How do you debug a WPF user control in design mode?

Question

I have a wpf user control I created that contains a label. The label's foreground setting changes based on some code that checks a number of conditions. The label in my control is displaying the wrong color at design time but I cannot figure out how to debug my user control at design time so that I can have it catch breakpoints (and thus figure out where my logic is flawed). The color on the control is correct at run-time, it is only at design time that it is displayed incorrectly.

Answer 1

Here are the steps to debug a control at design time:

• Start a second instance of Visual Studio
• Attach to the first instance from the Debug menu (or in VS2022, attach to the WPFSurface)
• In the second instance, open the source code of your control
• Set breakpoints at appropriate locations
• In the first VS instance, reload the designer

Note that this technique isn't limited to controls; you can also use it to debug VS extensions, or anything that executes within Visual Studio.