Is there a way to loop through all MFC Child Dialogs, MDI frames and etc? And is there a way to find out which dialog or window I am looping through?
Taken from Анатолий Тутов (https://web.archive.org/web/20140110220804/http://www.asis.ru/posts/27):
for (CWnd *pWnd = GetWindow(GW_CHILD); pWnd != NULL; pWnd = pWnd->GetNextWindow(GW_HWNDNEXT))
{
//Insert your code here. pWnd is a pointer to control window.
}
You could use EnumChildWindows to iterate through child windows of certain window.
Related
I have a 32-bit MFC application that uses a custom library that would be a nightmare to re-compile into x64. In general the app doesn't really need to run as 64-bit, except in one case -- and that is to render contents to display in a dialog window, which can benefit from a larger addressing space.
So my goal is to "imitate" CDialog::DoModal method but for a dialog in another process.
I built that dialog window as a standalone x64 MFC dialog-based application. It takes a file path as it's input parameter, does all the work internally, and returns simple user selection: OK, Cancel.
So I do the following from my main parent process:
//Error checks omitted for brevity
CString strCmd = L"D:\\C++\\MyDialogBasedApp.exe";
HWND hParWnd = this->GetSafeHwnd();
SHELLEXECUTEINFO sei = {0};
sei.cbSize = sizeof(sei);
sei.fMask = SEE_MASK_FLAG_NO_UI | SEE_MASK_UNICODE | SEE_MASK_NOCLOSEPROCESS;
sei.nShow = SW_SHOW;
sei.lpVerb = _T("open");
sei.lpFile = strCmd.GetBuffer();
sei.hwnd = hParWnd;
BOOL bInitted = SUCCEEDED(::CoInitializeEx(NULL, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE));
ShellExecuteEx(&sei);
DWORD dwProcID = ::GetProcessId(sei.hProcess);
//Try to get main Wnd handle for the child process
HWND hMainChildWnd = NULL;
for(;; ::Sleep(100))
{
hMainChildWnd = getHwndFromProcID(dwProcID);
if(hMainChildWnd)
break;
}
HWND hPrevParWnd = ::SetParent(hMainChildWnd, hParWnd);
if(hPrevParWnd)
{
//Wait for child process to close
::WaitForSingleObject(sei.hProcess, INFINITE);
//Reset parent back
::SetParent(hMainChildWnd, hPrevParWnd);
}
::CloseHandle(sei.hProcess);
if(bInitted)
::CoUninitialize();
where getHwndFromProcID is taken from here.
This kinda works, except of the following:
(1) There are two icons on the taskbar: one for my main app, and one for the child app. Is there a way not to show a child icon?
(2) I can switch focus from child window to parent and vice versa. In actual modal dialog window one cannot switch back to parent while child is open. Is there a way to do that?
(3) If I start interacting with the parent, it appears to be "hung up" and the OS will even show it on its title bar.
So I was curious if there's a way to resolve all these?
you need pass pointer of own window to child process
you need process windows messages, while you wait on child process
exit. WaitForSingleObject unacceptably here - need use
MsgWaitForMultipleObjectsEx
child process must set your window as self owner window at create
time - you not need call SetParent
with this all will be worked perfect. in your 32-bit MFC application you need use next code :
BOOL DoExternalModal(HWND hwnd, PCWSTR ApplicationName)
{
STARTUPINFO si = { sizeof(si) };
PROCESS_INFORMATION pi;
WCHAR CommandLine[32];
swprintf(CommandLine, L"*%p", hwnd);
if (CreateProcessW(ApplicationName, CommandLine, 0, 0, 0, 0, 0, 0, &si, &pi))
{
CloseHandle(pi.hThread);
MSG msg;
for (;;)
{
switch (MsgWaitForMultipleObjectsEx(1, &pi.hProcess, INFINITE, QS_ALLINPUT, 0))
{
case WAIT_OBJECT_0:
CloseHandle(pi.hProcess);
return TRUE;
case WAIT_OBJECT_0 + 1:
while (PeekMessage(&msg, 0, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
continue;
default: __debugbreak();
}
}
}
return FALSE;
}
in MyDialogBasedApp.exe let use MessageBox as demo dialog. we will be use your MFC window as first argument to it.
