I was just asked this question internally and I thought I would share with everyone:
Can I debug the OneNote add-in within Visual Studio? I tried to attach OneNote.exe but it did not stop at any breakpoint.
I wanted to let people know that you can debug one of these powertoys, here’s some notes for debugging a C# OneNote toolbar addin:
- When OneNote runs your toolbar addin your app is not running on OneNote.exe instead we are using COM and a DLL surrogate.
- The app which has the DLL surrogate is actually DllHost.exe
- You want to attach the debugger to the DllHost.exe process when you addin is running
- Since the addins normally start/stop quickly you can add MessageBox.Show command at the beginning of your code
- When you click on the button in OneNote you will see your message box popup, during this pause attach your debugger to DllHost.exe
- Debug away!
If anyone has any problems or needs help please let me know. I answered this internally and I wanted to make sure external people knew about this as well. Take care!
Note: a lot of the credit goes to David Tse who gave me these details.