Search Results

Search found 16144 results on 646 pages for 'custom identity'.

Page 161/646 | < Previous Page | 157 158 159 160 161 162 163 164 165 166 167 168  | Next Page >

  • How to use ULS in SharePoint 2010 for Custom Code Exception Logging?

    - by venkatx5
    What is ULS in SharePoint 2010? ULS stands for Unified Logging Service which captures and writes Exceptions/Logs in Log File(A Plain Text File with .log extension). SharePoint logs Each and every exceptions with ULS. SharePoint Administrators should know ULS and it's very useful when anything goes wrong. but when you ask any SharePoint 2007 Administrator to check log file then most of them will Kill you. Because read and understand the log file is not so easy. Imagine open a plain text file of 20 MB in NotePad and go thru line by line. Now Microsoft developed a tool "ULS Viewer" to view those Log files in easily readable format. This tools also helps to filter events based on exception priority. You can read on this blog to know in details about ULS Viewer . Where to get ULS Viewer? ULS Viewer is developed by Microsoft and available to download for free. URL : http://code.msdn.microsoft.com/ULSViewer/Release/ProjectReleases.aspx?ReleaseId=3308 Note: Eventhought this tool developed by Microsoft, it's not supported by Microsoft. Means you can't support for this tool from Microsoft and use it on your own Risk. By the way what's the risk in viewing Log Files?! How to use ULS in SharePoint 2010 Custom Code? ULS can be extended to use in user solutions to log exceptions. In Detail, Developer can use ULS to log his own application errors and exceptions on SharePoint Log files. So now all in Single Place (That's why it's called "Unified Logging"). Well in this article I am going to use Waldek's Code (Reference Link). However the article is core and am writing container for that (Basically how to implement the code in Detail). Let's see the steps. Open Visual Studio 2010 -> File -> New Project -> Visual C# -> Windows -> Class Library -> Name : ULSLogger (Make sure you've selected .net Framework 3.5)   In Solution Explorer Panel, Rename the Class1.cs to LoggingService.cs   Right Click on References -> Add Reference -> Under .Net tab select "Microsoft.SharePoint"   Right Click on the Project -> Properties. Select "Signing" Tab -> Check "Sign the Assembly".   In the below drop down select <New> and enter "ULSLogger", uncheck the "Protect my key with a Password" option.   Now copy the below code and paste. (Or Just refer.. :-) ) using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.SharePoint; using Microsoft.SharePoint.Administration; using System.Runtime.InteropServices; namespace ULSLogger { public class LoggingService : SPDiagnosticsServiceBase { public static string vsDiagnosticAreaName = "Venkats SharePoint Logging Service"; public static string CategoryName = "vsProject"; public static uint uintEventID = 700; // Event ID private static LoggingService _Current; public static LoggingService Current {  get   {    if (_Current == null)     {       _Current = new LoggingService();     }    return _Current;   } }private LoggingService() : base("Venkats SharePoint Logging Service", SPFarm.Local) {}protected override IEnumerable<SPDiagnosticsArea> ProvideAreas() { List<SPDiagnosticsArea> areas = new List<SPDiagnosticsArea>  {   new SPDiagnosticsArea(vsDiagnosticAreaName, new List<SPDiagnosticsCategory>    {     new SPDiagnosticsCategory(CategoryName, TraceSeverity.Medium, EventSeverity.Error)    })   }; return areas; }public static string LogErrorInULS(string errorMessage) { string strExecutionResult = "Message Not Logged in ULS. "; try  {   SPDiagnosticsCategory category = LoggingService.Current.Areas[vsDiagnosticAreaName].Categories[CategoryName];   LoggingService.Current.WriteTrace(uintEventID, category, TraceSeverity.Unexpected, errorMessage);   strExecutionResult = "Message Logged"; } catch (Exception ex) {  strExecutionResult += ex.Message; } return strExecutionResult; }public static string LogErrorInULS(string errorMessage, TraceSeverity tsSeverity) { string strExecutionResult = "Message Not Logged in ULS. "; try  {  SPDiagnosticsCategory category = LoggingService.Current.Areas[vsDiagnosticAreaName].Categories[CategoryName];  LoggingService.Current.WriteTrace(uintEventID, category, tsSeverity, errorMessage);  strExecutionResult = "Message Logged";  } catch (Exception ex)  {   strExecutionResult += ex.Message;   } return strExecutionResult;  } } }   Just build the solution and it's ready to use now. This ULS solution can be used in SharePoint Webparts or Console Application. Lets see how to use it in a Console Application. SharePoint Server 2010 must be installed in the same Server or the application must be hosted in SharPoint Server 2010 environment. The console application must be set to "x64" Platform target.   Create a New Console Application. (Visual Studio -> File -> New Project -> C# -> Windows -> Console Application) Right Click on References -> Add Reference -> Under .Net tab select "Microsoft.SharePoint" Open Program.cs add "using Microsoft.SharePoint.Administration;" Right Click on References -> Add Reference -> Under "Browse" tab select the "ULSLogger.dll" which we created first. (Path : ULSLogger\ULSLogger\bin\Debug\) Right Click on Project -> Properties -> Select "Build" Tab -> Under "Platform Target" option select "x64". Open the Program.cs and paste the below code. using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.SharePoint.Administration; using ULSLogger; namespace ULSLoggerClient {  class Program   {   static void Main(string[] args)     {     Console.WriteLine("ULS Logging Started.");     string strResult = LoggingService.LogErrorInULS("My Application is Working Fine.");      Console.WriteLine("ULS Logging Info. Result : " + strResult);     string strResult = LoggingService.LogErrorInULS("My Application got an Exception.", TraceSeverity.High);     Console.WriteLine("ULS Logging Waring Result : " + strResult);      Console.WriteLine("ULS Logging Completed.");      Console.ReadLine();     }   } } Just build the solution and execute. It'll log the message on the log file. Make sure you are using Farm Administrator User ID. You can play with Message and TraceSeverity as required. Now Open ULS Viewer -> File -> Open From -> ULS -> Select First Option to open the default ULS Log. It's Uls RealTime and will show all log entries in readable table format. Right Click on a row and select "Filter By This Item". Select "Event ID" and enter value "700" that we used in the application. Click Ok and now you'll see the Exceptions/Logs which logged by our application.   If you want to see High Priority Messages only then Click Icons except Red Cross Icon on the Toolbar. The tooltip will tell what's the icons used for.

