C ++在运行时更改HWND窗口过程 [英] C++ Changing HWND Window Procedure in runtime

问题描述

我正在一个IDE中创建一个hwnd及其相应的WndProc LRESULT CALLBACK.我需要将WndProc更改为自定义名称.

I'm working in an IDE which creates a hwnd and its respective WndProc LRESULT CALLBACK. I need to change the WndProc to a custom one.

我已经阅读到SetWindowLong可以完成工作，但是我找不到任何有效的示例.例如:

I've read that SetWindowLong would do the job but I can't find any working example. For example:

HWND hwnd; //My window

SetWindowLong(hwnd, GWL_WNDPROC, myNewWndProc);

SetWindowLong的第三参数是Long，因为函数名称为其命名.如何从我的WndProc函数引用到Long?

Third parameter for SetWindowLong is a Long as the name of the function names it. How can I make a reference from my WndProc function to a Long?

我的WndProc:

LRESULT CALLBACK WndProcedure(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam){

msg_dev(toString(uMsg));

switch(uMsg){

    case WM_MOUSEMOVE:
        SetCursor(LoadCursor(NULL, IDC_HAND));
        break;

    case WM_LBUTTONDOWN:
        msg_dev("Button down!");
        break;

    default:
        DefWindowProc(hwnd, uMsg, wParam, lParam);
}

return 0;
};

推荐答案

您需要使用以下内容:

WNDPROC prevWndProc;
...
prevWndProc = (WNDPROC) SetWindowLongPtr(hwnd, GWL_WNDPROC, (LONG_PTR)&myNewWndProc);
...    
LRESULT CALLBACK myNewWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    msg_dev(toString(uMsg));

    switch(uMsg)
    {
        case WM_MOUSEMOVE:
            SetCursor(LoadCursor(NULL, IDC_HAND));
            break;

        case WM_LBUTTONDOWN:
            msg_dev("Button down!");
            break;
    }

    return CallWindowProc(prevWndProc, hwnd, uMsg, wParam, lParam);
}

查看本文:

子类化窗口时，它是子类化窗口的原始窗口过程要调用原始窗口过程时调用

话虽如此，您应该使用 SetWindowSubclass() 而不是SetWindowLongPtr().看到这篇文章:

That being said, you should use SetWindowSubclass() instead of SetWindowLongPtr(). See this article:

更安全的子类

例如:

SetWindowSubclass(hwnd, &mySubClassProc, 1, 0);
...    
LRESULT CALLBACK mySubClassProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
    msg_dev(toString(uMsg));

    switch(uMsg)
    {
        case WM_MOUSEMOVE:
            SetCursor(LoadCursor(NULL, IDC_HAND));
            break;

        case WM_LBUTTONDOWN:
            msg_dev("Button down!");
            break;

        case WM_NCDESTROY:
            RemoveWindowSubclass(hWnd, &mySubClassProc, 1);
            break;
    }

    return DefSubclassProc(hWnd, uMsg, wParam, lParam);
}

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