C# DLL Load to VC++

Question

Why we cannot reference a DLL created in C# to VC++ Directly. Why we need to relate C# DLL to COM??

Vulpes · Answer

Unmanaged C++ relies on 'export tables' to call functions within a DLL. If a function appears in the DLL's export table then it can be called by outside code otherwise it cannot be. .NET DLLs don't normally use export tables but rely on metadata instead. All public methods or properties in a public class can be called by other .NET code. It is possible for a .NET DLL to include an export table which enables C++ code to call static C# methods as long as their parameters use common types. However this isn't supported from C# code and involves changing the MSIL directly so it's a technique which is seldom used in practice. Instead C++ and C# generally communicate via COM which provides a common binary interface and enables not just static methods but whole classes to be used between the two languages.