    Read the article

  • How to configure a Web.Config file to allow custom 404 handling while still displaying on-page 500 e

    - by Mark
    To customize 404 handling and based on the hosting company's suggestion, we are currently using the following web.config setup. However, we quickly realized that with this configuration, any page error (500 error) are also getting redirected to this custom error page. How can I modify this config file so we can continue to handle 404 with custom file while still able to view on-page error? <?xml version="1.0" encoding="utf-8" ?> <configuration> <system.webServer> <httpErrors errorMode="DetailedLocalOnly" defaultPath="/Custom404.html" defaultResponseMode="ExecuteURL"> <remove statusCode="404" subStatusCode="-1" /> <error statusCode="404" prefixLanguageFilePath="" path="/Custom404.html" responseMode="ExecuteURL" /> </httpErrors> </system.webServer> <system.web> <customErrors mode="On"> <error statusCode="404" redirect="/Custom404.html" /> </customErrors> </system.web> </configuration>

    Read the article

  • I have bought a custom domain and am using it with Gmail. All My mail is being sent as spam. What can I do?

    - by Leonnears
    A while ago, I purchased my own custom domains for my websites. Before I moved them to Gmail, I just created the e-mails in my CPanel at Bluehost.com and worked from there. When the setup was like that, I could send and receive e-mail fine, and it wouldn't be marked as spam. Now I have moved these custom domains to send and receive e-mails at Gmail using Google apps. I have done everything. I have marked the domains as "Authorized" and I believe that should be enough for the mail I send with these custom e-mails is not send as spam. If it matters, I have configured my iPhone to use these custom domains with it and I'm sending all the e-mail from it. What can I do? I started doing all this today but apparently the DNS changes have already taken place. Is there something I have to do, or is it a matter of waiting 48 hours for my mail to not be marked as spam by other providers yet? EDIT: If I send mail via Gmail itself, the mail is delivered fine. If I use my iPhone however, it gets marked as spam.

    Read the article

  • How to configure a Web.Config file to allow custom 404 handling while still displaying on-page 500 error detail?

    - by Mark
    To customize 404 handling and based on the hosting company's suggestion, we are currently using the following web.config setup. However, we quickly realized that with this configuration, any page error (500 error) are also getting redirected to this custom error page. How can I modify this config file so we can continue to handle 404 with custom file while still able to view on-page error? <?xml version="1.0" encoding="utf-8" ?> <configuration> <system.webServer> <httpErrors errorMode="DetailedLocalOnly" defaultPath="/Custom404.html" defaultResponseMode="ExecuteURL"> <remove statusCode="404" subStatusCode="-1" /> <error statusCode="404" prefixLanguageFilePath="" path="/Custom404.html" responseMode="ExecuteURL" /> </httpErrors> </system.webServer> <system.web> <customErrors mode="On"> <error statusCode="404" redirect="/Custom404.html" /> </customErrors> </system.web> </configuration>

    Read the article

  • How to Auto-Increment Non-Primary Key? - SQL Server

    - by user311509
    CREATE TABLE SupplierQuote ( supplierQuoteID int identity (3504,2) CONSTRAINT supquoteid_pk PRIMARY KEY, PONumber int identity (9553,20) NOT NULL . . . CONSTRAINT ponumber_uq UNIQUE(PONumber) ); The above ddl produces an error: Msg 2744, Level 16, State 2, Line 1 Multiple identity columns specified for table 'SupplierQuote'. Only one identity column per table is allowed. How can i solve it? I want PONumber to be auto-incremented.

    Read the article

  • Custom ViewModel with MVC 2 Strongly Typed HTML Helpers return null object on Create ?

