NotSupportedException when adding entity via odata on windows phone - windows-phone-7

Question

I'm using the odata client generator (DataSvcUtil.exe) in a Windows Phone 7 application. Retrieving entities and collections is fine as is updating an existing entity. But when I try to add a new entity, I get a NotSupportedException. Here's my code.
private void Button_Click(object sender, RoutedEventArgs e)
{
Drinks d =new Drink();
d.BarCode = "1234567890";
d.Description = "Test Drink";
d.Quantity = -1;
context.AddToDrinks(d);
context.BeginSaveChanges(SaveChangesOptions.Batch, OnChangesSaved, context);
}
private void OnChangesSaved(IAsyncResult result)
{
Dispatcher.BeginInvoke(() =>
{
try
{
var something = result.AsyncState;
context = result.AsyncState as DrinkTrackerModelContainer;
// Complete the save changes operation and display the response.
ShowSaveResponse("Drink Logged!", context.EndSaveChanges(result));
}
catch (DataServiceRequestException ex)
{
ShowSaveResponse("Error Logging Drink", ex.Response);
}
catch (InvalidOperationException ex)
{
ShowSaveResponse(ex.Message, null);
}
}
);
}
As soon as EndSaveChanges is called, I get the
NotSupportedException.
EDIT: I used fiddler and saw that I was in fact getting a different exception from the service. That exception data was not being shown in the debugger. Once I corrected the actual exception, the insert worked fine.

Answer 1

I think you have first chance exceptions turned on which is causing an internal exception thrown by the client library to surface as an exception. Try turning off First Chance Exceptions in the "Exceptions" menu in VS and running the app.

Answer 2

As you mentioned in your edit, the NotSupportedException was a red herring. I think that when debugging a phone app you will hit the NotSupportedException even if you have cleared the setting to break on unhandled CLR exceptions.
If you continue(F5), you'll hit an actual DataServiceRequestException exception. If it doesn't have enough information to debug it, you can follow the steps in this post to get more detailed information in the exception: http://blogs.msdn.com/b/phaniraj/archive/2008/06/18/debugging-ado-net-data-services.aspx
I ran into the same problem yesterday, and after following the steps in the blog I was able to successfully debug the problem.