Determine whether a DLL is 32-bit or 64-bit

Question

From a C# 32-bit application, In need to determine whether a given (unmanaged!) DLL file is 32-bit or 64-bit.

Does anybody have working sample code that can do this with managed code, for example by using FileStream (and not by calling Windows API functions)?

Answer 1

This looks like a duplicate of "Check if unmanaged DLL is 32 or 64-bit".

That question does provide a code solution.