    - by Barbaros Alp
    Hi, I am having a trouble while trying to create an entity with a custom view modeled create form. Below is my custom view model for Category Creation form. public class CategoryFormViewModel { public CategoryFormViewModel(Category category, string actionTitle) { Category = category; ActionTitle = actionTitle; } public Category Category { get; private set; } public string ActionTitle { get; private set; } } and this is my user control where the UI is <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<CategoryFormViewModel>" %> <h2> <span><%= Html.Encode(Model.ActionTitle) %></span> </h2> <%=Html.ValidationSummary() %> <% using (Html.BeginForm()) {%> <p> <span class="bold block">Baslik:</span> <%=Html.TextBoxFor(model => Model.Category.Title, new { @class = "width80 txt-base" })%> </p> <p> <span class="bold block">Sira Numarasi:</span> <%=Html.TextBoxFor(model => Model.Category.OrderNo, new { @class = "width10 txt-base" })%> </p> <p> <input type="submit" class="btn-admin cursorPointer" value="Save" /> </p> <% } %> When i click on save button, it doesnt bind the category for me because of i am using custom view model and strongly typed html helpers like that <%=Html.TextBoxFor(model => Model.Category.OrderNo) %> How can i fix this ? Thanks in advance

    Read the article

  • Django custom managers - how do I return only objects created by the logged-in user?

    - by Tom Tom
    I want to overwrite the custom objects model manager to only return objects a specific user created. Admin users should still return all objects using the objects model manager. Now I have found an approach that could work. They propose to create your own middleware looking like this: #### myproject/middleware/threadlocals.py try: from threading import local except ImportError: # Python 2.3 compatibility from django.utils._threading_local import local _thread_locals = local() def get_current_user(): return getattr(_thread_locals, 'user', None) class ThreadLocals(object): """Middleware that gets various objects from the request object and saves them in thread local storage.""" def process_request(self, request): _thread_locals.user = getattr(request, 'user', None) #### end And in the Custom manager you could call the get_current_user() method to return only objects a specific user created. class UserContactManager(models.Manager): def get_query_set(self): return super(UserContactManager, self).get_query_set().filter(creator=get_current_user()) Is this a good approach to this use-case? Will this work? Or is this like "using a sledgehammer to crack a nut" ? ;-) Just using: Contact.objects.filter(created_by= user) in each view doesn`t look very neat to me. EDIT Do not use this middleware approach !!! use the approach stated by Jack M. below After a while of testing this approach behaved pretty strange and with this approach you mix up a global-state with a current request. Use the approach presented below. It is really easy and no need to hack around with the middleware. create a custom manager in your model with a function that expects the current user or any other user as an input. #in your models.py class HourRecordManager(models.Manager): def for_user(self, user): return self.get_query_set().filter(created_by=user) class HourRecord(models.Model): #Managers objects = HourRecordManager() #in vour view you can call the manager like this and get returned only the objects from the currently logged-in user. hr_set = HourRecord.objects.for_user(request.user)

    Read the article

  • How to handle custom Java exception in Flex app.

    - by mico
    Hello, we are using BlazeDS as a proxy between Flex and Java. The approach is the same as in (http://www.flexpasta.com/index.php/2008/05/16/exception-handling-with-blazeds-and-flex/) Java exception declaration: public class FlexException extends RuntimeException { private String name = 'John'; public FlexException(String message) { super(message); } public String getName() { return name; } } Then, we are throwing it: public void testMethod(String str) throws Exception { throw new FlexException("Custom exception"); } Flex part: private function faultHandler(event:FaultEvent):void { var errorMessage:ErrorMessage = event.message as ErrorMessage; trace("error++"); } and remote object is instantiated here: <mx:RemoteObject id="mySample" destination="mySample" channelSet="{cs1}" fault="faultHandler(event)" /> But in event.fault I get "Server.Processing" and event.faultString equals "There was an unhandled failure on the server. Custom exception" How can I receive the data is specified in exception props ? BlazeDS log is similar to the log that was mentioned in the comment [BlazeDS] 11:28:13.906 [DEBUG] Serializing AMF/HTTP response Version: 3 (Message #0 targetURI=/2/onStatus, responseUR|-) (Typed Object #0 ‘flex.messaging.messages.ErrorMessage’) headers = (Object #1) rootCause = null body = null correlationId = “2F1126D7-5658-BE40-E27C-7B43F3C5DCDD” faultDetail = null faultString = “Login required before authorization can proceed.” clientId = “C4F0E77C-3208-ECDD-1497-B8D070884830? timeToLive = 0.0 destination = “books” timestamp = 1.204658893906E12 extendedData = null faultCode = “Client.Authentication” messageId = “C4F0E77C-321E-6FCE-E17D-D9F1C16600A8? So the quesion is why rootClause is null? How can I get that Exception object not just a string 'Custom exception'?

    Read the article

  • How to access "Custom" or non-System TFS workitem fields using PowerShell?

