c++ - WIN32，两个窗口使用相同的 wndproc...为什么？

Question

我正在尝试创建两个使用两个不同 wndproc 的窗口。 我创建了两个单独的 wndproc 和两个单独的窗口类，它们指向它们自己的 wndproc 回调。

但出于某种原因，两个窗口都使用相同的 wndproc.... 我的第二个窗口在技术上应该使用 WndProcControl，但是它使用 WndProc 就像我的第一个窗口是...

为什么要这样做？这是我的代码:

// Edit.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "TaylorSoundEditor.h"

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;                                // current instance
TCHAR szTitle[MAX_LOADSTRING];                  // The title bar text
TCHAR szControl[MAX_LOADSTRING]; //The title bar for the Control window
TCHAR szWindowClass[MAX_LOADSTRING];            // the main window class name
TCHAR szControlClass[MAX_LOADSTRING]; //the control window class name

// Forward declarations of functions included in this code module:
ATOM                MyRegisterClass(HINSTANCE hInstance);
ATOM                MyRegisterControlClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK    WndProcControl(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY _tWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPTSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // TODO: Place code here.
    MSG msg;
    HACCEL hAccelTable;

    // Initialize global strings
    LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadString(hInstance, IDS_CONTROL_TITLE, szControl, MAX_LOADSTRING);
    LoadString(hInstance, IDC_TAYLORSOUNDEDITOR, szWindowClass, MAX_LOADSTRING);
    LoadString(hInstance, IDC_TAYLORSOUNDEDITOR, szControlClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);
    MyRegisterControlClass(hInstance);

    // Perform application initialization:
    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

    hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_TAYLORSOUNDEDITOR));

    // Main message loop:
    while (GetMessage(&msg, NULL, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}



//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_TAYLORSOUNDEDITOR));
    wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = MAKEINTRESOURCE(IDC_TAYLORSOUNDEDITOR);
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassEx(&wcex);
}

ATOM MyRegisterControlClass(HINSTANCE hInstance)
{
    WNDCLASSEX controlex;

    controlex.cbSize = sizeof(WNDCLASSEX);

    controlex.style         = CS_HREDRAW | CS_VREDRAW;
    controlex.lpfnWndProc   = WndProcControl;
    controlex.cbClsExtra        = 0;
    controlex.cbWndExtra        = 0;
    controlex.hInstance     = hInstance;
    controlex.hIcon         = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_TAYLORSOUNDEDITOR));
    controlex.hCursor       = LoadCursor(NULL, IDC_ARROW);
    controlex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    controlex.lpszMenuName  = MAKEINTRESOURCE(IDC_TAYLORSOUNDEDITOR);
    controlex.lpszClassName = szControlClass;
    controlex.hIconSm       = LoadIcon(controlex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassEx(&controlex);
}

//
//   FUNCTION: InitInstance(HINSTANCE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd, controlWnd;

   hInst = hInstance; // Store instance handle in our global variable

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   controlWnd = CreateWindow(szControlClass, szControl, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);
   ShowWindow(controlWnd, nCmdShow);
   UpdateWindow(controlWnd);
   return TRUE;
}

//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_COMMAND  - process the application menu
//  WM_PAINT    - Paint the main window
//  WM_DESTROY  - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;

    switch (message)
    {
    case WM_CREATE:
        MessageBox(hWnd, L"TEXT", L"TESTTT", 0);
        break;
    case WM_COMMAND:
        wmId    = LOWORD(wParam);
        wmEvent = HIWORD(wParam);
        // Parse the menu selections:
        switch (wmId)
        {
        case IDM_ABOUT:
            DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
            break;
        case IDM_EXIT:
            DestroyWindow(hWnd);
            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
        break;
    case WM_PAINT:
        hdc = BeginPaint(hWnd, &ps);
        // TODO: Add any drawing code here...
        EndPaint(hWnd, &ps);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

LRESULT CALLBACK WndProcControl(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;

    switch (message)
    {
    case WM_CREATE:
        MessageBox(hWnd, L"TEXT2", L"TESTTT2", 0);
        CreateWindow(TEXT("button"), TEXT("hello"), WS_VISIBLE | WS_CHILD, 0, 0, 200, 85, hWnd, (HMENU) 1, NULL, NULL);
        break;
    case WM_COMMAND:
        wmId    = LOWORD(wParam);
        wmEvent = HIWORD(wParam);
    case WM_PAINT:
        hdc = BeginPaint(hWnd, &ps);
        // TODO: Add any drawing code here...
        EndPaint(hWnd, &ps);
        break;
    case WM_DESTROY:
        //PostQuitMessage(0);
        break;
    }
    return DefWindowProc(hWnd, message, wParam, lParam);
}

// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}

Answer 1

您尝试注册两个窗口类。但是你给了他们两个相同的类名。所以第二次尝试失败了。然后创建两个窗口，将相同的窗口类名称传递给对 CreateWindow 的两次调用。

查看您对 LoadString 的调用。

LoadString(hInstance, IDC_TAYLORSOUNDEDITOR, szWindowClass, MAX_LOADSTRING);
LoadString(hInstance, IDC_TAYLORSOUNDEDITOR, szControlClass, MAX_LOADSTRING);

很明显，这样做的结果是 szWindowClass 和 szControlClass 具有相同的值。

如果您没有忽略调用 RegisterClassEx 的返回值，您自己就会发现这一点。由于显而易见的原因，第二次调用失败了。不要忽略返回值!