void ExeEntry()
{
int ec = -1;
if (PWSTR CommandLine = GetCommandLine())
{
if (CommandLine = wcschr(CommandLine, '*'))
{
HWND hwnd = (HWND)(ULONG_PTR)_wcstoi64(CommandLine + 1, &CommandLine, 16);
if (hwnd && !*CommandLine && IsWindow(hwnd))
{
ec = MessageBoxW(hwnd, L"aaa", L"bbb", MB_OK);
}
}
}
ExitProcess(ec);
}
with this code:
(1) There are only one icon on the taskbar for your main app
(2) You can not switch focus from child window to parent and vice versa. all work as actual modal dialog window
(3) parent not "hung up" because it processing windows messages (MsgWaitForMultipleObjectsEx) - your code is "hung up" because you not do this, but wait in WaitForSingleObject
A modal dialog box does two things that make it "modal":
The dialog's "owner" is set to the parent window.
The parent window is disabled.
I played around with this a little bit and while you can do these manually, the easiest way is to just pass the parent window handle to the DialogBox function (or the CDialog constructor in MFC).
Instead of doing all the work after ShellExecuteEx in the parent process, your child process can use FindWindow (or a similar mechanism) to get the parent window handle and use that to display the dialog.
What you are trying to do cannot safely be done. The blog entry Is it legal to have a cross-process parent/child or owner/owned window relationship? explains, that installing a cross-process owner/owned window relationship causes the system to call AttachThreadInput, and - as we all know - AttachThreadInput is like taking two threads and pooling their money into a joint bank account, where both parties need to be present in order to withdraw any money. This creates a very real potential for a dead lock. You can only safely prevent this from happening, if you control both participating threads. Since at least one thread uses a 3rd party application framework (MFC in this case), this is off limits.
Since we have established, that your proposed solution cannot safely be implemented, you need to look into alternatives. One solution might be to delegate the work to a 64-bit process for computation, and have the results passed back to your 32-bit process for display.
I created child window (dialog) end set it's parent the window of another process (Notepad for example) by its handle.
HANDLE hProcess = OpenProcess( PROCESS_QUERY_INFORMATION |
PROCESS_VM_READ,
FALSE, processID );
if (NULL != hProcess )
{
HWND hw;
hw = find_main_window(processID); //some function of getting win handle through process ID
}
................
CMyHud *mhDlg = new CMyHud();
CWnd* pWnd = CWnd::FromHandle(hw);
//if(mhDlg->m_hWnd != 0)
if (!mhDlg->GetSafeHwnd())
{
if (mhDlg != NULL)
{
ret = mhDlg->Create(IDD_DIALOG1, pWnd);
}
if (!ret) //Create failed.
{
AfxMessageBox(_T("Error creating Dialog"));
return FALSE;
}
}
Then I set styles for parent and child windows
LONG t = GetWindowLong(hw,GWL_STYLE) | WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
SetWindowLong(hw,GWL_STYLE,t);
LONG t1 = GetWindowLong(mhDlg->m_hWnd,GWL_STYLE) | WS_CLIPSIBLINGS | WS_OVERLAPPED;
SetWindowLong(mhDlg->m_hWnd,GWL_STYLE,t1);
::BringWindowToTop(mhDlg->m_hWnd);
mhDlg->ShowWindow(SW_SHOW);
The child window appears in the client area of the parent window (Notepad).
Good.
BUT! It's disappears when I set focus on parent window. Well. Physically it's still there, but its background merges with parent's window background, and it seems like the child window is gone.
When you find child window and set focus on it, it's appearing again. But it is redrawing bad, still having a parts of parent's window background (look at the picture).
What have i done wrong?? What should I do for appearing child window over the parent ALWAYS, regardless of redrawing the parent window?
With using the SetWindowPos method all works perfectly!
I want to get handle of child window, but cannot.