    - by DaBozUK
    When using PowerShell to extract information from TFS, I find that I can get at the standard fields but not "Custom" fields. I'm not sure custom is the correct term, but for example if I look at the Process Editor in VS2008 and edit the Work Item type, there are fields such as listed below, with Name, Type and RefName: Title String System.Title State String System.State Rev Integer System.Rev Changed By String System.ChangedBy I can access these with Get-TfsItemHistory: Get-TfsItemHistory "$/path" -Version "D01/12/10~" -R | Select -exp WorkItems | Format-Table Title, State, Rev, ChangedBy -Auto So far so good. However, there are also some other fields in the WorkItem type, which I'm calling "Custom" or non-System fields, e.g.: Activated By String Microsoft.VSTS.Common.ActivatedBy Resolved By String Microsoft.VSTS.Common.ResolvedBy And the following command does not retrieve the data, just spaces. Get-TfsItemHistory "$/path" -Version "D01/12/10~" -R | Select -exp WorkItems | Format-Table ActivatedBy, ResolvedBy -Auto I've also tried the names in quotes, the fully qualified refname, but no luck. How do you access these "non-System" fields? Thanks Boz UPDATE: From Keith's answer I can get the fields I need: Get-TfsItemHistory "$/Hermes/Main" -Version "D01/12/10~" -Recurse ` | Select ChangeSetId, Comment -exp WorkItems ` | Select ChangeSetId, Comment, @{n='WI-Id'; e={$_.Id}}, Title -exp Fields ` | Where {$_.ReferenceName -eq 'Microsoft.VSTS.Common.ResolvedBy'} ` | Format-Table ChangesetId, Comment, WI-Id, Title, @{n='Resolved By'; e={$_.Value}} -Auto

    Read the article

  • Save Dialog on top of another custom dialog is behaving strangely!

    - by Raghu
    I have a save as image feature for charts in my application. The chart control is a custom user control with custom logic in them. It also has some scaling based on size, zoom etc. However, while saving them as an image I would like to give the user the option to set the size of the image (eg: 800x600 px @ 300 DPI). To do this I have created a Form with textboxes/checkboxes etc for various settings for image. One of these TextBoxes is for the file name. The file name textbox is readonly and is accompanied with a browse button which shows a SaveFileDialog when clicked. The user clicks "Save As Image" in the main form's menu. I show the ImageExportDialog using the code below: using(ImageExportDialog dlg = new ImageExportDialog()) { if(dlg.ShowDialog() == DialogResult.OK) { //get the settings selected by the user and generate the image } } In the ImageExportDialog, the user clicks on the browse button and the SaveFileDialog is shown as follows: using(SaveFileDialog dlg = new SaveFileDialog()) { if(dlg.ShowDialog() == DialogResult.OK) { txtFileName.Text = dlg.FileName; } } Now the problem is, when the user clicks on "Save" button in the SaveFileDialog, as expected the txtFileName.Text is set, but the parent custom dialog also seems to return from the ShowDialog method and the DialogResult is the same as the one for SaveFileDialog! The control then goes on to the "get the settings selected by the user and generate the image" part of the code above. Not really sure what I am doing wrong here!

    Read the article

  • Utility of List<T>.Sort() versus List<T>.OrderBy() for a member of a custom container class

    - by ccomet
    I've found myself running back through some old 3.5 framework legacy code, and found some points where there are a whole bunch of lists and dictionaries that must be updated in a synchronized fashion. I've determined that I can make this process infinitely easier to both utilize and understand by converging these into custom container classes of new custom classes. There are some points, however, where I came to concerns with organizing the contents of these new container classes by a specific inner property. For example, sorting by the ID number property of one class. As the container classes are primarily based around a generic List object, my first instinct was to write the inner classes with IComparable, and write the CompareTo method that compares the properties. This way, I can just call items.Sort() when I want to invoke the sorting. However, I've been thinking instead about using items = items.OrderBy(Func) instead. This way it is more flexible if I need to sort by any other property. Readability is better as well, since the property used for sorting will be listed in-line with the sort call rather than having to look up the IComparable code. The overall implementation feels cleaner as a result. I don't care for premature or micro optimization, but I like consistency. I find it best to stick with one kind of implementation for as many cases as it is appropriate, and use different implementations where it is necessary. Is it worth it to convert my code to use the LINQ OrderBy instead of using List.Sort? Is it a better practice to stick with the IComparable implementation for these custom containers? Are there any significant mechanical advantages offered by either path that I should be weighing the decision on? Or is their end-functionality equivalent to the point that it just becomes coder's preference?

    Read the article

  • How do I bind to a custom view in Cocoa using Xcode 4?

