I am dealing with some legacy code that uses Interop libraries and I am getting access violation exception from underlying COM objects without any further information. Specifically these are related to the use/access of the Range object that the docs say is only valid when the code that created is active. I am thinking of replacing the Interop based code with VSTO based code. Does anybody know if it is possible - do I get the same functionality and more importantly if VSTO itself uses Interop underneath then it defeats the purpose.


Re: Visual Studio Tools for Office Dependency of VSTO on Interop

Mohit Gupta - MSFT


With VSTO you will get the same functionality. VSTO underneath uses Interop to communicate with Excel. The differences that you will see with VSTO are isolation of your code, solution for the LCID issue in Excel PIAs. You will not need to mess around with the COM addin stuff etc.

It is not clear to me what you mean by "when the code is active". Could you give some details.