I want to automatically insert text in an Edit control.
Here is what I have:
//global var
int id=0;
BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam) {
id = GetDlgCtrlID(hwnd);
HWND hwnd_Child;
hwnd_Child = GetDlgItem(hwnd, id);
SendMessage(hwnd_Child, WM_SETTEXT, NULL, (LPARAM)"mYtexttttt");
/* other code */
// id is always 0, why ?
// return FALSE; // stop enumerating
return TRUE; // continue enumeration
}
void MyFunction ()
{
HWND hwnd_Parent;
hwnd_Parent = FindWindow(NULL,"MyTitle"); if(! hwnd)return;
EnumChildWindows(hWnd ,(WNDENUMPROC)EnumWindowsProc, NULL);
}
In WinSpy++, the control IDs of all the components are 000000000. Is it possible that the control ID isn't defined?
How do I find the child handle of some specific (edit box) component if I have the handle of the main window, and the control ID is not defined?
Also, main window is a game application which runs with DirectX, I think.
I want to automatically insert text in a Edit control.
If WinSpy tells you that the control IDs are 0 then getting a 0 back from GetDlgCtrlID() is of course the expected outcome. You'll have to do something else, like counting down the number of EnumWindowsProc() calls and/or calling GetClassName() so you can see it is an edit control. Or GetWindowRect() to go by position.
In your callback method, please do the following:
// get the window text
GetWindowText(hWnd, (LPTSTR)windowText, MAX_PATH);
// get the window info
WINDOWINFO objWinInfo;
GetWindowInfo(hWnd, &objWinInfo)
The above should help you get the child windows.
Also you can do FindWindowEx to the get the child windows.
Control ids are one convenient way to identify child windows; but not the only way. So it is quite possible that control id will be set to arbitrary (or zero) values (in which case the parent window just refers to them directly by their handles.
From your point of view if no control ids exist you must reference them by the position in the tab sequence which should be constant and can be iterated through.
I need to get the current foreground window handle and compare it to a saved previous window handle to see if they match, but I can't use foreground window title, because the title changes often
This is the code I'm using to compare the titles
char cWindow[MAX_PATH];
char nWindow[MAX_PATH];
GetWindowTextA(GetForegroundWindow(), cWindow, sizeof(cWindow));
//Later in code
GetWindowTextA(GetForegroundWindow(), cWindow, sizeof(cWindow));
if (strcmp(nWindow, cWindow) != 0)
{
fputs("found!",file);
strcpy(nWindow, cWindow);
}
When you want to check whether the foreground window has changed, you should compare the window handles directly, without their titles.
HWND oldForegroundWindow = GetForegroundWindow();
HWND newForegroundWindow = GetForegrundWindow();
if (newForegroundWindow != oldForegroundWindow) {
ForegroundWindowHasChanged(oldForegroundWindow, nForegroundWindow);
oldForegroundWindow = newForeroundWindow;
}
Errr you are NOT setting nWindow to anything both your calls are setting cWindow. Do you think that may be an issue?
In VC++, I use EnumWindows(...), GetWindow(...), and GetWindowLong(), to get the list of windows and check whether the window is top window (no other window as owner), and whether the window is visible (WS_VISIBLE). However, although my desktop is showing only 5 windows, this EnumWindows is giving me 50 windows, how funny! Any Windows geek here please help me clarify...
The way to list out only windows in taskbar (or similarly in Alt-Tab box) is described by Raymond in this article on MSDN blog:
Which windows appear in the Alt+Tab list?
And this is the super function to check whether a window is shown in alt-tab:
BOOL IsAltTabWindow(HWND hwnd)
{
TITLEBARINFO ti;
HWND hwndTry, hwndWalk = NULL;
if(!IsWindowVisible(hwnd))
return FALSE;
hwndTry = GetAncestor(hwnd, GA_ROOTOWNER);
while(hwndTry != hwndWalk)
{
hwndWalk = hwndTry;
hwndTry = GetLastActivePopup(hwndWalk);
if(IsWindowVisible(hwndTry))
break;
}
if(hwndWalk != hwnd)
return FALSE;
// the following removes some task tray programs and "Program Manager"
ti.cbSize = sizeof(ti);
GetTitleBarInfo(hwnd, &ti);
if(ti.rgstate[0] & STATE_SYSTEM_INVISIBLE)
return FALSE;
// Tool windows should not be displayed either, these do not appear in the
// task bar.
if(GetWindowLong(hwnd, GWL_EXSTYLE) & WS_EX_TOOLWINDOW)
return FALSE;
return TRUE;
}
Credited to the source code here:
http://www.dfcd.net/projects/switcher/switcher.c
The windows that you are talking about, with an X button and a title bar, etc. are not the only kind of windows. Buttons, dropdown menus, labels, icons, text boxes, the task bar, and just about everything else is a window too1. So EnumWindows is doing exactly what it's supposed to do: enumerate all the top level windows.
1 Even though this is true, EnumWindows only enumerates the top level windows. That means it won't enumerate any child windows:
The EnumWindows function does not enumerate child windows, with the exception of a few top-level windows owned by the system that have the WS_CHILD style.
However, many things on your desktop are windows as well, not just the "windows" you're thinking about.
The answer provided by #jondinham does work perfectly for me. So I work out my own solution.
1.Problems I met with previous solution
Running on Windows 10 home edition 1909., I get two extra unexpected Windows "Calculator" and "Setting".
In addition, windows of Tencent QQ can not be detected, because the following fails:
// the following removes some task tray programs and "Program Manager"
ti.cbSize = sizeof(ti);
GetTitleBarInfo(hwnd, &ti);
if(ti.rgstate[0] & STATE_SYSTEM_INVISIBLE)
return FALSE;
However, I think the bug may be resulted by the particularity of Tencent QQ, I can not even make its' window TOPMOST with DeferWindowPos.
Perhaps someone can help me figure out why this happened and help improving the previous solution by #jondinham.
2.My Solution
I tried to examing the icons of the windows, and filter out windows that does not have its own icon or uses the icon same as the system default. I use code snippets from answer and answer and do some modification. This solution works very well for me.
HICON get_windows_HICON_critical(HWND hwnd)
{
// Get the window icon
HICON icon = reinterpret_cast<HICON>(::SendMessageW(hwnd, WM_GETICON, ICON_SMALL, 0));
if (icon == 0) {
// Alternative method. Get from the window class
icon = reinterpret_cast<HICON>(::GetClassLongPtrW(hwnd, GCLP_HICONSM));
}
// Alternative method: get the first icon from the main module (executable image of the process)
if (icon == 0) {
icon = ::LoadIcon(GetModuleHandleW(0), MAKEINTRESOURCE(0));
}
// // Alternative method. Use OS default icon
// if (icon == 0) {
// icon = ::LoadIcon(0, IDI_APPLICATION);
// }
if(icon == ::LoadIcon(0, IDI_APPLICATION)){
// Filter out those with default icons
icon = 0;
}
return icon;
}
static BOOL CALLBACK enumWindowCallback(HWND hWnd, LPARAM lparam) {
int length = GetWindowTextLength(hWnd);
char* buffer = new char[length + 1];
GetWindowText(hWnd, buffer, length + 1);
std::string windowTitle(buffer);
// List visible windows with a non-empty title
if (IsWindowVisible(hWnd) && length != 0) {
HICON icon = get_windows_HICON_critical(hWnd);
if(icon!=0){
std::cout << hWnd << ": " << windowTitle << std::endl;
}
}
return TRUE;
}
3.Problems with my solution
My solution can not deal with Windows Store APP, according to this question.
For all people looking to find a way to remove Invisible windows like Settings or Microsoft Store from the list:
These windows are cloaked, meaning they still have the dwStyle WS_VISIBLE, but the user can't see them.
You can detect this using the function DwmGetWindowAttribute. The dwAttribute you want to get is DWMWA_CLOAKED (enum constant 14). Only if the value in pvAttribute after the method call is 0, the window is not cloacked.