Using shellexecuteex and waitforsingleobject parent window lose its focus when it returns

Question

5.00/5 (2 votes)

See more:

Using the code below to run an external exe file, when this app terminates, the parent window loses its focus. I want to disable the parent window to avoid any paint problems and re-activate when the WaitForSingleObject is terminated.

Is there any solution for that ? What am i doing wrong ?

C++

void CMainFrame::OnBtnUpdateApp() {

    SHELLEXECUTEINFO    lpExecInfo;
    DWORD               dwExitCode;
    HINSTANCE           hProcess = 0;
    BOOL                bResult;



    ZeroMemory(&lpExecInfo,sizeof(lpExecInfo));
    lpExecInfo.cbSize = sizeof(SHELLEXECUTEINFO);
    lpExecInfo.fMask = SEE_MASK_NOCLOSEPROCESS;
    lpExecInfo.hwnd = GetSafeHwnd();
    lpExecInfo.lpVerb = _T("open");
    lpExecInfo.lpFile = _T("Update.exe");
    lpExecInfo.lpParameters = _T("");
    lpExecInfo.lpDirectory = _T("");
    lpExecInfo.nShow = SW_SHOWNORMAL;
    lpExecInfo.hInstApp = NULL;
    lpExecInfo.hProcess = hProcess;

    bResult = ShellExecuteEx(&lpExecInfo);

    if(bResult) { 

         EnableWindow(FALSE);
         WaitForSingleObject( lpExecInfo.hProcess, INFINITE );

         if (!GetExitCodeProcess(lpExecInfo.hProcess, &dwExitCode)) {
                //failed to terminate normally   
         }

         CloseHandle(lpExecInfo.hProcess);
         EnableWindow(TRUE);

    } else {

        //failed to execute the exe file
    }


}

What I have tried:

I tried, BringWindowToTop(), SetActiveWindow(), SetFocus()

Posted 15-Feb-16 8:21am

sdancer75

Updated 12-Jan-18 2:54am

Add a Solution

Comments

[no name] 16-Feb-16 17:35pm

Try calling Activate after the wait or ... before the wait - save the HWND from GetFocus and (after the wait) call SetFocus on the saved HWND.

sdancer75 17-Feb-16 12:29pm

Using the code : HWND hfocus = ::GetFocus();EnableWindow(FALSE);WaitForSingleObject( lpExecInfo.hProcess, INFINITE );::SetFocus(hfocus);EnableWindow(TRUE); did not seem to work. Any other ideas ?

Frankie-C 20-Feb-16 13:50pm

You cannot set focus on a disabled window. Enable window then set focus.

sdancer75 22-Feb-16 5:22am

Yes that's true, my mistake.... but I have already did that and it didn't work.

Anyway I have some thoughts about the parent window that calls the shellexectute.
If my app is the parent window and the shellexecute app is the child window, does the switching using the keys Alt+Tab will show both parent and child apps ? This is what happens right now but I think that it would show only the parent window correct ? Does this have any relation with the focus control?

Frankie-C 22-Feb-16 5:38am

there are many tricky things related to the window state, the calling thread etc.
Have you tried using SetForegroundWindow()?

sdancer75 22-Feb-16 5:53am

Yes I used an old article from codeproject that is used the SetForegroundWindow() but I still have problem. Now I am working with CreateProcess to check if this will work for me...

Anyway do you have any idea about the question for the parent/child window if they appear as a single app in the windows application switching ?

Frankie-C 22-Feb-16 6:01am

Read the remark section in https://msdn.microsoft.com/en-us/library/windows/desktop/ms646291(v=vs.85).aspx. All child window are part of a top window enable/disable chain, but with a lot of details as usual in Win.

sdancer75 23-Feb-16 14:18pm

What ever i tried I failed. I uploaded a simple MFC/SDI file that uses CreateProcess for everyone who wants to get a look and give a solution.

http://www.filedropper.com/shellexecutecreateprocesstestapp

2 solutions

Solution 1

You will get more control over the new process you are creating if you use CreateProcess() instead of ShellExecuteEx() and running Update.exe in the background.

