How to: Debug a Designer Load Failure
This topic shows how to debug your XAML file if it does not load in the WPF and Silverlight Designer For more information, see Troubleshooting WPF and Silverlight Designer Load Failures.
To debug a designer load failure
Open a second instance of Visual Studio.
From the Debug menu, choose Attach to Process.
The Attach To Process dialog box opens.
In the Available Processes section, select the instance of devenv.exe that is loading your XAML and click Attach.
The Visual Studio debugger attaches to the selected devenv.exe instance.
From the Debug menu, choose Exceptions.
The Exceptions dialog box opens.
In the Break when exception is list, find the Common Language Runtime Exceptions name, and then check the Thrown check box.
In the first Visual Studio instance that you are debugging, reload the XAML file.
The second instance of Visual Studio opens and displays the load exception.
You can click Stop Debugging in the second instance of Visual Studio and the first instance keeps running.