From the project MarkdownEditorTest I am trying to refer to controls from another project called MarkdownEditor but am getting the Undefined CLR namespace error as seen in the image below.
Isn't the way to refer to that project something like below?
xmlns:me="clr-namespace:MarkdownEditor"
Note that each project (C#, VB, etc.) creates its own assembly.
If it's in another assembly, you need to specify the assembly name:
xmlns:me="clr-namespace:MarkdownEditor;assembly=MarkdownEditor"
Note that generally each project in a solution creates a distinct assembly. And note that a project's name can be different than the assembly name. You can see the assembly name in the project's properties (in the application tab).
Also, be aware that a project's name can be different than the assembly name. You can see the assembly name in the project's properties (in the application tab).