如何使用 SetTimer() 在 C++ 中创建一定数量的消息框？

Question

我正在努力做到这一点，当一个消息框打开时，另一个消息框会在几秒钟后打开，而无需任何用户输入（按 OK 按钮）。我希望旧的保持打开状态，但出现新的。我还希望能够使用 SetWindowsHookEx 并限制创建的消息框数量。我知道这使用函数 SetTimer() 并且需要某种 if 语句，其中当前的对话框数量等于限制并在达到该数量时停止。那么我该如何进行这项工作呢？我试图研究，但似乎没有任何效果。

我的尝试：

#include <iostream>
#include <Windows.h>
#include <string>
using namespace std;

thread_local int MsgBox_X;
thread_local int MsgBox_Y;
thread_local int Limit = 10;

static LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam)
{
    if (nCode == HCBT_CREATEWND)
    {
        CBT_CREATEWND* s = (CBT_CREATEWND*)lParam;
        if (s->lpcs->hwndParent == NULL)
        {
            s->lpcs->x = MsgBox_X;
            s->lpcs->y = MsgBox_Y;
        }
    }
    return CallNextHookEx(NULL, nCode, wParam, lParam);
}

int MessageBoxPos(HWND hWnd, LPCTSTR lpText, LPCTSTR lpCaption, UINT uType, int X, int Y)
{
    HHOOK hHook = SetWindowsHookEx(WH_CBT, &CBTProc, NULL, GetCurrentThreadId());
    MsgBox_X = X;
    MsgBox_Y = Y;
    int result = MessageBox(hWnd, lpText, lpCaption, uType);
    if (hHook) UnhookWindowsHookEx(hHook);
    return result;
if (<# of dialogs> == Limit) {
    std::terminate()
    }
}

void _MessageBox()
{
    HWND HWND1;
    MessageBox(HWND1, TEXT("Message"), TEXT("MsgBox"), MB_ICONWARNING | MB_OK);
    SetTimer(HWND1, 
        TIMER1,
        2000,
        (TIMERPROC)NULL);
    case WM_TIMER:

        switch (wParam)
        {
        case TIMER1:
            MessageBoxPos(NULL, TEXT("Message 2"), TEXT("MsgBox 2"), MB_ICONWARNING | MB_OK, 50, 50);

            return 0;
        }
    }
}
int main()
{
    ShowWindow(::GetConsoleWindow(), SW_HIDE);
    _MessageBox();
}

Answer 1

您正在将 未初始化的 HWND 传递给 MessageBox()。

此外，MessageBox()是一个阻塞函数，直到对话框关闭它才会退出，所以你需要在调用之前创建定时器MessageBox()。除非您使用 SetWindowsHookEx() 或 SetWinEventHook() 挂钩对话框的创建，否则您可以在创建对话框的 HWND 时创建计时器，然后将 HWND 传递给 SetTimer().

此外，您处理 WM_TIMER 消息的语法完全错误。

也就是说，MessageBox() 显示模式对话框并运行自己的消息循环，因此您根本不需要手动处理 WM_TIMER。您可以为计时器分配一个回调，让模态循环为您调度回调事件。

试试像这样的东西：

#include <Windows.h> thread_local int MsgBox_X; thread_local int MsgBox_Y; thread_local int NumMsgBoxes = 0; static LRESULT CALLBACK CBTSetPosProc(int nCode, WPARAM wParam, LPARAM lParam) { if (nCode == HCBT_CREATEWND) { CBT_CREATEWND* s = (CBT_CREATEWND*)lParam; if (s->lpcs->hwndParent == NULL) { s->lpcs->x = MsgBox_X; s->lpcs->y = MsgBox_Y; } } return CallNextHookEx(NULL, nCode, wParam, lParam); } int MessageBoxPos(HWND hWnd, LPCTSTR lpText, LPCTSTR lpCaption, UINT uType, int X, int Y) { HHOOK hHook = SetWindowsHookEx(WH_CBT, &CBTSetPosProc, NULL, GetCurrentThreadId()); MsgBox_X = X; MsgBox_Y = Y; int result = MessageBox(hWnd, lpText, lpCaption, uType); if (hHook) UnhookWindowsHookEx(hHook); return result; } static void CALLBACK TimerProc(HWND, UINT, UINT_PTR, DWORD) { if (NumMsgBoxes > 0) { --NumMsgBoxes; MessageBoxPos(NULL, TEXT("Message 2"), TEXT("MsgBox 2"), MB_ICONWARNING | MB_OK, 50, 50); } } void _MessageBox(int NumberOfMsgBoxes) { NumMsgBoxes = NumberOfMsgBoxes; if (NumMsgBoxes > 0) { --NumMsgBoxes; UINT timer = SetTimer(NULL, 0, 2000, &TimerProc); if (timer) { MessageBox(NULL, TEXT("Message"), TEXT("MsgBox"), MB_ICONWARNING | MB_OK); KillTimer(NULL, timer); } } } int main() { ShowWindow(GetConsoleWindow(), SW_HIDE); _MessageBox(5); }

或者：

#include <Windows.h> thread_local int MsgBox_X; thread_local int MsgBox_Y; thread_local int NumMsgBoxes = 0; static LRESULT CALLBACK CBTSetPosProc(int nCode, WPARAM wParam, LPARAM lParam) { if (nCode == HCBT_CREATEWND) { CBT_CREATEWND* s = (CBT_CREATEWND*)lParam; if (s->lpcs->hwndParent == NULL) { s->lpcs->x = MsgBox_X; s->lpcs->y = MsgBox_Y; } } return CallNextHookEx(NULL, nCode, wParam, lParam); } int MessageBoxPos(HWND hWnd, LPCTSTR lpText, LPCTSTR lpCaption, UINT uType, int X, int Y) { HHOOK hHook = SetWindowsHookEx(WH_CBT, &CBTSetPosProc, NULL, GetCurrentThreadId()); MsgBox_X = X; MsgBox_Y = Y; int result = MessageBox(hWnd, lpText, lpCaption, uType); if (hHook) UnhookWindowsHookEx(hHook); return result; } static void CALLBACK TimerProc(HWND hwnd, UINT message, UINT_PTR idTimer, DWORD dwTime) { KillTimer(hwnd, idTimer); if (NumMsgBoxes > 0) MessageBoxPos(NULL, TEXT("Message 2"), TEXT("MsgBox 2"), MB_ICONWARNING | MB_OK, 50, 50); } static LRESULT CALLBACK CBTSetTimerProc(int nCode, WPARAM wParam, LPARAM lParam) { if (nCode == HCBT_CREATEWND) { CBT_CREATEWND* s = (CBT_CREATEWND*)lParam; if (s->lpcs->hwndParent == NULL) { if (--NumMsgBoxes > 0) SetTimer((HWND)wParam, 1, 2000, &TimerProc); } } return CallNextHookEx(NULL, nCode, wParam, lParam); } void _MessageBox(int NumberOfMsgBoxes) { HHOOK hHook = SetWindowsHookEx(WH_CBT, &CBTSetTimerProc, NULL, GetCurrentThreadId()); NumMsgBoxes = NumberOfMsgBoxes; if (NumMsgBoxes > 0) MessageBox(NULL, TEXT("Message"), TEXT("MsgBox"), MB_ICONWARNING | MB_OK); if (hHook) UnhookWindowsHookEx(hHook); } int main() { ShowWindow(GetConsoleWindow(), SW_HIDE); _MessageBox(5); }

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