"The tag 'MenuItem' does not exist in XML namespace 'clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit'" error

Question

I'm getting an error trying to build a Silverlight application on a new machine. (Silverlight 4, Visual Studio 2010) This application compiles without error on four other machines.

The error is:

the tag 'MenuItem' does not exist in XML namespace 'clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit'. 

The references appear to be pointer to the correct assemblies. Has anyone else ever had this problem?

Answer 1

Another reason this issue may occur is due to missing a reference to all "three" assemblies required to use the portions of the the Toolkit controls.

Make sure you have reference to the following assemblies if attempting to use the Toolkit inputs (and assuming the themes also possibly).

System.Windows.Controls
System.Windows.Controls.Toolkit
System.Windows.Controls.Input.Toolkit

This solved the problem I was having in relation to the error.