C++项目中调用C＃DLL的三种方式

using System;
using System.Runtime.InteropServices;

[ComVisible(true)]
[Guid("YOUR-GUID-HERE")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IMyClass
{
    void MyMethod();
}

[ComVisible(true)]
[Guid("YOUR-CLASS-GUID-HERE")]
public class MyClass : IMyClass
{
    public void MyMethod()
    {
        Console.WriteLine("Hello from C#!");
    }
}

regasm MyCSharpLibrary.dll /codebase

#include <iostream>
#import "MyCSharpLibrary.tlb" // 导入类型库文件

int main()
{
    CoInitialize(NULL); // 初始化COM库

    IMyClassPtr myClass(__uuidof(MyClass)); // 创建COM对象
    myClass->MyMethod(); // 调用方法

    CoUninitialize(); // 释放COM库
    return 0;
}

// MyCppCliWrapper.h
#pragma once

using namespace System;

public ref class MyCppCliWrapper
{
public:
    void CallCSharpMethod();
};
// MyCppCliWrapper.cpp
#include "MyCppCliWrapper.h"
#include "MyCSharpLibrary.h" // 引用C#类库

void MyCppCliWrapper::CallCSharpMethod()
{
    MyCSharpLibrary::MyClass^ myClass = gcnew MyCSharpLibrary::MyClass();
    myClass->MyMethod();
}

#include <iostream>
#include "MyCppCliWrapper.h"

int main()
{
    MyCppCliWrapper^ wrapper = gcnew MyCppCliWrapper();
    wrapper->CallCSharpMethod();
    return 0;
}

using System;
using System.Runtime.InteropServices;

public class MyClass
{
    [UnmanagedCallersOnly(EntryPoint = "MyMethod")]
    public static void MyMethod()
    {
        Console.WriteLine("Hello from C#!");
    }
}

#include <iostream>
#include <windows.h>

typedef void (*MyMethodFunc)();

int main()
{
    HMODULE hModule = LoadLibrary("MyCSharpLibrary.dll");
    if (hModule)
    {
        MyMethodFunc myMethod = (MyMethodFunc)GetProcAddress(hModule, "MyMethod");
        if (myMethod)
        {
            myMethod();
        }
        FreeLibrary(hModule);
    }
    return 0;
}