OData and inserting (AddLink) many-to-many relationships - wpf

Question

Ok guys, this is driving me nuts. I got the following (odata) entity which represents a page structure in which every page can have any children and any parents. (basically a graph in which all nodes could be connected). In the database it's represented by a many-to-many relationship with two tables Page <-> PagePage <-> Page.
The problem is, I'm just not able to insert a new entity including a relation. The last thing I tried was:
Page page = new Page()
{
Id = Guid.NewGuid(),
Title = "New Page",
Created = DateTime.Now,
LastChanged = DateTime.Now,
IsRedirected = false,
Position = 0,
Html = "Add your HTML here.",
Parent = { parent }
};
this.Context.AddToPages(page);
this.Context.AddLink(parent, "Children", page);
parent.Children.Add(page);
this.Context.SaveChanges();
I can't think of anything else to try. Has anyone cracked this one?
Edit 1: Here's a picture from the database diagram:
Edit 2: Exception Details:
System.Data.Services.Client.DataServiceRequestException was unhandled
Message=An error occurred while processing this request.
Source=System.Data.Services.Client
StackTrace:
at System.Data.Services.Client.DataServiceContext.SaveResult.HandleBatchResponse()
at System.Data.Services.Client.DataServiceContext.SaveResult.EndRequest()
at System.Data.Services.Client.DataServiceContext.SaveChanges(SaveChangesOptions options)
at System.Data.Services.Client.DataServiceContext.SaveChanges()
at PortfolioManagementConsole.Models.PageViewModel.SaveChanges(Object parameter) in C:\Users\Daniel\documents\visual studio 2010\Projects\PortfolioManagementService\PortfolioManagementConsole\Models\PageViewModel.cs:line 59
at PortfolioManagementConsole.Common.RelayCommand.Execute(Object parameter) in C:\Users\Daniel\documents\visual studio 2010\Projects\PortfolioManagementService\PortfolioManagementConsole\Common\RelayCommand.cs:line 52
at MS.Internal.Commands.CommandHelpers.CriticalExecuteCommandSource(ICommandSource commandSource, Boolean userInitiated)
at System.Windows.Controls.Primitives.ButtonBase.OnClick()
at System.Windows.Controls.Button.OnClick()
at Telerik.Windows.Controls.RadButton.OnClick() in c:\Builds\WPF_Scrum\Release_WPF\Sources\Development\Core\Controls\Buttons\RadButton.cs:line 348
at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
at System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e)
at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
at System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)
at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.Run()
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)
at System.Windows.Application.Run()
at PortfolioManagementConsole.App.Main() in C:\Users\Daniel\documents\visual studio 2010\Projects\PortfolioManagementService\PortfolioManagementConsole\obj\x86\Debug\App.g.cs:line 0
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException: System.Data.Services.Client.DataServiceClientException
Message=<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<error xmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
<code></code>
<message xml:lang="de-CH">An error occurred while processing this request.</message>
</error>
Source=System.Data.Services.Client
StatusCode=500
StackTrace:
at System.Data.Services.Client.DataServiceContext.SaveResult.<HandleBatchResponse>d__1e.MoveNext()
InnerException:

Answer 1

Your WCF Data Services server is not returning detailed error messages and that's not helping you nail down the exact error message returned from the server. Follow these instructions to enable verbose error messages from the server :
http://blogs.msdn.com/b/phaniraj/archive/2008/06/18/debugging-ado-net-data-services.aspx .
After you've enabled this , you should be able to see the error message being thrown by the server.
From looking at your model, you need another link from the child back to the parent.
Add this line to the code right before SaveChanges :
this.Context.SetLink(page, "Parent", parent);
To help understand this better, here are some links on my blog where I detail how one works with associations using the WCF Data Services client :
1 to many associations
http://blogs.msdn.com/b/phaniraj/archive/2008/10/23/working-with-associations-in-ado-net-data-services-part-2.aspx
1 to 1 associations
http://blogs.msdn.com/b/phaniraj/archive/2008/07/02/working-with-relations-in-ado-net-data-services-beta-1.aspx