    - by Newt
    I'm a beginner when it comes to writing Mac apps and working with Cocoa, so please forgive my ignorance. I'm looking to create a custom view, that exposes some properties, which I can then bind to an NSObjectController. Since it's a custom view, the Bindings Inspector obviously doesn't list any of the properties I've added to the view that I can then bind to using Interface Builder. After turning to the Stackoverflow/Google for help, I've stumbled across a couple of possible solutions, but neither seem to be quite right for my situation. The first suggested creating an IBPlugin, which would then mean my bindings would be available in the Bindings Inspector. I could then bind the view to the controller using IB. Apparently IBPlugins aren't supported in Xcode 4, so that one's out the window. I'm also assuming (maybe wrongly) that IBPlugins are no longer supported because there's a better way of doing such things these days? The second option was to bind the controller to the view programmatically. I'm a bit confused as to exactly how I would achieve this. Would it require subclassing NSObjectController so I can add the calls to bind to the view? Would I need to add anything to the view to support this? Some examples I've seen say you'd need to override the bind method, and others say you don't. Also, I've noticed that some example custom views call [self exposeBinding:@"bindingName"] in the initializer. From what I gather from various sources, this is something that's related to IBPlugins and isn't something I need to do if I'm not using them. Is that correct? I've found a post on Stackoverflow here which seems to discuss something very similar to my problem, but there wasn't any clear winner as to the best answer. The last comment by noa on 12th Sept seems interesting, although they mention you should be calling exposeBinding:. Is this comment along the right track? Is the call to exposeBinding really necessary? Apologies for any dumb questions. Any help greatly appreciated.

    Read the article

  • How can I save an ASP.NET IFRAME from a custom entity's OnSave event, reliably?

    - by Forgotten Semicolon
    I have a custom ASP.NET solution deployed to the ISV directory of an MS Dynamics CRM 4.0 application. We have created a custom entity, whose data entry requires more dynamism than is possible through the form builder within CRM. To accomplish this, we have created an ASP.NET form surfaced through an IFRAME on the entity's main form. Here is how the saving functionality is currently laid out: There is an ASP.NET button control on the page that saves the entity when clicked. This button is hidden by CSS. The button click event is triggered from the CRM OnSave javascript event. The event fires and the entity is saved. Here are the issues: When the app pool is recycled, the first save (or few) may: not save be delayed (ie. the interface doesn't show an update, until the page has been refreshed after a few sec) Save and Close/New may not save For issue 1.1 and 2, what seems to be happening is that while the save event is fired for the custom ASP.NET page, the browser has moved on/refreshed the page, invalidating the request to the server. This results in the save not actually completing. Right now, this is mitigated with a kludge javascript delay loop for a few seconds after calling the button save event, inside the entity OnSave event. Is there any way to have the OnSave event wait for a callback from the IFRAME?

    Read the article

  • Entity Framework LINQ Query using Custom C# Class Method - Once yes, once no - because executing on the client or in SQL?

    - by BrooklynDev
    I have two Entity Framework 4 Linq queries I wrote that make use of a custom class method, one works and one does not: The custom method is: public static DateTime GetLastReadToDate(string fbaUsername, Discussion discussion) { return (discussion.DiscussionUserReads.Where(dur => dur.User.aspnet_User.UserName == fbaUsername).FirstOrDefault() ?? new DiscussionUserRead { ReadToDate = DateTime.Now.AddYears(-99) }).ReadToDate; } The linq query that works calls a from after a from, the equivalent of SelectMany(): from g in oc.Users.Where(u => u.aspnet_User.UserName == fbaUsername).First().Groups from d in g.Discussions select new { UnReadPostCount = d.Posts.Where(p => p.CreatedDate > DiscussionRepository.GetLastReadToDate(fbaUsername, p.Discussion)).Count() }; The query that does not work is more like a regular select: from d in oc.Discussions where d.Group.Name == "Student" select new { UnReadPostCount = d.Posts.Where(p => p.CreatedDate > DiscussionRepository.GetLastReadToDate(fbaUsername, p.Discussion)).Count(), }; The error I get is: LINQ to Entities does not recognize the method 'System.DateTime GetLastReadToDate(System.String, Discussion)' method, and this method cannot be translated into a store expression. My question is, why am I able to use my custom GetLastReadToDate() method in the first query and not the second? I suppose this has something to do with what gets executed on the db server and what gets executed on the client? These queries seem to use the GetLastReadToDate() method so similarly though, I'm wondering why would work for the first and not the second, and most importantly if there's a way to factor common query syntax like what's in the GetLastReadToDate() method into a separate location to be reused in several different places LINQ queries. Please note all these queries are sharing the same object context.

    Read the article

  • No event is firing when placing a custom data bound control in DataRepeater control in Windows forms

    - by Remo
    Hi, Custom events in a custom data bound control are not firing in DataRepeater control. When I debug it I found that the DataRepeater Control recreates the control using Activator.CreateInstance and Copies the Properties and Events. In my case copying events doesn't copy the custom events that I hooked in. For example public class MyClass : Control { public event EventHandler MyEvent; protected virtual void OnMyEvent() { if(this.MyEvent != null) { this.MyEvent(this,EventArgs.Empty); } } private int selectedIndex= -1; public int SelectedIndex { get { return this.selectedIndex; } set { if(this.selectedIndex != value) { this.selectedIndex = value; this.OnMyEvent(); } } } // // DataBinding stuff goes here // } public Form1() { InitialiseComponent(); ArrayList list = new ArrayList(); list.Add("one"); this.dataRepeater1.DataSource = list; // One Repeater MyClass test = new Myclass(); test.DataSource = GetDataTable(); this.dataRepeater1.ItemTemplate.Controls.Add(test); test.MyEvent +=new EventHandler(test_MyEvent); } // This Event should fire when selected index of Datatable is changed and is firing when placed directly in the form and not firing when place in DataRepeater control/////////////////////// private void test_MyEvent(object sender, EventArgss e) { // This event is not fired/////////////////////// } private DataTable GetDataTable() { ..// Create a data Table and return } Any help Appreciated. Thanks,

    Read the article

  • How to support comparisons for QVariant objects containing a custom type?

