c#与c++Dll 普通函数、回调函数、句柄显示图片

1、普通函数调用
2、dll内子线程回调函数
3、将dll内图片显示到c#句柄，需要使用d3d渲染技术

源码链接https://download.csdn.net/download/u011510016/77140864

c#端 ↓

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace TestWinForms {
    public partial class Form1 : Form {
        //普通函数
        [DllImport("TestDll.dll", EntryPoint = "Add", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = false, CallingConvention = CallingConvention.Cdecl)]
        public static extern int Add(int a, int b);

        //回调函数
        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        public delegate void testEventCb(int eventId, String param1);
        [DllImport("TestDll.dll", EntryPoint = "TestInit", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = false, CallingConvention = CallingConvention.Cdecl)]
        public static extern int TestInit(string param, string appid, testEventCb eventcb );

        public static testEventCb mtestCoreEventCb;
        public Form1() {
            InitializeComponent();
            mtestCoreEventCb = new testEventCb(OnTestEventCb);//委托-具体函数
            TestInit("", "", mtestCoreEventCb);
        }
        private void BtnFunc_Click(object sender, EventArgs e) {
            int a = Convert.ToInt16(textBox1.Text);
            int b = Convert.ToInt16(textBox2.Text);
            textBox3.Text = Add(a, b).ToString();

        }
        private void OnTestEventCb(int eventId, String param1) {
            
            this.Invoke((Action)delegate () {
                lblCallBack.Text = "eventId:" + eventId + " msg:" + param1;
            });
            
            
        }
    }
}

c++端 ↓

// dllmain.cpp : 定义 DLL 应用程序的入口点。
#include "pch.h"
#include 
#include

#define EXPORT extern "C" __declspec (dllexport)  
using namespace std;

EXPORT int Add(int a, int b);

typedef void (*TestEventCbFunc)(int eventID, const char* param1);
TestEventCbFunc mTestEvntCb;
EXPORT int TestInit(const char* param, const char* appid, TestEventCbFunc mCb);
void  print1();

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
                     )
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}
EXPORT int Add(int a, int b)
{
    int add_result = a + b;
    return add_result;
}

EXPORT int TestInit(const char* param, const char* appid, TestEventCbFunc mCb ) {
    mTestEvntCb = mCb;
    thread mythread1(print1);
    mythread1.detach();

    
    return 1;
}
void  print1() {
    while (true)
    {
        if (mTestEvntCb != NULL) {
            mTestEvntCb(rand()%999, "testNum");
        }
        Sleep(1000);
    }
}