I need some method/event to be fired when i close my application from task manager.

Question

Hi Team,

I have the scenario like I have WPF application running on my machine with only one window.

I am making that window visibility hidden when the window got loaded.

Now have senario to fire the event/method to check the process/window got closed from task manager.

Best Regards,
Sunil

Answer 1

You will find the solution here.

Answer 2

Hi,@Sunil A M . You could use the following code to prompt the application to close with an empty window.
Codebehind:

   private void Window_Loaded(object sender, RoutedEventArgs e)  
        {  
            this.Visibility = Visibility.Hidden;  
            Window wnd = new Window();  
            wnd.Width = 0;  
            wnd.Height = 0;  
            wnd.WindowStyle = WindowStyle.None;  

            wnd.Loaded += delegate  
            {  
                HwndSource source = (HwndSource)PresentationSource.FromDependencyObject(wnd);  
              //  wnd.Visibility = Visibility.Hidden;  
                source.AddHook(WindowProc);  

            };  

            wnd.Show();  
        }  


   private static IntPtr WindowProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)  
        {  

            switch (msg)  

            {  

                case 0x11:  

                case 0x16:  
                    MessageBox.Show("Close reason: WindowsShutDown");  

                    break;  

                case 0x112:  

                    if ((LOWORD((int)wParam) & 0xfff0) == 0xf060)  
                    {  
                        MessageBox.Show("Close reason: UserClosing");  

                    }  

                    break;  

            }  

            return IntPtr.Zero;  

        }  

---

If the response is helpful, please click "Accept Answer" and upvote it.
 Note: Please follow the steps in our [documentation][5] to enable e-mail notifications if you want to receive the related email notification for this thread. 

[5]: https://learn.microsoft.com/en-us/answers/articles/67444/email-notifications.html

Answer 3

I created a WPF App (.Net Framework 4.8) using the Window_Loaded event to hide the window as shown above. Following is the process window tree shown by Spy++. The MainWindow is not visible and Spy++ is set to log all window messages that MainWindow receives.

Then I used Task Manager to End Task on WPFApp1.exe. The application closed but no window messages were seen by Spy++. It seems to me that Task Manager used TerminateProcess instead of sending a WM_SYSCOMMAND (SC_CLOSE) or WM_CLOSE message to the hidden window.

For comparison, this is what Spy++ sees when MainWindow is not hidden and the process is closed by Task Manager -

Consider a different way to allow a user to end the hidden window application -- use a notification area icon to allow the user to close the application instead of Task Manager.