PInvoke互操作技术

• c++编写

--- Person.cpp

extern "C"
{
    _declspec(dllexport) int Sum(int a, int b);
}


--- Person.h

#include "Person.h"
#include "iostream"
using namespace std;

int Sum(int a, int b)
{
    return a + b;
}

• c#调用

    class Program
    {
        [DllImport("ConsoleApplication1.dll", CallingConvention = CallingConvention.Cdecl)]
        extern static int Sum(int a, int b);

        static void Main(string[] args)
        {
            var result = Sum(10, 20);

            Console.WriteLine($"10+20={result}");

            Console.ReadLine();
        }
    }

---- output -----

10+20=30

• c#编写，c++调用

 --- main.cs
    class Program
    {
        delegate void Callback(int a);

        [DllImport("ConsoleApplication1.dll", CallingConvention = CallingConvention.Cdecl)]
        extern static void AsyncProcess(Callback callback);

        static void Main(string[] args)
        {
            AsyncProcess((i) =>
            {
                //这里回调函数哦...

                Console.WriteLine($"这是回调函数哦: {i}");
            });

            Console.ReadLine();
        }
    }

------- output -------  

这是回调函数哦: 10


--- Person.cpp

extern "C"
{
    //函数指针
    typedef void(_stdcall* PCALLBACK) (int result);
    _declspec(dllexport) void AsyncProcess(PCALLBACK ptr);
}

--- Person.h

#include "Person.h"
#include "iostream"
using namespace std;

void AsyncProcess(PCALLBACK ptr)
{
    ptr(10);  //回调C#的委托
}

环境配置

• 用vs2019创建C++的Console App，修改两个配置： 将程序导出为dll，修改成compile方式为Compile as C++ Code (/TP)