Question

所以我练习在Win32中继承预定义的窗口类，这样我就可以为预定义的类定义自己的自定义消息proc（例如为按钮类创建一个自定义的WndProc），我让它最适合工作部分但我无法将WM_COMMAND消息自动发送到新消息proc。我可以在WM_COMMAND的父窗口中设置一个案例，然后检查wParam，然后为发送WM_COMMAND消息的子窗口调用相应的新消息proc，但我希望像所有其他命令一样自动完成。至于我可以告诉所有其他WM我在自定义消息proc中尝试过，我从父窗口的消息proc中自动传递给它，但WM_COMMAND消息不会被取消，除非我明确地重定向它们。我有一种感觉WM_COMMAND消息将永远发送到父窗口，当我按照它设置的方式进行子类化时，但是如果有人可以解释为什么会出现这种情况或我需要做什么来指导所有属于按钮窗口到我定义的自定义WndProc，非常感谢。

代码：

#include <Windows.h>
#include <windowsx.h>

#define IDC_BUTTON   0


LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
LRESULT CALLBACK WndProcButton (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);

HWND    g_hwndButton            = NULL;
WNDPROC g_wndProcButtonOrigianl = NULL;
BOOL    g_bSeeingMouse          = FALSE;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    LPSTR szCmdLine, int iCmdShow)
{
     static TCHAR szClassName[] = TEXT ("HelloWin") ;
     HWND         hwnd ;
     MSG          msg ;
     WNDCLASS     wndclass ;

     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
     wndclass.lpfnWndProc   = WndProc ;
     wndclass.cbClsExtra    = 0 ;
     wndclass.cbWndExtra    = 0 ;
     wndclass.hInstance     = hInstance ;
     wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
     wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
     wndclass.lpszMenuName  = NULL ;
     wndclass.lpszClassName = szClassName ;

     if (!RegisterClass (&wndclass))
     {
          MessageBox (NULL, TEXT ("This program requires Windows NT!"), 
                      szClassName, MB_ICONERROR) ;
          return 0 ;
     }

     hwnd = CreateWindow (szClassName,                // window class name
                          TEXT ("The Hello Program"), // window caption
                          WS_OVERLAPPEDWINDOW,        // window style
                          CW_USEDEFAULT,              // initial x position
                          CW_USEDEFAULT,              // initial y position
                          CW_USEDEFAULT,              // initial x size
                          CW_USEDEFAULT,              // initial y size
                          NULL,                       // parent window handle
                          NULL,                       // window menu handle
                          hInstance,                  // program instance handle
                          NULL) ;                     // creation parameters

     ShowWindow (hwnd, iCmdShow) ;
     UpdateWindow (hwnd) ;

     while (GetMessage (&msg, NULL, 0, 0))
     {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
     }
     return msg.wParam ;
}


LRESULT CALLBACK WndProcButton (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch( message )
    {
    case WM_COMMAND:
        MessageBox( hwnd, TEXT( "Test box" ), TEXT( "Test box" ), MB_OK );
        SetFocus( g_hwndButton );
        break;
    default:
        if( !g_bSeeingMouse && GetCapture() == hwnd )
        {
            g_bSeeingMouse = TRUE;
            SetWindowText( hwnd, L"Ok +mouse" );
        }
        else if( g_bSeeingMouse && GetCapture() != hwnd )
        {
            g_bSeeingMouse = FALSE;
            SetWindowText( hwnd, L"Ok" );
        }
        break;
    }
    return CallWindowProc( g_wndProcButtonOrigianl, hwnd, message, wParam, lParam );
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     HDC         hdc ;
     PAINTSTRUCT ps ;
     RECT        rect ;

     switch (message)
     {
     case WM_CREATE:
         g_hwndButton = CreateWindow( L"Button",                                            // predefined class
                                      L"Ok",                                                // button text
                                      ( WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON ),         // styles
                                      // Size and poition values are given explicitly, because
                                      // the CW_USEDEFAULT constant gives zero values for buttons.
                                      10,                                                   // starting x position
                                      10,                                                   // starting y position
                                      100,                                                  // button width
                                      30,                                                   // button height
                                      hwnd,                                                 // parent window
                                      (HMENU)IDC_BUTTON,                                    // no menu
                                      (HINSTANCE)GetWindowLongPtr( hwnd, GWLP_HINSTANCE ),
                                      NULL );                                               // pointer not needed
         SetFocus( g_hwndButton );
         g_wndProcButtonOrigianl = (WNDPROC)SetWindowLongPtr( g_hwndButton, GWLP_WNDPROC, (LONG_PTR)WndProcButton );
          return 0 ;

     case WM_PAINT:
          hdc = BeginPaint (hwnd, &ps) ;

          GetClientRect (hwnd, &rect) ;

          DrawText (hdc, TEXT ("Hello, Windows 98!"), -1, &rect,
                    DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;

          EndPaint (hwnd, &ps) ;
          return 0 ;

     case WM_DESTROY:
          PostQuitMessage (0) ;
          return 0 ;
     }
     return DefWindowProc (hwnd, message, wParam, lParam) ;
}

Answer 1

按照设计，WM_COMMAND和WM_NOTIFY消息将发送到控件的父窗口。无法使API自动将它们发送到生成它们的控件。父窗口必须根据需要处理它们或转发它们。没有避免这种情况。

在最初由Borland编写并现在由Embarcadero拥有的VCL框架中，它使用一个简单的系统来转发此类消息。当任何父窗口收到这些消息之一时，它会将消息ID递增一个偏移量，该消息将消息放入用户定义的范围，然后将消息转发给消息中指定的子HWND。因此，WM_COMMAND变为CN_COMMAND，WM_NOTIFY变为CN_NOTIFY，这是子控件的窗口过程可以查找的内容。

例如：

#define MY_COMMAND  (WM_COMMAND + some_offset)
#define MY_NOTIFY   (WM_NOTIFY + some_offset)

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     switch (message)
     {
     case WM_COMMAND:
         if (lParam != 0)
             SendMessage((HWND)lParam, MY_COMMAND, wParam, lParam);
         return 0;

     case WM_NOTIFY:
         SendMessage(((NMHDR*)lParam)->hwndFrom, MY_NOTIFY, wParam, lParam);
         return 0;

     ...
     }

     return DefWindowProc (hwnd, message, wParam, lParam) ;
}

LRESULT CALLBACK WndProcButton (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch( message )
    {
    case MY_COMMAND:
        ...
    case MY_NOTIFY:
        ...
    }

    return CallWindowProc( g_wndProcButtonOrigianl, hwnd, message, wParam, lParam );
}

Win32子类 - 关于消息

1 个答案: