从 .NET 调用本机 Win32 代码(C++/CLI 和 C#) [英] Calling native Win32 code from .NET (C++/CLI and C#)

问题描述

我正在为 C# 开发一个应用程序，我想使用 DirectX(主要是 Direct2D)作为它的图形组件.所以我尝试使用 C++/CLI 作为原生 C++ 代码和 C# 托管代码之间的中间层.到目前为止，我的解决方案中有 3 个项目:AC# 项目(我不会真正讨论它，因为它还没有给我任何问题)，一个包含 Windows.h 的 C++ 静态库，以及一个用于在其他两个项目之间编组信息的动态 C++/CLI 库.到目前为止，这是我的代码:

I'm developing an app for C#, and I want to use DirectX (mostly Direct2D) for the graphical component of it. So I'm trying use use C++/CLI as an intermediary layer between the native C++ code and the managed code of C#. So far a have 3 projects in my solution: A C# project (which I won't really discuss since it's not giving me any problems yet), a C++ static library that includes Windows.h, and a dynamic C++/CLI library that's intended to marshal information between the other two projects. Here is my code so far:

在本机 C++ 项目中，我有一个名为 RenderWindowImpl 的类，因此它只包含 2 个方法:

In the native C++ project, I have a class named RenderWindowImpl that so for only contains 2 methods:

//RenderWindowImpl.h
#pragma once

#include <Windows.h>

class RenderWindowImpl final
{
public:
    RenderWindowImpl() = default;
    ~RenderWindowImpl() = default;

    int test();

private:
    static void InitializeWin32Class();
};

<小时>

// RenderWindowImpl.cpp
#include "RenderWindowImpl.h"

int RenderWindowImpl::test()
{
    return 5;
}

void RenderWindowImpl::InitializeWin32Class()
{
    WNDCLASSEXW wc = { 0 };

    wc.cbSize = sizeof(WNDCLASSEXW);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = nullptr;
    wc.hInstance = GetModuleHandleW(0);
    wc.hCursor = LoadCursorW(nullptr, IDC_ARROW);
    //wc.lpszClassName = L"wz.1RenderWindowImpl";

    //// TODO: error check
    //RegisterClassExW(&wc);
}

在我的 C++/CLI 项目中，我有一个名为 RenderWindow 的类，它充当 RenderWindowImpl 的包装器:

And in my C++/CLI project, I have a class named RenderWindow that acts as a wrapper around RenderWindowImpl:

// wzRenderWindow.h
#pragma once

//#pragma managed(push, off)
#include "RenderWindowImpl.h"
//#pragma managed(pop)

using namespace System;

namespace wzRenderWindow {

    public ref class RenderWindow sealed
    {
    public:
        RenderWindow();
        ~RenderWindow();

        int test();

    private:
        RenderWindowImpl* impl;
    };
}

<小时>

// wzRenderWindow.h.
#include "stdafx.h"
#include "wzRenderWindow.h"

wzRenderWindow::RenderWindow::RenderWindow()
{
    // Initialize unmanaged resource
    impl = new RenderWindowImpl();

    try
    {
        // Any factory logic can go here
    }

    catch (...)
    {
        // Catch any exception and avoid memory leak
        delete impl;
        throw;
    }
}

wzRenderWindow::RenderWindow::~RenderWindow()
{
    // Delete unmanaged resource
    delete impl;
}

int wzRenderWindow::RenderWindow::test()
{
    return impl->test();
}

当我编译我的项目时，我收到以下警告和错误:

When I compile my project, I get the following warnings and errors:

1. Error LNK1120 1 unresolved externals wzRenderWindow d:\documents\visual studio 2015\Projects\WizEngCS\Debug\wzRenderWindow.dll 1
2. 警告 LNK4075 由于/OPT:LBR"规范而忽略/EDITANDCONTINUE" wzRenderWindow d:\documents\visual studio 2015\Projects\WizEngCS\wzRenderWindow\wzRenderWindowImpl.lib(RenderWindowImpl.obj) 1
3. 函数private: static void __cdecl RenderWindowImpl::InitializeWin32Class(void)" (?InitializeWin32Class@RenderWindowImpl@@CAXXZ) wzRenderWindow d:\documents\visualCSProjects\Wiziz 中引用的错误 LNK2019 未解析的外部符号 __imp__LoadCursorW@8\wzRenderWindow\wzRenderWindowImpl.lib(RenderWindowImpl.obj) 1

这似乎是 C++/CLI 不喜欢对 LoadCursorW 的调用，因为如果我注释掉该行，代码编译得很好.删除 Win32 函数调用后，我能够从 C# 应用程序成功调用 RenderWindow::test()，输出预期结果 5.

It seems to be the call to LoadCursorW that C++/CLI doesn't like, as the code compiles fine if I comment out that line. With the Win32 function calls removed, I was able to successfully call RenderWindow::test() from a C# application, outputting the expected result of 5.

我有点不知所措，因为我对 C++/CLI 的理解是，它非常擅长包装本地 C++ 类以供托管 .NET 应用程序使用.我真的很想了解为什么我的代码没有编译.

I'm a bit of a loss because my understanding of C++/CLI is that it's very good at wrapping native C++ classes for consumption by managed .NET applications. I would really like to understand why my code is not compiling.

作为一个相关的后续问题，我在这里吠错树了吗?从 .NET 访问 DirectX 方法(或类似的基于 COM 的 C/C++ 库)的传统方式是什么?我想避免使用 SharpDX 等第三方包装库.

As a related follow-up question, am I barking up the wrong tree here? What's the conventional way to access DirectX methods (or similar COM-based C/C++ libraries) from .NET? I'd like to avoid using 3rd-party wrapper libraries like SharpDX.

推荐答案

我通过将 #pragma comment(lib, "User32.lib") 放在我的 RenderWindowImpl.cpp.感谢@andlabs 的修复.我不知道为什么这解决了这个问题(我以前的任何项目都不需要显式链接到 user32.lib).

I fixed the problem by putting #pragma comment(lib, "User32.lib") at the top of my RenderWindowImpl.cpp. Thanks to @andlabs for the fix. I'm not sure why this fixed the problem (I've never needed to explicitly link to user32.lib in any of my previous projects).

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