Access function of c# dll from VC++ exe without using COM

First create a static library project in the same solution and turn on Common Language Runtime support. Don't turn on CLR support for the EXE project.

Add a class to the library project(.h + .cpp). Then add your necessary functions to the class and implement them only in the .cpp.

Note: You shouldn't use any .NET framework classes in .h file. For example, take a function

void ShowSomeMessageBox();

Let its implementation be,

void YourClassName::ShowSomeMessageBox()
{
   System::Windows::Forms::MessageBox::Show("Hello World!");
}

Here the declaration doesn't of the method has no .NET objects as parameters. That is you can have data types like char, int or std::string as the parameters and not System::String for example.

After this, add reference to the library project in the EXE project properties. Then add the path where you've saved the header file. Then #include the header file. And you can use ShowSomeMessage() method without exposing your whole EXE project source to CLR.

Note: This trick will only work in Visual C++.

I used Exporting functions in C#/VB.NET to native code[^] for a project that I needed to interface with a third party C# API. I created a C# wrapper DLL and inserted entry points. The DLL simply called the C# API functions.