    - by Tyler McHenry
    According to the Qt documentation, QVariant::operator== does not work as one might expect if the variant contains a custom type: bool QVariant::operator== ( const QVariant & v ) const Compares this QVariant with v and returns true if they are equal; otherwise returns false. In the case of custom types, their equalness operators are not called. Instead the values' addresses are compared. How are you supposed to get this to behave meaningfully for your custom types? In my case, I'm storing an enumerated value in a QVariant, e.g. In a header: enum MyEnum { Foo, Bar }; Q_DECLARE_METATYPE(MyEnum); Somewhere in a function: QVariant var1 = QVariant::fromValue<MyEnum>(Foo); QVariant var2 = QVariant::fromValue<MyEnum>(Foo); assert(var1 == var2); // Fails! What do I need to do differently in order for this assertion to be true? I understand why it's not working -- each variant is storing a separate copy of the enumerated value, so they have different addresses. I want to know how I can change my approach to storing these values in variants so that either this is not an issue, or so that they do both reference the same underlying variable. It don't think it's possible for me to get around needing equality comparisons to work. The context is that I am using this enumeration as the UserData in items in a QComboBox and I want to be able to use QComboBox::findData to locate the item index corresponding to a particular enumerated value.

    Read the article

  • How to create custom MouseEvent.CLICK event in AS3 (pass parameters to function)?

    - by fromvega
    Hello, This question doesn't relate only to MouseEvent.CLICK event type but to all event types that already exist in AS3. I read a lot about custom events but until now I couldn't figure it out how to do what I want to do. I'm going to try to explain, I hope you understand: Here is a illustration of my situation: for(var i:Number; i < 10; i++){ var someVar = i; myClips[i].addEventListener(MouseEvent.CLICK, doSomething); } function doSomething(e:MouseEvent){ /* */ } But I want to be able to pass someVar as a parameter to doSomething. So I tried this: for(var i:Number; i < 10; i++){ var someVar = i; myClips[i].addEventListener(MouseEvent.CLICK, function(){ doSomething(someVar); }); } function doSomething(index){ trace(index); } This kind of works but not as I expect. Due to the function closures, when the MouseEvent.CLICK events are actually fired the for loop is already over and someVar is holding the last value, the number 9 in the example. So every click in each movie clip will call doSomething passing 9 as the parameter. And it's not what I want. I thought that creating a custom event should work, but then I couldn't find a way to fire a custom event when the MouseEvent.CLICK event is fired and pass the parameter to it. Now I don't know if it is the right answer. What should I do and how?

    Read the article

  • Custom titlebar - system titlebar being shown for a brief moment?

    - by user291701
    Hi, I've got a custom layout I want to use as the titlebar of my android app. The technique found (linked at the bottom) works, but the system titlebar is displayed before onCreate() is called. Obviously that looks pretty jarring, as for a moment the system titlebar is shown, then my custom titlebar is shown: // styles.xml <resources> <style name="MyTheme"> <item name="android:windowTitleSize">40dip</item> </style> </resources> // One of my activities, MyTheme is applied to it in the manifest. protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); setContentView(R.layout.my_activity); getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.my_custom_header); } I could always hide the system titlebar and display my own in-line perhaps with each and every layout, but, that's not very friendly. Thanks http://www.londatiga.net/it/how-to-create-custom-window-title-in-android/

    Read the article

  • Custom stream wrappers, what could they be useful for in web applications?

    - by michael
    I suppose the concept is language agnostic, but I don't know what it's called in other languages. In PHP they're Stream Wrappers. In short, a wrapper class that allows manipulation of a streamable resource (resource that can be read to/written to/seek into, such as a file, a db, an url). For example, in a template engine (a view), upon including a template file such as: include "view.wrapper://path/to/my/template/file.phtml"; my custom wrapper, declared elsewhere and associated with "view.wrapper", would first intercepts the file to replace such things as short tags (<?=) with a more verbose counterpart (<?php echo). This allows developers to use short tags in views, even if the server isn't set to allow it. It can also be applied to the preprocessing of views pseudo syntax such as {@myVar} (e.g. replacing it with $this->myVar). This is only one application of custom stream wrappers, but the feature seems powerful enough to make me think that there are others that could make life a lot simpler for developers. What have you built, or thought about building, custom stream wrappers for? where have you seen some interesting implementations? I'm particularly interested in their applications in web development.

    Read the article

  • Adding UIViews with dynamic heights iphone

    - by Andy Jacobs
    in my viewcontroller's view i need to add a couple of custom UIView's, i do that in the loadView method so in my custom uiview's drawRect method i add a couple of UILabel's. in my viewcontroller's view i need to add all those custom UIView's underneath each other but i don't know what their height is sometimes 20px, 40px, 60px, depending on the outcome of the drawRect so when i init my custom UIView i give it a frame height of lets say 50.. but when the drawRect is done and it's only 20, 50 is too much so i need to adjust the frame height but how can i determine what's the visible height of the custom UIView and where can i catch it in my viewcontroller when the custom uiview has finished his drawRect method is there some kind of autoresize and where do i catch it in my viewcontroller, so i can position the custom uiview right under neath each other.

