WPF: VS2012 designer shows "The component 'XXX' does not have a resource identified by the URI YYY"

wpf visual-studio designer

It is possible that the control's .g.cs or .g.i.cs file has been corrupted. Try to clean, close visual studio and restart it. I think that helped for me in several cases especially when I copy paste controls from one solution to another.

wpf visual-studio designer

Just delete subfolders in

%LOCALAPPDATA%\Microsoft\VisualStudio\12.0\Designer\ShadowCache

wpf visual-studio designer

If you refactor a UserControl down a lower level project that the UserControl was previously referencing then you will see this error.

Removing the assembly reference from the namespace fixes the issue.

<UserControl xmlns:ui="clr-namespace:MyCompany.Core.UI;assembly=MyCompany.Core.UI"

should be

<UserControl xmlns:ui="clr-namespace:MyCompany.Core.UI"

The designer is not smart enough to highlight this.