I have a WPF solution which at some point the design viewer stopped properly rendering a custom control I wrote and the LiveCharts Cartesian Chart which is a user control, I believe. To be clear, when add either these controls to a page in the XAML Designer the controls are there but invisible - i.e. not rendered. You can select the controls and see the bounding rectangle, but you can't see the actual control. If I run the application the controls are rendered properly and usable at run time...they just don't show up in the XAML designer view.
If I create an entirely new solution/project, then both controls show up just fine in designer view. However, if I add a project to the solution in question, I get the same invisibility issue.
I have compared the solution/project's and I can not find any differences. Obviously I did something to the original solution that must have caused this, but I can not figure out what or how to fix it.
Has anyone seen this or have any ideas of what to look for to fix it?
If your WPF part is in separate assembly, then you can set its platform to AnyCPU leaving entry assembly and p/invoke ones x64. This will allow you to keep XAML editable and your external code working.