In fact it's not really a problem but just a question about why things are like that :
if I do not reference System.Windows.Data, I get the error :
The type 'System.ComponentModel.IPagedCollectionView' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Windows.Data, Version=184.108.40.206, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. C:\Users\Marc\Documents\Visual Studio 2010\Projects\Repro\Repro\MainPage.xaml.cs 30 13 Repro
When I try to get the count of the items from the grid like that :
string Count = Grid.Items.Count.ToString();
Does that mean I have to add a reference to System.Windows.Data just to have the count of the Items in the grid ?