c#调用c++的dll

制作c++的dll

// MyCppDll.cpp : 定义 DLL 应用程序的导出函数。



//　这一句必须

#include "stdafx.h"

//　导入自己想要的头文件

#include <windows.h>



//　为函数加入以下声明即可导出：extern "C" extern __declspec(dllexport) 

//	另外，加入以上声明后函數調用約定默认为“Cdecl”，若要强制指定为，请在函数的返回类型之后加入“__stdcall”关键字

extern "C" extern __declspec(dllexport)  LPCWSTR __stdcall Hello(LPCWSTR lpTitle,LPCWSTR lpContent)

{

	MessageBox(NULL,lpContent,lpTitle,0);

	return lpContent;

}











//　定义 DLL 应用程序的入口点。

//　比如当dll刚被载入至内存或卸载时可以做一些事

BOOL APIENTRY DllMain( HMODULE hModule,

	DWORD  ul_reason_for_call,

	LPVOID lpReserved

	)

{

	switch (ul_reason_for_call)

	{

	case DLL_PROCESS_ATTACH:

		Hello(L"",L"DLL_PROCESS_ATTACH");

		break;

	case DLL_THREAD_ATTACH:

		Hello(L"",L"DLL_THREAD_ATTACH");

		break;

	case DLL_THREAD_DETACH:

		Hello(L"",L"DLL_THREAD_DETACH");

		break;

	case DLL_PROCESS_DETACH:

		Hello(L"",L"DLL_PROCESS_DETACH");

		break;

	}



	return TRUE;

}

写c#

using System;

using System.Runtime.InteropServices;





namespace MyCsharpConsoleApplication

{

    class Program

    {

        [DllImport("MyCppDll", CallingConvention = CallingConvention.StdCall)]

        extern static string Hello(string title, string content);



        static void Main()

        {

            var ret = Hello(@"hello你好".ToAnsi(), @"theraphy大叮当".ToAnsi());

            Console.WriteLine(ret);

        }

    }



    static class Helper

    {

        /// <summary>

        /// 将Unicode字符串转换成多字节字符串

        /// </summary>

        /// <param name="content"></param>

        /// <returns></returns>

        public static string ToAnsi(this string content)

        {

            return System.Text.Encoding.Default.GetString(System.Text.Encoding.Unicode.GetBytes(content));

        }

    }

}

也可以直接声明Unicode编码传递

using System;

using System.Runtime.InteropServices;





namespace MyCsharpConsoleApplication

{

    class Program

    {

        [DllImport("MyCppDll", CallingConvention = CallingConvention.StdCall,CharSet = CharSet.Unicode)]

        extern static string Hello(string title, string content);



        static void Main()

        {

            var ret = Hello(@"hello你好", @"theraphy大叮当");

            Console.WriteLine(ret);

        }

    }

}

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