    Read the article

  • Cross Thread Exception in PropertyChangedEvent in WPF

    - by Ashish Ashu
    I have a ListView that is binded to my custom collection. At run time , I am updating the certain properties of my entity in my custom collection in my ViewModel. At the same time , I am also doing the custom sorting in the listview. The custom sorting is applicable when I click on the any column header of the listview. For example, I am updating the current datetime on my entity on every 5 seconds and simulaneously , I am applying custom sorting based on DateTime. (The Listview is third party control). Hence I am doing two operations on my custom collection at the same time. Should I pass the dispatcher of my control in the view model and call any methods ( which updates any entity in my custom collection ) through UI dispatcher ?

    Read the article

  • Help in XPath expression

    - by Ashish Gupta
    I have an XML document which contains nodes like following:- <a class="custom">test</a> <a class="xyz"></a> I was tryng to get the nodes for which class is NOT "Custom" and I wrote an expression like following:- XmlNodeList nodeList = document.SelectNodes("//*[self::A[@class!='custom'] or self::a[@class!='custom']]"); Now, I want to get IMG tags as well and I want to add the following experession as well to the above expression:- //*[self::IMG or self::img] ...so that I get all the IMG nodes as well and any tag other than having "custom" as value in the class attribute. Any help will be appreciated. EDIT :- I tried the following and this is an invalid syntax as this returns a boolean and not any nodelist:- XmlNodeList nodeList = document.SelectNodes("//*[self::A[@class!='custom'] or self::a[@class!='custom']] && [self::IMG or self::img]");

    Read the article

  • SSH Public Key Authentication only works if active session exists before

    - by Webx10
    I have a rather strange problem with my SSH configuration. I set up my server with the help of a Remote Access Card and configured everything with a KVM viewer. So while being logged into the server via the KVM Viewer I configured SSH with only pubkey and tried to login from my local laptop. It worked fine. If I quit the KVM Session (or logout with the user in the KVM session) I cannot login via ssh anymore (pubkey denied). SSH login only works as long as the user is somewhere still logged in. Any hints what the problem might be? Console output for a failed login (all personal data exchanged): OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011 debug1: Reading configuration data /Users/mylocaluser/.ssh/config debug1: Reading configuration data /etc/ssh_config debug1: /etc/ssh_config line 20: Applying options for * debug1: /etc/ssh_config line 103: Applying options for * debug1: Connecting to 100.100.100.100 [100.100.100.100] port 12345. debug1: Connection established. debug1: identity file /Users/mylocaluser/.ssh/id_rsa type 1 debug1: identity file /Users/mylocaluser/.ssh/id_rsa-cert type -1 debug1: identity file /Users/mylocaluser/.ssh/id_dsa type -1 debug1: identity file /Users/mylocaluser/.ssh/id_dsa-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_6.2 debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 pat OpenSSH* debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-ctr [email protected] none debug1: kex: client->server aes128-ctr [email protected] none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Server host key: RSA ab:12:23:34:45:56:67:78:89:90:12:23:34:45:56:67 debug1: Host '[100.100.100.100]:12345' is known and matches the RSA host key. debug1: Found key in /Users/mylocaluser/.ssh/known_hosts:36 debug1: ssh_rsa_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: Roaming not allowed by server debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey debug1: Next authentication method: publickey debug1: Offering RSA public key: /Users/mylocaluser/.ssh/id_rsa debug1: Authentications that can continue: publickey debug1: Offering RSA public key: /Users/mylocaluser/.ssh/id_rsa2 debug1: Authentications that can continue: publickey debug1: Trying private key: /Users/mylocaluser/.ssh/id_dsa debug1: No more authentication methods to try. Permission denied (publickey). Console output for a successfull login (only possible while "active session" exists): OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011 debug1: Reading configuration data /Users/mylocaluser/.ssh/config debug1: Reading configuration data /etc/ssh_config debug1: /etc/ssh_config line 20: Applying options for * debug1: /etc/ssh_config line 103: Applying options for * debug1: Connecting to 100.100.100.100 [100.100.100.100] port 12345. debug1: Connection established. debug1: identity file /Users/mylocaluser/.ssh/id_rsa type 1 debug1: identity file /Users/mylocaluser/.ssh/id_rsa-cert type -1 debug1: identity file /Users/mylocaluser/.ssh/id_dsa type -1 debug1: identity file /Users/mylocaluser/.ssh/id_dsa-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_6.2 debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 pat OpenSSH* debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-ctr [email protected] none debug1: kex: client->server aes128-ctr [email protected] none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Server host key: RSA ab:12:23:34:45:56:67:78:89:90:12:23:34:45:56:67 debug1: Host '[100.100.100.100]:12345' is known and matches the RSA host key. debug1: Found key in /Users/mylocaluser/.ssh/known_hosts:36 debug1: ssh_rsa_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: Roaming not allowed by server debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey debug1: Next authentication method: publickey debug1: Offering RSA public key: /Users/mylocaluser/.ssh/id_rsa debug1: Server accepts key: pkalg ssh-rsa blen 279 debug1: Authentication succeeded (publickey). Authenticated to 100.100.100.100 ([100.100.100.100]:12345). debug1: channel 0: new [client-session] debug1: Requesting [email protected] debug1: Entering interactive session. debug1: Sending environment. debug1: Sending env LANG = de_DE.UTF-8 Welcome to Ubuntu 14.04.1 LTS

