Undefined CLR namespace

Question

I have the following:

The error says The \'clr-namespace\' URI refers to a na

Answer 1

I had similar problem when project's solution platform was set to x64. When I changed it to x86 problem went away.

Here is some explanation: http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/6379d330-f382-4b4d-a690-e89326ab4c72