In my page I'm showing that field in a textbox like this:

<TextBox Text="{Binding Document, Mode=TwoWay}" />

If I give it a value (say "1") and save it works fine.  But if I then clear the textbox and save the value stays as "1".  How do I get around this?

Thanks

Hi Togas;

I suspect that it might be a problem with the view. I did a test with this scenario and couldn't repro this issue. In my test, I cleared the textbox, did a save, and the corresponding nullable field shows null in both my view and the database.

My suggestion to debug this is to put a breakpoint inside your SaveChangesAsync callback and inspect the EntitySaveOperation.Entities argument.

You can download my test in the link below. I'm using the NorthwindIB database that comes with every DevForce installation. In my test, I'm modifying a Customer.RowVersion field which is a nullable integer in the model.

My test is an extended version of this code sample.  http://drc.ideablade.com/xwiki/bin/view/Documentation/code-sample-add-delete-silverlight - http://drc.ideablade.com/xwiki/bin/view/Documentation/code-sample-add-delete-silverlight . I just modified the sample to include the Customer.RowVersion in the view. Everything else stays the same.

Thanks, the sample code helped.