C#调用C生成DLL文件

来源：互联网发布：知乎轩辕剑编辑：程序博客网时间：2024/05/16 01:35

环境: VS2010, Win7

1. 添加新项目->Win32项目输入名称:CSInvokeCDll

2.应用程序设置中选择DLL然后点击完成

3 在CSharpInvokeCPP.CPP中书写C代码

#include "stdafx.h"#include "malloc.h"#include "userinfo.h"typedef struct {char name[32];int age;} User; UserInfo* userInfo;extern "C" __declspec(dllexport) int Add(int x, int y) { return x + y; }extern "C" __declspec(dllexport) int Sub(int x, int y) { return x - y; }extern "C" __declspec(dllexport) int Multiply(int x, int y) { return x * y; }extern "C" __declspec(dllexport) int Divide(int x, int y) { return x / y; }extern "C" __declspec(dllexport) int Sum(int * parr, int length){int sum = 0;if(parr == NULL)return sum;for(int i = 0; i < length; i++){sum += *parr++;}return sum;}extern "C" __declspec(dllexport) User* Create(char* name, int age)    {   User* user = (User*)malloc(sizeof(User))strcpy(user->name, name);user->age = age;return user; }

4 添加C#控制台应用程序, 并命名为CSInvokeCPP

5 创建C#对CPP 生成Dll的引用类CPPAdapter

public class CPPAdapter    {        [DllImport("CSharpInvokeCPP.CPPDemo.dll")]        public static extern int Add(int x, int y);        [DllImport("CSharpInvokeCPP.CPPDemo.dll")]        public static extern int Sub(int x, int y);        [DllImport("CSharpInvokeCPP.CPPDemo.dll")]        public static extern int Multiply(int x, int y);        [DllImport("CSharpInvokeCPP.CPPDemo.dll")]        public static extern int Divide(int x, int y);        [DllImport("CSharpInvokeCPP.CPPDemo.dll")]        public static extern int Sum(int[] Parr , int length);        [DllImport("CSharpInvokeCPP.CPPDemo.dll")]        public static extern IntPtr Create(string name, int age);        [StructLayout(LayoutKind.Sequential)]        public struct User        {            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]            public string Name;            public int Age;        }           }

6 把CSInvokeCDll.dll复制到CSInvokeCPP下的/bin/Debug目录下

7 main函数调用:

static void Main(string[] args)        {            int result = CPPAdapter.Add(10, 20);            int[] arr = new int[] { 1, 2, 3, 4, 5 };            Console.WriteLine("10 + 20 = {0}", result);            result = CPPAdapter.Sub(30, 12);            Console.WriteLine("30 - 12 = {0}", result);            result = CPPAdapter.Multiply(5, 4);            Console.WriteLine("5 * 4 = {0}", result);            result = CPPAdapter.Divide(30, 5);            Console.WriteLine("30 / 5 = {0}", result);                result = CPPAdapter.Sum(arr, 5);            Console.WriteLine("sum is {0}", result);                       IntPtr ptr = CPPAdapter.Create("Chevkio", 27);            CPPAdapter.User user = (CPPAdapter.User)Marshal.PtrToStructure(ptr, typeof(CPPAdapter.User));            Console.WriteLine("Name: {0}, Age: {1}", user.Name, user.Age);            Console.ReadLine();        }

调用结果:

总结:

本文实现了C#通过DllImport和Marshal类对C Dll文件的引用对于native C++, CLI/C++ 及 C#的效率问题会在下面文章中提到.

疑问:

在C函数Create中申请了内存空间

User* user = (User*)malloc(sizeof(User));

,不知道在哪里释放比较合适. 请高手指点.