order of assembling it. You can do the base and upper arm first. Because two servos in the base are close together you need to put first with one piece of lower arm already connected before you put the second servo. Then you connect the upper arm and finally put the second piece of lower arm to hold it together. Gripper and base require some gluing so think it through too. Make sure to look closely at all the photos on Thingiverse (also other people copies) and read additional posts on jjshortcust’s blog: My mini servo grippers and completed robotic arm  Multiply the robotic arm and electronics Here is also Rob’s copy cut from aluminum My assembled arm looks like this – I think it turned out really nice: Servo controller board The last piece of hardware I needed was an electronic board that would take command from PC and drive all seven servos. I could probably use Arduino for this task, and in fact there are several Arduino servo shields available (for example from Adafruit or Renbotics).  However one problem is that most support only up to six servos, and second that their accuracy is limited by Arduino’s timer frequency. So instead I looked for dedicated servo controller and found a series of Maestro boards from Pololu. I picked the Pololu Mini Maestro 12-Channel USB Servo Controller. It has many nice features including native USB connection, high resolution pulses (0.25µs) with no jitter, built-in speed and acceleration control, and even scripting capability. Another cool feature is that besides servo control, each channel can be configured as either general input or output. So far I’m using seven channels so I still have five available to connect some sensors (for example distance sensor mounted on gripper might be useful). And last but important factor was that they have SDK in .NET – what more I could wish for! The board itself is very small – half of the size of Tic-Tac box. I picked one for about USD $35 in this store. Perhaps another good alternative would be the Phidgets Advanced Servo 8-Motor – but it is significantly more expensive at USD $87.30. The Maestro Controller Driver and Software package includes Maestro Control Center program with lets you immediately configure the board. For each servo I first figured out their move range and set the min/max limits. I played with setting the speed an acceleration values as well. Big issue for me was that there are two servos that control position of lower arm (shoulder joint), and both have to be moved at the same time. This is where the scripting feature of Pololu board turned out very helpful. I wrote a script that synchronizes position of second servo with first one – so now I only need to move one servo and other will follow automatically. This turned out tricky because I couldn’t find simple offset mapping of the move range for each servo – I had to divide it into several sub-ranges and map each individually. The scripting language is bit assembler-like but gets the job done. And there is even a runtime debugging and stack view available. Altogether I’m very happy with the Pololu Mini Maestro Servo Controller, and with this final piece I completed the build and was able to move my arm from the Meastro Control program.   The total cost of my robotic arm was: $10 laser cut parts $10 metal parts $45 servos $35 servo controller ----------------------- $100 total So here you have all the information about the hardware. In next post I’ll start talking about the software that I wrote in Microsoft Robotics Developer Studio 4. Stay tuned!

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  • What's new in ASP.Net 4.5 and VS 2012 - part 1

    - by nikolaosk
    I have downloaded .Net framework 4.5 and Visual Studio 2012 since it was released to MSDN subscribers on the 15th of August.For people that do not know about that yet please have a look at Jason Zander's excellent blog post .Since then I have been investigating the many new features that have been introduced in this release.In this post I will be looking into new features available in ASP.Net 4.5 and VS 2012.In order to follow along this post you must have Visual Studio 2012 and .Net Framework 4.5 installed in your machine.Download and install VS 2012 using this link.My machine runs on Windows 8 and Visual Studio 2012 works just fine. Please find all my posts regarding VS 2012, here .Well I have not exactly kept my promise for writing short blog posts, so I will try to keep this one short. 1) Launch VS 2012 and create a new Web Forms application by going to File - >New Web Site - > ASP.Net Web Forms Site.2) Choose an appropriate name for your web site.3) Build and run your site (CTRL+F5). Then go to View - > Source to see the HTML markup (Javascript e.t.c) that is rendered through the browser.You will see that the ASP.Net team has done a good job to make the markup cleaner and more readable. The ViewState size is significantly smaller compared to its size to earlier versions.Have a look at the picture below 4) Another thing that you must notice is that the new template makes good use of HTML 5 elements.When you view the application through the browser and then go to View Page Source you will see HTML 5 elements like nav,header,section.Have a look at the picture below  5) In VS 2012 we can browse with multiple browsers. There is a very handy dropdown that shows all the browsers available for viewing the website.Have a look at the picture below When I select the option Browse With... I see another window and I can select any of the installed browsers I want and also set the default browser. Have a look at the picture below  When I click Browse, all the selected browsers fire up and I can view the website in all of them.Have a look at the picture below There will be more posts soon looking into new features of ASP.Net 4.5 and VS 2012Hope it helps!!!

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  • The Earth at Night [Video]

    - by Jason Fitzpatrick
    This fresh video from NASA provides the clearest view of the Earth at night ever seen, thanks to the Suomi National Polar-orbiting Partnership Satellite. Check out the video and accompanying pics to see the stunning views. In daylight our big blue marble is all land, oceans and clouds. But the night – is electric. This view of Earth at night is a cloud-free view from space as acquired by the Suomi National Polar-orbiting Partnership Satellite (Suomi NPP). A joint program by NASA and NOAA, Suomi NPP captured this nighttime image by the satellite’s Visible Infrared Imaging Radiometer Suite (VIIRS). The day-night band on VIIRS detects light in a range of wavelengths from green to near infrared and uses filtering techniques to observe signals such as city lights, gas flares, and wildfires. This new image is a composite of data acquired over nine days in April and thirteen days in October 2012. It took 312 satellite orbits and 2.5 terabytes of data to get a clear shot of every parcel of land surface. This video uses the Earth at night view created by NASA’s Earth Observatory with data processed by NOAA’s National Geophysical Data Center and combined with a version of the Earth Observatory’s Blue Marble: Next Generation. Hit up the link below for the full NASA press release, including more videos and photos. How to Factory Reset Your Android Phone or Tablet When It Won’t Boot Our Geek Trivia App for Windows 8 is Now Available Everywhere How To Boot Your Android Phone or Tablet Into Safe Mode

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  • New Features in ASP.NET Web API 2 - Part I

