child form closing when it should not

  • Thread starter Thread starter Bamse
  • Start date Start date
B

Bamse

hi,
I have 2 forms, one is MDI, one is child of the before mentioned one;
when the user tries to close the child, the form is checked whether the data
within changed;
if data changed, the user is prompted to: Save/Not Save/Cancel

if Save is clicked - the data is saved and the form closes
if Not save is clicked - the data is not saved and the form closes
if Cancel is clicked - the data is not saved and the form should NOT close

I've overrided OnClosing() and made a function which returns false if the
user choosed Cancel, setting e.Cancel = true to cancel closing

protected override OnClosing(System.ComponentModel.CancelEventArgs e)
{
if (!IsOkToClose())
e.Cancel = true;
//base.OnClosing(e);
}

this method is mentioned in many sources (MSDN, google, etc)
still, this code does not work, the form closes anyway

someone can help?

Thank you,
Daniel
 
Hi Daniel,

Are you sure IsOkToClose() returns the proper value? You can put a breakpoint on the e.Cancel to see if it is ever called (or put a messagebox inside the if brackets).

Happy coding!
Morten Wennevik [C# MVP]
 
Well, I can't verify your problem, using the following code in either overriden or subscribed closing event.

DialogResult result = MessageBox.Show(this,
"Do you want to save your work?", "MyApp",
MessageBoxButtons.YesNoCancel,
MessageBoxIcon.Question,
MessageBoxDefaultButton.Button1);

switch(result)
{
case DialogResult.Yes:
// do save stuff
// clean up?
break;
case DialogResult.No:
// clean up?
break;
case DialogResult.Cancel:
e.Cancel = true;
break;
}

Could you provide us with some more code or details?

Happy coding!
Morten Wennevik [C# MVP]
 
if the data is saved/not saved, IsSafeToClose() returns true;
if the user clicks Cancel, IsSafeToClose() returns false;



protected override void OnClosing(System.ComponentModel.CancelEventArgs
ce)
{
ce.Cancel = (!this.IsSafeToClose());
base.OnClosing(ce);
}

I can't put the code whicch checks the data changes because the function
is called from another point in form, when the user closes the current
set of data/opens another one

the issue is that, ce.Cancel is set to true, but the form still unloads
 
Sorry, can't help you. The only way I can think of this happening is if the closing event is called two or more times where the later event passes through the check (like accidentally calling Close() at a point where it is close to safe but user didn't close).

Happy coding!
Morten Wennevik [C# MVP]
 
another issue is that when clicking 'X' button, the code works; when
clicking the "Exit" button which is set as the CancelButton of the form, the
code does not work
 
? CancelButton. If by that you mean a button set to DialogResult.Cancel you need to call close in the button's click event.

Happy coding!
Morten Wennevik [C# MVP]
 
Ah, setting a button to Cancel has the effect of setting DialogResult.Cancel, you have to call this.Close() in the button event.

Happy coding!
Morten Wennevik [C# MVP]
 
yes, a WindowsForm has 2 properties, AcceptButton - button 'clicked' when
the user presses "Enter" and CancelButton for "Esc"

Morten Wennevik said:
? CancelButton. If by that you mean a button set to DialogResult.Cancel
Click to expand...
you need to call close in the button's click event.
Happy coding!
Morten Wennevik [C# MVP]
Click to expand...
 
My bad *blush*. Yeah, the CancelButton. Trying it on a form using ShowDialog and clicking a button set as CancelButton caused a Closing event which handled e.Cancel as expected. I'm not sure why it doesn't work for you :(

Happy coding!
Morten Wennevik [C# MVP]
 
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