LINQ to Entities Domain Service

I have a domain service, derived from LinqToEntitiesDomainService<FOOEntities>

It has one method, IQueryable<Bar> GetBar(). GetBar returns a LINQ query on the entity model. The LINQ works fine in LINQPad.

In the XAML of a Silverlight thingy, I have a ListBox whose ItemsSource points to a DomainDataSource defined in the same XAML file, named dsGetBar. AutoLoad="True" on dsGetBar. I have an empty handler for the dsGetBar's LoadedData event.

I run this in VS2010. When I attach to both the WebDev.WebServer process and the browser instance, and load the page, I hit breakpoints in GetBar() and in the LoadedData handler. From this I optimistically infer that the service is getting called by the client.

In GetBar(), I call queryresults.Count, which returns 24,000 and change. My method returns fine, without throwing any exceptions.

So here's the problem:

In LoadedData, dsGetBar.Data.Count == 0. No items ever appear in the ListBox. In case my ListBox item template was broken, I tried it with a DataGrid instead. Same deal.

Is Data where the data should be? If not, where? Is ItemsSource the correct property to us开发者_如何学Pythone when you want to provide a control with a source of items?

Is there any known way to find out what is going on between the service and the client?

UPDATE

The service returns a 504 ("ReadResponse() failed: The server did not return a response for this request.") after the query method successfully completes.

UPDATE

The 504 happened because the number of records exceeded 65,535. Only 24,000-odd made it past a where clause in the LINQ (it would be 74,000 without the where clause), so this isn't even a limitation on what can go through the wire. Absurd. That number is microscopic.

I think what we've learned is that the Entity Framework isn't ready for use in software just yet.

UPDATE

...or that you should use pagers when you have to display large numbers of records in XAML.

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You can use Fiddler to see what's going on between client and server. It's a browser proxy that intercepts all browser traffic so that you can see what's happening.

I don't know what goes wrong, unfortunately.