Question

下面是我的c ++ DLL

// DLL.cpp : Defines the exported functions for the DLL application.
#include "stdafx.h"
//#include <stdexcept> 
#include<iostream>
using namespace std; 

typedef void (*FunctionPtr)(int); 
void (*FunctionPtr1)(int); 
extern "C" __declspec(dllexport)void Caller();
extern "C" __declspec(dllexport)void RegisterFunction(FunctionPtr func_ptr); 


    extern void Caller() 
    {    

        int i = 10;
        FunctionPtr1(i);
 } 

    extern void RegisterFunction(FunctionPtr func_ptr1)
 {
     FunctionPtr1 = func_ptr1;

 }

此DLL将从c＃引用函数名称并将参数传递给c＃函数。这是我的c＃代码

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



namespace test
{
    class Program
    {

        [DllImport("C:/Users/10602857/Documents/Visual Studio 2010/Projects/DLL/Debug/DLL.dll", CallingConvention = CallingConvention.Cdecl)]
        public static extern void Caller();

       [DllImport("C:/Users/10602857/Documents/Visual Studio 2010/Projects/DLL/Debug/DLL.dll", CallingConvention = CallingConvention.Cdecl)]
        public static extern fPointer  RegisterFunction(fPointer aa);

        static void Main(string[] args)
            {
                    Console.WriteLine("DLL Linking");
                    fPointer abc = new fPointer(ping);
                    RegisterFunction(abc);      //send address of function to DLL
                    Caller();                   //call from DLL
            }

        public  delegate void fPointer(int s);       // point to every functions that it has void as return value and with no input parameter 


        public static void ping(int a)
             {
                     Console.WriteLine("ping executed " + a);
             }

        public static void add1()
              {
                      Console.WriteLine("add executed");
              }

    }
}

c＃代码能够获得我在c ++ dll中使用的值，如下所示

int i = 10;
        FunctionPtr1(i);

M得到了sedired输出，但是progrram在最后被执行了以下操作

Unhandled Exception: System.AccessViolationException: Attempted to read or write
 protected memory. This is often an indication that other memory is corrupt.
   at test.Program.Caller()

为什么我得到这个？

Answer 1

好的，我为你编写了测试代码。概念很简单。

您使用C ++或C编写了dll。
CLR库（托管dll）包装你的dll。
您的C＃代码可以通过CLR库使用您的本机DLL。

您的原生DLL

<强> MyDll.cpp

#include "stdafx.h"

#include<iostream>
using namespace std; 

typedef void (*FunctionPtr)(int); 
void (*FunctionPtr1)(int); 
extern "C" __declspec(dllexport)void Caller();
extern "C" __declspec(dllexport)void RegisterFunction(FunctionPtr func_ptr); 


extern void Caller() 
{    
    int i = 10;
    FunctionPtr1(i);
} 

extern void RegisterFunction(FunctionPtr func_ptr1)
{
    FunctionPtr1 = func_ptr1;
}

您的CLR库，Native Dll的包装器

<强> MyDllCLR.h

#pragma once

using namespace System;
using namespace System::Runtime::InteropServices;

typedef void (*FunctionPtr2)(int); 
extern "C" __declspec(dllimport)void Caller();
extern "C" __declspec(dllimport)void RegisterFunction(FunctionPtr2 func_ptr); 

namespace MyDllCLR {

    void MyFunc(int i);

    public ref class Class
    {        
    public:
        delegate void FunctionDelegate(int i);
        static FunctionDelegate^ fun;

        static void Caller1()
        {
            Caller();
        }

        static void RegisterFunction1(FunctionDelegate^ f)
        {
            fun = f; // Wrapper MyFunc call this delegate

            // this occurs runtime error and I don't know why.
            // So I wrote Warpper MyFunc() method. I usually do like this.
            //IntPtr p = Marshal::GetFunctionPointerForDelegate(fun);
            //RegisterFunction((FunctionPtr2)(void*)p);

            // Register Function Wrapper instead of user delegate.
            RegisterFunction(MyFunc);
        }
    };    
}

<强> MyDllCLR.cpp

#include "stdafx.h"
#include "MyDllCLR.h"

void MyDllCLR::MyFunc(int i)
{
    MyDllCLR::Class::fun(i);
}

使用Native DLL的C＃代码

<强> Program.cs的

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TestMyDllCLR
{
    class Program
    {
        static void MyFunc(int i)
        {
            Console.WriteLine("Come on! {0}", i);
        }

        static void Main(string[] args)
        {
            MyDllCLR.Class.RegisterFunction1(MyFunc);
            MyDllCLR.Class.Caller1();
        }
    }
}

对于Program.cs，您需要Native DLL和CLR DLL

当然，这不是实现目标的唯一途径。：）

Answer 2

很可能是你的代表

fPointer abc = new fPointer(ping);

在使用之前收集垃圾。您需要将对委托的引用存储为类的字段，以确保它在类的生命周期中存活。

尝试在fPointer abc之外定义main，然后在new fPointer(ping)内为main分配{{1}}，看看是否有帮助。

Answer 3

我需要做的就是...... 只是声明我的代表是......

[UnmanagedFunctionPointer(CallingConvention.Cdecl)] 
public delegate void MyDelegate();

未处理的异常：System.AccessViolationException：尝试读取或写入

3 个答案: