windows MFC - 显示对话框后立即执行代码（.NET 等效于 Form.Shown）
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MFC - execute code right after dialog is shown (.NET equivalent of Form.Shown)
提问by Sumrak
I'm doing some small changes to C++ MFC project. I'm .NET developer so Windows programming is new to me.
我正在对 C++ MFC 项目做一些小的改动。我是 .NET 开发人员，所以 Windows 编程对我来说是新的。
I need to launch some method right after CDialog is completely shown (painted) for the first time, but only once.
我需要在 CDialog 第一次完全显示（绘制）后立即启动一些方法，但只有一次。
How can I do this? In .NET I would handle Form.Shownevent.
我怎样才能做到这一点？在 .NET 中，我会处理Form.Shown事件。
Do I need to handle some message? Which? Do I need to override some CDialog method? Or is there no easy way? I'm thinking of handling WM_ACTIVATE and then using a flag to ensure I call another method only once.
我需要处理一些消息吗？哪一个？我需要覆盖一些 CDialog 方法吗？还是没有简单的方法？我正在考虑处理 WM_ACTIVATE，然后使用一个标志来确保我只调用另一个方法一次。
采纳答案by Sumrak
Found the answer here: Waiting until the dialog box is displayed before doing something
在这里找到答案：等到对话框显示后再做某事
Short story:
INT_PTR CALLBACK
DlgProc(HWND hwnd, UINT uiMsg, WPARAM wParam, LPARAM lParam)
{
switch (uiMsg) {
case WM_INITDIALOG:
return TRUE;
case WM_WINDOWPOSCHANGED:
if ((((WINDOWPOS*)lParam)->flags & SWP_SHOWWINDOW) &&
!g_fShown) {
g_fShown = TRUE;
PostMessage(hwnd, WM_APP, 0, 0);
}
break;
case WM_APP:
MessageBox(hwnd,
IsWindowVisible(hwnd) ? TEXT("Visible")
: TEXT("Not Visible"),
TEXT("Title"), MB_OK);
break;
case WM_CLOSE:
EndDialog(hwnd, 0);
break;
}
return FALSE;
}
If you're using MFC like I am you'll need to map WM_WINDOWPOSCHANGED and then use ON_MESSAGE to map WM_APP. See this CodeProject articlefor more details.
如果您像我一样使用 MFC，则需要映射 WM_WINDOWPOSCHANGED，然后使用 ON_MESSAGE 映射 WM_APP。有关更多详细信息，请参阅此 CodeProject 文章。
回答by Joel Lucsy
Another approach I've used a number of times with great success is to use a timer. Set it for 10m0s. It'll only fire after the dialog is shown.
我多次使用并取得巨大成功的另一种方法是使用计时器。将其设置为 10m0s。它只会在显示对话框后触发。
回答by baash05
Hell put the code in OnPaint() and thow a bool m_fullyInitilized in your class. I like the timer too.. Though I usually go with 100ms. I also move all my initilization code out of the oninit, in these cases.. Just to protect against too much processing in there.
地狱把代码放在 OnPaint() 中，并在你的类中放一个 bool m_fullyInitilized 。我也喜欢计时器..虽然我通常用 100 毫秒。在这些情况下，我还将所有初始化代码从 oninit 中移出。只是为了防止在那里进行过多的处理。
回答by SteveH
For reference you don't need to override DlgProc to intercept WM_WINDOWPOSCHANGED.
作为参考，您不需要覆盖 DlgProc 来拦截 WM_WINDOWPOSCHANGED。
ON_WM_WINDOWPOSCHANGED()
ON_MESSAGE(MyCDialog::MY_USER_MSG, OnDialogShown)
void MyCDialog::OnWindowPosChanged(WINDOWPOS *wndpos)
{
__super::OnWindowPosChanged(wndpos);
if (!mDialogShown && (wndpos->flags & SWP_SHOWWINDOW)) {
PostMessage(MY_USER_MSG);
mDialogShown = true;
}
}
LRESULT MyCDialog::OnDialogShown(WPARAM, LPARAM)
{
...
}
You can implement the handling inline instead of posting another message if appropriate.
如果合适，您可以实施内联处理而不是发布另一条消息。
