ephr4321

You get an overflow exception because you need to change hWnd.SendMessage(msg, InteropUtil.NumberOfFileChars, unchecked((uint)buffer)); to hWnd.SendMessage(msg, InteropUtil.NumberOfFileChars, unchecked((ulong)buffer)); Obviously change the function signature too.

Regarding compiling it - The project as is get compiled with VS2008. After compiling it you can copy the res1.res into the obj/debug (or obj/release etc...) path Also remove from...