首页 > itarticle > c#加载cppdll

c#加载cppdll

admin 11月 17, 2020 0

来源与前一阵子有一个朋友请教我关于c#调用c/cpp dll 的方式

1. cpp/c 封装成dll

环境：vs2019
项目类型：新建空项目
文件类型：c/cpp
fileContent:


using namespace std;

extern "C"{
    void __declspec(dllexport) myPrint(){
        cout << "hello world" << endl;
    }
    int __declspec(dllexport) a(int b)
    {
        return b;
    }
}

项目属性：dll

2. c# 调用端

环境：vs2019
项目类型：新建空项目
文件类型：c#控制台程序
fileContent:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace hellocaller
{
    class 
    {
        
        //private static extern void myPrint();
        
        //private static extern int a(int b);


        [DllImport("kernel32.dll", EntryPoint = "LoadLibrary")]
        static extern int LoadLibrary(
            [MarshalAs(UnmanagedType.LPStr)] string lpLibFileName);

        [DllImport("kernel32.dll", EntryPoint = "GetProcAddress")]
        static extern IntPtr GetProcAddress(int hModule,
            [MarshalAs(UnmanagedType.LPStr)] string lpProcName);

        [DllImport("kernel32.dll", EntryPoint = "FreeLibrary")]
        static extern bool FreeLibrary(int hModule);

        delegate int A(int b);
        
        static void Main(string[] args)
        {
            int hModule = LoadLibrary(@"..\hello\Release\hello.dll");
            //if(hModule == 0) 
            //    return false;
            IntPtr intPtr = GetProcAddress(hModule, "a");
            A a = (A)Marshal.GetDelegateForFunctionPointer(intPtr, typeof(A));

            Console.WriteLine(a(3));
            //myPrint();
            FreeLibrary(hModule);
        }
    }
}