Thanks for the answer, this part is working now,
Now I am trying to use
C:\Program Files\Microsoft SDKs\Expression\Blend\.NETFramework\v4.0\Libraries\System.Windows.Interactivity.dll.
This dll comes with Microsoft Blend for .NET framework 4.0.
The dll was not viewable from the Visual Studio Reference list so I add to add it manually. Now at run time the application complains that it cannot be loaded (XamlParseException). The reference is in the project and I use the following line:
I have also declared in XAML
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
François