C#调用C++动态链接库(dll)的简单样例

环境：Win10、VS2017

一、生成C++动态链接库dll
1. 创建动态链接库dll

 

 

2. 新建一个C++类

 

 

 

 

3. 打开FourArith.cpp文件，添加四则运算方法

#include "pch.h"
#include "FourArith.h"

extern "C" _declspec(dllexport) double Add(double a, double b);
extern "C" _declspec(dllexport) double Sub(double a, double b);
extern "C" _declspec(dllexport) double Multi(double a, double b);
extern "C" _declspec(dllexport) double Divi(double a, double b);

double Add(double a, double b)
{
    return a + b;
}

double Sub(double a, double b)
{
    return a - b;
}

double Multi(double a, double b)
{
    return a * b;
}

double Divi(double a, double b)
{
    if (b != 0) {
        return a / b;
    }
}

 

 

二、新建C#控制台应用，调用上述生成的.dll
1. 新建C#控制台应用

 

 

2. 为了方便.dll的引用，所以将上述的.dll文件复制到当前控制台应用项目的\bin\Debug目录下。

 

3. 导入并调用.dll

class Program
    {

        [DllImport("MyDll.dll", EntryPoint = "Add", CallingConvention = CallingConvention.Cdecl)]
        public static extern double Add(double a, double b);
        [DllImport("MyDll.dll", EntryPoint = "Sub", CallingConvention = CallingConvention.Cdecl)]
        public static extern double Sub(double a, double b);
        [DllImport("MyDll.dll", EntryPoint = "Multi", CallingConvention = CallingConvention.Cdecl)]
        public static extern double Multi(double a, double b);
        [DllImport("MyDll.dll", EntryPoint = "Divi", CallingConvention = CallingConvention.Cdecl)]
        public static extern double Divi(double a, double b);

        static void Main(string[] args)
        {
            double a = 2;
            double b = 3;

            Console.WriteLine(Add(a, b));
            Console.WriteLine(Sub(a, b));
            Console.WriteLine(Multi(a, b));
            Console.WriteLine(Divi(a, b));
            Console.ReadKey();
        }
    }