How to safely close another application that has an exit popup without using process.Kill()

Question

I have an application that I would like to close from my current C# application. The problem is that the application I want to close has an exit confirmation that requires the user to confirm the closing of the application.

When I use this code:

foreach (Process process in runningProcesses)
{
    if (process.ProcessName == "ProcessName")
        process.CloseMainWindow();
}

the exit confirmation popup still appears on the other application.

When questions similar to this are asked elsewhere, all I can find are people suggesting process.Kill() to get past the exit confirmation. This is not an option for me as I need the other application to close down gently.

Is there a way to send a closing message to the other application that will force it to start its shutdown process without killing the process abruptly?

Answer 1

If you have to close the application gently and it displays a confirmation when trying to close it, then you'll have to handle it as well.

The actual way to do that depends on what exactly the popup is. If it's a standard dialog, something like the following could suffice:

SendMessage(hDlg, WM_COMMAND, IDOK, 0);

If it's a less standard dialog, but still using standard Windows components (like MFC or WinForms or something), you'll have to inspect its window structure (using Spy++ for example), get the handle of the button you need to press and use something like:

SendMessage(hBtn, BM_CLICK, 0, 0);

If however the dialog doesn't use standard windows (like Qt or WPF), you'll need a lot more specialized code. I'd suggest hooking into the parent dialog and pressing the button yourself to see what events are triggered (Spy++ can do that) and mimicking them with SendMessage .

Answer 2

You can send a WM_ENDSESSION message, which in most applications cause all forms to gracefully close.

PostMessage(process.MainWindowHandle, WM_ENDSESSION, IntPtr.Zero, new IntPtr(ENDSESSION_CLOSEAPP));

Definitions:

[DllImport("user32.dll")]
public static extern IntPtr PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

const int WM_ENDSESSION = 0x16;
const int ENDSESSION_CLOSEAPP = 0x1;