How to control desktop application when user terminates from task mngr

Question

Hello All, How to control desktop application when user terminates from task manager because application is loosing data

Rajanikant Hawaldar · Answer

Hello sanjay, There is no reliable way to do this. The user can always end up whatever he wants. In some situations it is possible to capture a Windows message and do something. But there is no guarantee that this message will be sent by Windows. It depends on how the user is terminating the process. It does not even have to be the task manager. I suggest you to convience or restrict the user not terminate app from task manager. Also use as @Nitin said UI notations. Lets say tomorrow your client click save button then turn off system then what will you do?. End process work is to kill process that can be any process. Hope you understand my point. Raymond Chen said : If a user fires up Task Manager and clicks “End Task” on your program, Windows first tries to shut down your program nicely, by sending WM_CLOSE messages to GUI programs and CTRL_CLOSE_EVENT events to console programs. But you don’t get a chance to intercept TerminateProcess. Why not? TerminateProcess is the low-level process killing function. It bypasses DLL_PROCESS_DETACH and anything else in the process. Once you kill with TerminateProcess, no more user-mode code will run in that process. It’s gone. If you could intercept TerminateProcess, then you would be escalating the arms race between programs and users. Suppose you could intercept it. Well, then if you wanted to make your program unkillable, you would just hang in your TerminateProcess handler! And then people would ask for “a way to kill a process that is refusing to be killed with TerminateProcess,” and we’d be back to where we started.

Sachin Singh · Answer

you need to properly handle different closing scenario that may occur for example force close by task manager. you can handle it like given in the example below protected override void OnClosing(CancelEventArgs e) { //Your alternate implementation FormClosingEventArgs ce = e as FormClosingEventArgs; if (ce != null ) { //Handle ce } base .OnClosing(e); } private void SampleForm_FormClosing( object sender, FormClosingEventArgs e) { //Your alternate implementation } switch (ce.CloseReason) { case CloseReason.ApplicationExitCall: //Handle application exit call break ; case CloseReason.FormOwnerClosing: //Handle Form owner close break ; case CloseReason.MdiFormClosing: //Handle MDI parent closing break ; case CloseReason.None: //Handle unknown reason break ; case CloseReason.TaskManagerClosing: //Handle taskmanager close break ; case CloseReason.UserClosing: Handle User close break ; case CloseReason.WindowsShutDown: //Handle system shutdown break ; }

Sachin Singh · Answer

idk why but yes the flow directly goes to user closing , it is unexpected behaviour though, perhaps windows have new rules (i think the same works for windows 7 )

Nitin Sontakke · Answer

I just checked and yes, you are right, it doesn't seem to work. So may be, you will need to understand why user is doing that and give some sort of UI indication that data is being saved. Are they thinking that it is hanged? Are you showing progress / can show progress? There are definitely better ways to handle this scenario, I think.

Sanjay Kumar · Answer

Thank you all your help

Nitin Sontakke · Answer

Turning off the system is good scenario!

Sanjay Kumar · Answer

I will convince client not terminate app and ask to disable task manager for that user. Thanks for more info @Rajanikant, Nitin, Sachin

Nitin Sontakke · Answer

User don't want to see the progress bar. Doesn't want to know that application is processing and want to go in task bar and close it. Hummm... If someone is bent on to not using the system, you cannot really force, can you?

Sanjay Kumar · Answer

@Nitin showing progress bar is good idea because user will come to know but not acceptable by client

Sanjay Kumar · Answer

@Sachin I use Windows 10 OS, I put your code message will display then immediately app closes

Sachin Singh · Answer

you should try something like rivate void Form1_FormClosing(object sender, FormClosingEventArgs e) { // Display a MsgBox asking the user to close the form. if (MessageBox.Show( "Are you sure you want to close the form?" , "Close Form" , MessageBoxButtons.YesNo,MessageBoxIcon.Question) == DialogResult. No ) { // Cancel the Closing event e.Cancel = true ; } }

Sanjay Kumar · Answer

@Nitin my desktop application should not be closed when my client terminates app from task manager how do I restrict this? Because user clicked on save button then tried to terminated app from task manager he was added 300 hundred rows of data in datagridview(there are many validations on each columns wise). Issue is all rows not saved to db so they want app to ask permission when user try ti terminate app from task manager. I have tried with @sachin code debugger will hit form closing event then it hit case CancelReason.UserClosing then immediately app closes.

Nitin Sontakke · Answer

"This is not working" doesn't tell much. If you could please explain what you want to achieve and share a piece of code which is not working as expected that would be nice.

Sanjay Kumar · Answer

@Sachin this is not working I tried this before