Dragging a single item from a grouped datagrid will often return CollectionViewGroupInternal rather than the item

[GoogleCodeExporter]

>What steps will reproduce the problem?
1. I modified the DefaultsExample by adding a 'DataGrid with Groups' tab bound 
to the same GroupedCollectionViewSource as in the 'Listbox with groups' tab

>What is the expected output? What do you see instead?
Sometimes it would work as expected as it does in 'Listbox with Groups' but 
most of the time the dropInfo.Data was a CollectionViewGroupInternal instead of 
a GroupedItem which caused an exception. Dragging multiple items always worked 
after I modified Data.Drop.

I suspect the problem maybe the DataGrid itself.

>What version of the product are you using? 
Latest from subversion

Original issue reported on code.google.com by JezzaTi...@gmail.com on 30 Mar 2011 at 10:46

Attachments:

• Window1.xaml
• Data.cs

[GoogleCodeExporter]

I found a fix.
I updated to .net 4.0 and changed ItemsControlExtensions.GetItemContainerType 
by adding
if (itemsControl is DataGrid)
{
  return typeof (DataGridRow);
}
to the start of the method.

Original comment by JezzaTi...@gmail.com on 25 Jul 2011 at 2:02