Add Reference to XMLSpy API
Add the application's type library as a reference in a .NET project as follows: With the .NET project open, click Project | Add Reference. Then browse for the type library, which is called XMLSpy.tlb, and is located in the XMLSpy application folder.
Then declare a variable to access the XMLSpy API:
// An instance of XMLSpy is accessed via its automation interface.
XMLSpyLib.Application XMLSpy;