We used WPFToolKit and PresentationFramework 4.0 in our project. There are several common namespaces in both libraries (assemblies). To resolve namespace conflicts, we provided the alias WPFToolKit, which helped in coding behind (.cs files)
Now in our XAML files, as we specify an alias.
WPFToolKit DataGrid not recognized
Error: The type or name of the Controls namespace does not exist in the Microsoft.Windows namespace (do you miss the assembly reference?)
XAML namespace code
xmlns:WpfToolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit"
XAML DataGrid
<WpfToolkit:DataGrid Name="BlotterGrid" />
source share