    Read the article

  • I created a custom (WPF) DataGridBoundColumn and get unexpected behaviour, what am I missing?

    - by aspic
    Hi, I am using a DataGrid (from Microsoft.Windows.Controls.DataGrid) to display items on and on this DataGrid I use a custom Column which extends DataGridBoundColumn. I have bound an ObservableCollection to the ItemSource of the DataGrid. Conversation is one of my own custom datatypes which a (among other things) has a boolean called active. I bound this boolean to the DataGrid as follows: DataGridActiveImageColumn test = new DataGridActiveImageColumn(); test.Header = "Active"; Binding binding1 = new Binding("Active"); test.Binding = binding1; ConversationsDataGrid.Columns.Add(test); My custom DataGridBoundColumn DataGridActiveImageColumn overrides the GenerateElement method to let it return an Image depending on whether the conversation it is called for is active or not. The code for this is: namespace Microsoft.Windows.Controls { class DataGridActiveImageColumn : DataGridBoundColumn { protected override FrameworkElement GenerateElement(DataGridCell cell, object dataItem) { // Create Image Element Image myImage = new Image(); myImage.Width = 10; bool active=false; if (dataItem is Conversation) { Conversation c = (Conversation)dataItem; active = c.Active; } BitmapImage myBitmapImage = new BitmapImage(); // BitmapImage.UriSource must be in a BeginInit/EndInit block myBitmapImage.BeginInit(); if (active) { myBitmapImage.UriSource = new Uri(@"images\active.png", UriKind.Relative); } else { myBitmapImage.UriSource = new Uri(@"images\inactive.png", UriKind.Relative); } // To save significant application memory, set the DecodePixelWidth or // DecodePixelHeight of the BitmapImage value of the image source to the desired // height or width of the rendered image. If you don't do this, the application will // cache the image as though it were rendered as its normal size rather then just // the size that is displayed. // Note: In order to preserve aspect ratio, set DecodePixelWidth // or DecodePixelHeight but not both. myBitmapImage.DecodePixelWidth = 10; myBitmapImage.EndInit(); myImage.Source = myBitmapImage; return myImage; } protected override FrameworkElement GenerateEditingElement(DataGridCell cell, object dataItem) { throw new NotImplementedException(); } } } All this works as expected, and when during the running of the program the active boolean of conversations changes, this is automatically updated in the DataGrid. However: When there are more entries on the DataGrid then fit at any one time (and vertical scrollbars are added) the behavior with respect to the column for all the conversations is strange. The conversations that are initially loaded are correct, but when I use the scrollbar of the DataGrid conversations that enter the view seems to have a random status (although more inactive than active ones, which corresponds to the actual ratio). When I scroll back up, the active images of the Conversations initially shown (before scrolling) are not correct anymore as well. When I replace my custom DataGridBoundColumn class with (for instance) DataGridCheckBoxColumn it works as intended so my extension of the DataGridBoundColumn class must be incomplete. Personally I think it has something to do with the following: From the MSDN page on the GenerateElement method (http://msdn.microsoft.com/en-us/library/system.windows.controls.datagridcolumn.generateelement%28VS.95%29.aspx): Return Value Type: System.Windows. FrameworkElement A new, read-only element that is bound to the column's Binding property value. I do return a new element (the image) but it is not bound to anything. I am not quite sure what I should do. Should I bind the Image to something? To what exactly? And why? (I have been experimenting, but was unsuccessful thus far, hence this post) Thanks in advance.

    Read the article

  • Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

    - by mortezam
    This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } }          public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } }          public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } }      public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; }              protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder.Entity<BankAccount>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("BankAccounts");         });         modelBuilder.Entity<CreditCard>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("CreditCards");         });                 } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping {     public class EntityMappingConfiguration<TEntityType> where TEntityType : class     {         public ValueConditionConfiguration Requires(string discriminator);         public void ToTable(string tableName);         public void MapInheritedProperties();     } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount();     CreditCard creditCard = new CreditCard() { CardType = 1 };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail {     [DatabaseGenerated(DatabaseGenerationOption.None)]     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>()             .Property(p => p.BillingDetailId)             .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount()      {          BillingDetailId = 1                          };     CreditCard creditCard = new CreditCard()      {          BillingDetailId = 2,         CardType = 1     };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

    Read the article

< Previous Page | 157 158 159 160 161 162 163 164 165 166 167 168  | Next Page >