Csharp 创建在C++可执行文件中使用的C#DLL

我已经在这个话题上挣扎了一周，但我try 的任何东西似乎都没有奏效. 我创建了一个非常简单的C#类:

namespace SimpleMathLib
{
    public class SimpleMath
    {
        public float SumFloat(float a, float b)
        {
            return a + b;
        }

        public int SumInt(int a, int b)
        {
            return a + b;
        }
    }
}

in a Visual Studio 2022 solution configured to build a DLL:

我确实阅读了一些在线教程，但给我带来的问题较少的是关于创建使用CLR的C++包装器并将其编译为静态库(.lib)的教程. 下面是我在这个包装器中添加的脚本:

// SimpleMathLibWrapper.h
#pragma once

class SimpleMathLibWrapperPrivate;

class __declspec(dllexport) SimpleMathLibWrapper
{
    private:
        SimpleMathLibWrapperPrivate* _private;

    public:
        SimpleMathLibWrapper();
        ~SimpleMathLibWrapper();

        float SumFloat(const float a, const float b);
        int SumInt(const int a, const int b);
};

// SimpleMathLibWrapper.cpp
#include "..\public\SimpleMathLibWrapper.h"

#include <msclr\auto_gcroot.h>
#include <msclr\marshal_cppstd.h>

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

class SimpleMathLibWrapperPrivate
{
    public:
        msclr::auto_gcroot<SimpleMath^> simpleMathCSharp;
};

SimpleMathLibWrapper::SimpleMathLibWrapper()
{
    _private = new SimpleMathLibWrapperPrivate();
    _private->simpleMathCSharp = gcnew SimpleMath();
}

SimpleMathLibWrapper::~SimpleMathLibWrapper()
{
    delete _private;
}

float SimpleMathLibWrapper::SumFloat(const float a, const float b)
{
    return _private->simpleMathCSharp->SumFloat(a, b);
}

int SimpleMathLibWrapper::SumInt(const int a, const int b)
{
    return _private->simpleMathCSharp->SumInt(a, b);
}

and these are the settings of the Visual Studio CLR library project I had to change: moreover, I added the compiled C# DLL reference to the project

现在，对于C++可执行项目，它是一个带有以下脚本的Visual Studio C++控制台项目:

// SimpleMathLibUser.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

//#define LOAD_DLL_MANUALLY

#include <iostream>
#include <Windows.h>

#ifndef LOAD_DLL_MANUALLY
    #include "SimpleMathLibWrapper.h"
#endif // !LOAD_DLL_MANUALLY


#ifdef LOAD_DLL_MANUALLY
    void PrintExecutablePath()
    {
        TCHAR exePath[MAX_PATH];
        GetModuleFileName(NULL, exePath, MAX_PATH);
        char narrowExePath[MAX_PATH];

        // convert the string to a narrow character string
        if (WideCharToMultiByte(CP_ACP, 0, exePath, -1, narrowExePath, MAX_PATH, 0, 0) == 0)
        {
            std::cerr << "Failed to convert the path to a narrow character string." << std::endl;
            return;
        }

        char* lastSlash = strrchr(narrowExePath, '\\');
        if (lastSlash != NULL)
        {
            *lastSlash = '\0';
        }

        std::cout << "Current directory: " << narrowExePath << std::endl << std::endl;
    }
#endif // LOAD_DLL_MANUALLY

int main()
{
#ifdef LOAD_DLL_MANUALLY
    PrintExecutablePath();

    // load the DLL.
    HMODULE mathLib = LoadLibrary(TEXT("..\\Plugins\\SimpleMathLibWrapper.dll"));

    if (mathLib == NULL)
    {
        std::cerr << "Failed to load the DLL." << std::endl;
        return 1;
    }

    // get a pointer to functions from the DLL.
    float (*SumFloat)(float, float) = (float (*)(const float, const float))GetProcAddress(mathLib, "SumFloat");
    int (*SumInt)(int, int) = (int (*)(const int, const int))GetProcAddress(mathLib, "SumInt");

    if (SumFloat == NULL)
    {
        std::cerr << "Failed to find the 'SumFloat' function in the DLL." << std::endl;
        return 1;
    }

    if (SumInt == NULL)
    {
        std::cerr << "Failed to find the 'SumInt' function in the DLL." << std::endl;
        return 1;
    }

    // call the functions.
    float resultFloat = SumFloat(10.f, 5.f);
    std::cout << "Float Sum: " << resultFloat << std::endl;

    int resultInt = SumInt(2, 3);
    std::cout << "Int Sum: " << resultInt << std::endl;

    // unload the DLL.
    FreeLibrary(mathLib);
#else
    SimpleMathLibWrapper wrapper;

    std::cout << "Float Sum: " << wrapper.SumFloat(10.f, 5.f) << std::endl;
    std::cout << "Int Sum: " << wrapper.SumInt(2, 3) << std::endl;
#endif // LOAD_DLL_MANUALLY

    return 0;
}

如你所见，为此，我try 了两种方法:

1. 手动加载包装器
2. 使用链接器

These are the settings I added for the linker solution (which is currently the one that at least compile and seems to work until a certain point):

C#DLL是用哪个.NET版本编译的并不重要，当我运行可执行文件时，我总是得到以下错误:

Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'netstandard, Version=2.1.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. Impossible to find the scpecified file.
   in SimpleMathLibWrapper.{ctor}(SimpleMathLibWrapper* )
   in mainCRTStartup()

我所知道的是.NET版本的Runtime和SDK都已安装并在系统中正确引用. 无论我在C#VS项目中 Select 目标框架的哪个版本，结果都是相同的；只是程序集名称和版本发生了变化.

我也在互联网上寻找这个特定的问题，但大多数解决方案都是try 直接从.sln文件而不是从VS打开项目，这对我不起作用.

手动加载DLL会导致一系列我无法解决的不同问题，因此，我保留了代码以供参考，但放弃了try 修复它.

我知道这是一篇很长的帖子，我鼓励你问我更多的细节，以防我遗漏了什么. 希望在这里找到解决方案将能够在future 帮助更多的人.

谢谢！！