How to call a VSTO AddIn method from a separate C# project?

Question

I have a C# Excel Add-in project \"MyExcelAddIn\" that has a public method Foo() to do something complex. For testing purposes, the add-in also defines a toolbar button whic

Answer 1

I'm using the SendMessage Win32 API to do this. My C# Add-in creates a "NativeWindow" with a uniqe window title that the WinForm app can locate.