C++

SECURITY_ATTRIBUTES sa;
	sa.nLength = sizeof(sa);
	sa.lpSecurityDescriptor = NULL;
	sa.bInheritHandle = TRUE;

	PROCESS_INFORMATION pi;
	STARTUPINFO si;
	BOOL ret = FALSE;
	DWORD flags = CREATE_NO_WINDOW;

	ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
	ZeroMemory(&si, sizeof(STARTUPINFO));
	si.cb = sizeof(STARTUPINFO);
	si.dwFlags |= STARTF_USESTDHANDLES;
	si.hStdInput = NULL;
	si.hStdError = h;
	si.hStdOutput = h;

	CString cmd = _T("cmd /c ") + _T("Update.exe");
	BOOL inherits = FALSE;

	ret = CreateProcess(NULL,
		cmd.GetBuffer(),
		NULL,
		NULL,
		inherits,
		flags,
		NULL,
		NULL,
		&si,
		&pi);

	DWORD dwExitCode = 0;
	if (ret)
	{
		CloseHandle(pi.hProcess);
		CloseHandle(pi.hThread);
		return TRUE;
	}

Posted 11-Jan-18 8:37am

Michael Haephrati

Updated 11-Jan-18 8:38am

v2

Comments

sdancer75 12-Jan-18 8:42am

Hi, thank you for your solution. This questions is about 2 years old now, but i have already tested createprocess and shellexecute. Both of them methods loose their focus in some cases.

I found a justified solution for different cases using either shellexecute or createprocess. They seem to work fine with some restrictions.

I copied your code to verify if it works better than the code already implemented.

Michael Haephrati 12-Jan-18 8:44am

Please post an answer to your own question. It would be useful to others facing a similar problem.

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

sdancer75 · Accepted Answer · 2018-01-12T02:54:00

void CMainFrame::OnBtnUpdateApp() {


	PROCESS_INFORMATION processInfo;
	DWORD				dwExitCode;
	HANDLE				hProcess = 0;
	BOOL				bResult;
	CString				strCmd;
	CUtils				util;
	CString				strPathAndApp;


	strCmd = _T("");



	MONITORINFO mi = { sizeof(mi) };
	::GetWindowPlacement(GetSafeHwnd(), &m_g_wpPrevFrameSize) && ::GetMonitorInfo(MonitorFromWindow(GetSafeHwnd(),MONITOR_DEFAULTTOPRIMARY), &mi);

	strPathAndApp = _T("\"") + util.GetApplicationPath() + _T("\\")+_T(UPDATE_EXE_FILE) + _T("\"") + strCmd;	
	//******************************************************************************************
	//Pass the File + Parameters to cmdLine because otherwise it wont run under Winsows XP
	//******************************************************************************************
	bResult = StartupApplicationWithProcess (NULL, strPathAndApp.GetBuffer(),  &processInfo); //CreateProcess goes here
	strPathAndApp.ReleaseBuffer();


	if(bResult) { //(UINT)result > HINSTANCE_ERROR)
	
		
		AMLOGINFO(_T("LiveUpdate dialog box opened successfully."));

		DWORD dwRet;

		do {
			dwRet = ::MsgWaitForMultipleObjects(1, &processInfo.hProcess, FALSE, INFINITE, QS_ALLINPUT);
			if (dwRet != WAIT_OBJECT_0) {

				PeekMessageLoop();
			}
		} while ((dwRet != WAIT_OBJECT_0) && (dwRet != WAIT_FAILED));

		   

		
		if (!GetExitCodeProcess(processInfo.hProcess, &dwExitCode)) {
			   	AMLOGINFO(_T("LiveUpdate is not terminated normally.")); 
		}

		CloseHandle( processInfo.hProcess );
        CloseHandle( processInfo.hThread );
		



		AMLOGINFO(_T("LiveUpdate is terminated without any errors.")); 
		
		 

	} else {

		CString ErrorDescr = FormatErrorMessage(GetLastError()); 

		AfxMessageBox("Error !");
		
		
	}

    SetForegroundWindow();
    SetActiveWindow();    
	BringWindowToTop();	
	UpdateWindow();