明确声明时显示“DialogProc 未声明”错误

Question

我正在构建我的第一个 GUI。

以下是我的代码。

#include <windows.h>
#include "resource.h"

const char g_szClassName[] = "home";

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch(msg)
    {
        case WM_CLOSE:
            DestroyWindow(hwnd);
            break;
        case WM_DESTROY:
            PostQuitMessage(0);
            break;
        default:
            return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

BOOL CALLBACK HomeDialogProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch (msg) {
        case WM_COMMAND:
            switch(LOWORD(wParam)){
                case IDC_ABOUT:
                    CreateDialog(GetModuleHandle(NULL), MAKEINTRESOURCE(IDT_ABOUTDIALOG), hwnd, AboutDlgProc);
                    break;
            }
            break;
        default:
            return FALSE;
    }
    return FALSE;
}

BOOL CALLBACK AboutDlgProc(HWND hwnd, UINT Msg, WPARAM wParam, LPARAM lParam) {
    switch(Msg)
    {
        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
                case IDC_DLG_EXIT:
                    DestroyWindow(hwnd);
                    break;
            }
            break;
        default:
            return FALSE;
    }
    return FALSE;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
    WNDCLASSEX wc;
    HWND hwnd;
    HWND dialog;
    MSG Msg;

    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = 0;
    wc.lpfnWndProc = WndProc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hInstance = hInstance;
    wc.hIcon = LoadIcon(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON));
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);
    wc.lpszMenuName = MAKEINTRESOURCE(IDR_MYMENU);
    wc.lpszClassName = g_szClassName;
    wc.hIconSm = (HICON) LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON), IMAGE_ICON, 16, 16, 0);

    if (!RegisterClassEx(&wc)) {
        MessageBox(NULL, "Window Registration Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    hwnd = CreateWindowEx(
            WS_EX_CLIENTEDGE,
            g_szClassName,
            "Have faith, we will succeed",
            WS_OVERLAPPEDWINDOW,
            CW_USEDEFAULT, CW_USEDEFAULT, 800, 500,
            NULL, NULL, hInstance, NULL);

    if (hwnd == NULL) {
        MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    dialog = CreateDialog(hInstance, MAKEINTRESOURCE(IDT_HOMEDIALOG), hwnd, HomeDialogProc);

    if (!dialog) {
        MessageBox(NULL, "Could not create Dialog", "CreateDialog", MB_ICONERROR);
        return 1;
    }

    ShowWindow(dialog, nCmdShow);
    UpdateWindow(dialog);

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

我想简单介绍一下我想做的事情。我在主窗口中嵌入了一个对话框，因此它“成为窗口的一部分”。然后在这个对话框中有一个关于按钮应该打开关于对话框。我对编译错误感到非常沮丧：

C:\Workspace_cpp\twodlg\main.cpp:28:97: error: 'AboutDlgProc' was not declared in this scope
                 CreateDialog(GetModuleHandle(NULL), MAKEINTRESOURCE(IDT_ABOUTDIALOG), hwnd, AboutDlgProc);

如你所见，我已经明确定义了AboutDlgProc。另一方面，根据我的阅读，所有DialogProc 函数不一定需要声明才能起作用。最后，即使在我明确地放入声明语句之后，错误仍然存​​在。非常感谢您的帮助。

Answer 1

当我将AboutDlgProc 向上移动时，我解决了这个问题。 @MikeNakis 在评论中提供了答案，我刚刚结束了这个问题。