    - by dwahlin
    I’m a big fan of ASP.NET Web API. It provides a quick yet powerful way to build RESTful HTTP services that can easily be consumed by a variety of clients. While it’s simple to get started using, it has a wealth of features such as filters, formatters, and message handlers that can be used to extend it when needed. In this post I’m going to provide a quick walk-through of some of the key new features in version 2. I’ll focus on some two of my favorite features that are related to routing and HTTP responses and cover additional features in a future post.   Attribute Routing Routing has been a core feature of Web API since it’s initial release and something that’s built into new Web API projects out-of-the-box. However, there are a few scenarios where defining routes can be challenging such as nested routes (more on that in a moment) and any situation where a lot of custom routes have to be defined. For this example, let’s assume that you’d like to define the following nested route:   /customers/1/orders   This type of route would select a customer with an Id of 1 and then return all of their orders. Defining this type of route in the standard WebApiConfig class is certainly possible, but it isn’t the easiest thing to do for people who don’t understand routing well. Here’s an example of how the route shown above could be defined:   public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "CustomerOrdersApiGet", routeTemplate: "api/customers/{custID}/orders", defaults: new { custID = 0, controller = "Customers", action = "Orders" } ); config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); GlobalConfiguration.Configuration.Formatters.Insert(0, new JsonpFormatter()); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   With attribute based routing, defining these types of nested routes is greatly simplified. To get started you first need to make a call to the new MapHttpAttributeRoutes() method in the standard WebApiConfig class (or a custom class that you may have created that defines your routes) as shown next:   public static class WebApiConfig { public static void Register(HttpConfiguration config) { // Allow for attribute based routes config.MapHttpAttributeRoutes(); config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); } } Once attribute based routes are configured, you can apply the Route attribute to one or more controller actions. Here’s an example:   [HttpGet] [Route("customers/{custId:int}/orders")] public List<Order> Orders(int custId) { var orders = _Repository.GetOrders(custId); if (orders == null) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return orders; }   This example maps the custId route parameter to the custId parameter in the Orders() method and also ensures that the route parameter is typed as an integer. The Orders() method can be called using the following route: /customers/2/orders   While this is extremely easy to use and gets the job done, it doesn’t include the default “api” string on the front of the route that you might be used to seeing. You could add “api” in front of the route and make it “api/customers/{custId:int}/orders” but then you’d have to repeat that across other attribute-based routes as well. To simply this type of task you can add the RoutePrefix attribute above the controller class as shown next so that “api” (or whatever the custom starting point of your route is) is applied to all attribute routes: [RoutePrefix("api")] public class CustomersController : ApiController { [HttpGet] [Route("customers/{custId:int}/orders")] public List<Order> Orders(int custId) { var orders = _Repository.GetOrders(custId); if (orders == null) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return orders; } }   There’s much more that you can do with attribute-based routing in ASP.NET. Check out the following post by Mike Wasson for more details.   Returning Responses with IHttpActionResult The first version of Web API provided a way to return custom HttpResponseMessage objects which were pretty easy to use overall. However, Web API 2 now wraps some of the functionality available in version 1 to simplify the process even more. A new interface named IHttpActionResult (similar to ActionResult in ASP.NET MVC) has been introduced which can be used as the return type for Web API controller actions. To return a custom response you can use new helper methods exposed through ApiController such as: Ok NotFound Exception Unauthorized BadRequest Conflict Redirect InvalidModelState Here’s an example of how IHttpActionResult and the helper methods can be used to cleanup code. This is the typical way to return a custom HTTP response in version 1:   public HttpResponseMessage Delete(int id) { var status = _Repository.DeleteCustomer(id); if (status) { return new HttpResponseMessage(HttpStatusCode.OK); } else { throw new HttpResponseException(HttpStatusCode.NotFound); } } With version 2 we can replace HttpResponseMessage with IHttpActionResult and simplify the code quite a bit:   public IHttpActionResult Delete(int id) { var status = _Repository.DeleteCustomer(id); if (status) { //return new HttpResponseMessage(HttpStatusCode.OK); return Ok(); } else { //throw new HttpResponseException(HttpStatusCode.NotFound); return NotFound(); } } You can also cleanup post (insert) operations as well using the helper methods. Here’s a version 1 post action:   public HttpResponseMessage Post([FromBody]Customer cust) { var newCust = _Repository.InsertCustomer(cust); if (newCust != null) { var msg = new HttpResponseMessage(HttpStatusCode.Created); msg.Headers.Location = new Uri(Request.RequestUri + newCust.ID.ToString()); return msg; } else { throw new HttpResponseException(HttpStatusCode.Conflict); } } This is what the code looks like in version 2:   public IHttpActionResult Post([FromBody]Customer cust) { var newCust = _Repository.InsertCustomer(cust); if (newCust != null) { return Created<Customer>(Request.RequestUri + newCust.ID.ToString(), newCust); } else { return Conflict(); } } More details on IHttpActionResult and the different helper methods provided by the ApiController base class can be found here. Conclusion Although there are several additional features available in Web API 2 that I could cover (CORS support for example), this post focused on two of my favorites features. If you have .NET 4.5.1 available then I definitely recommend checking the new features out. Additional articles that cover features in ASP.NET Web API 2 can be found here.

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  • Principles of Service-Oriented Architecture by Douwe P. van den Bos

    - by JuergenKress
    Today I hosted a session on the Principles of Service-Oriented Architecture for my colleagues at Capgemini. A very interesting session because everyone had a very clear view on the Oracle SOA Suite and a technical background. What we wanted to do was creating a common view on what a Service-Oriented Architecture is, what the benefits are that can be achieved and what is needed to create a Service-Oriented Architecture. During this very interactive session we moved from a clearly technology view on the matter (Oracle SOA Suite) to an architectural view slicing from business to technology. And this is where SOA really kicks in, because it is a philosophy. Here is the presentation on SlideShare: Principles of Service-Oriented Architecture. Read also the The Maturity of a Service-Oriented Architecture & SOA Maturity Models. Twitter & LinkedIn SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA Governance,SOA Community,Oracle SOA,Oracle BPM,BPM Community,OPN,Jürgen Kress,Douwe P. van den Bos

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