CODEWITHSUNDEEP
c#.netwinforms
TtT23
TtT23

Reputation: 7030

How do I catch the event of exiting a Winforms application?

If the user wants to exit the application by clicking on the exit icon or by ALT+F4, I'd like to make a dialog box questioning the user if he/she is really sure about exiting.

How do I capture this event before the application is actually closed?

Upvotes: 18

Views: 36266

Answers (7)

ChemicalBlueBloo
ChemicalBlueBloo

Reputation: 1

In 2025, the WinForm event you are looking for is in the window 'Properties' -> Events -> Misc -> Closing Closing event in VS

Double click on the cell next to the name of the event to generate a Form_Closing method. The method will be called when the form is closing.

Upvotes: 0

musefan
musefan

Reputation: 48415

Check out the OnClosing event for the form.

Here is an extract from that link actually checks for a change on a text field and prompts a save:

private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
   // Determine if text has changed in the textbox by comparing to original text.
   if (textBox1.Text != strMyOriginalText)
   {
      // Display a MsgBox asking the user to save changes or abort.
      if(MessageBox.Show("Do you want to save changes to your text?", "My Application",
         MessageBoxButtons.YesNo) ==  DialogResult.Yes)
      {
         // Cancel the Closing event from closing the form.
         e.Cancel = true;
         // Call method to save file...
      }
   }
}

You can change the text to suit your needs, and then also I think you might want to switch the DialogResult.Yes to DialogResult.No based on your text.

Here is some modified code just for you:

private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
   if(MessageBox.Show("Are you sure you want to quit?", "My Application", MessageBoxButtons.YesNo) ==  DialogResult.No)
   {
      e.Cancel = true;
   }
}

Upvotes: 24

Steve
Steve

Reputation: 216293

You should subscribe to the Form_Closing event
Post a dialog box there, and if user abort the closing set the FormCloseEventArgs.Cancel to true.

For example in the Form_Load or using the designer, subscribe the event

Form1.FormClosing += new FormClosingEventHandler(Form1_Closing);

....
private void Form1_FormClosing(Object sender, FormClosingEventArgs e) 
{
    DialogResult d = MessageBox.Show("Confirm closing", "AppTitle", MessageBoxButtons.YesNo );
    if(d == DialogResult.No)
        e.Cancel = true;
}

Depending on the situation is not always a good thing to annoy the user with this kind of processing.
If you have valuable modified data and don't want the risk to loose the changes, then it is always a good thing to do, but if you use this only as a confirm of the close action then it's better to do nothing.

Upvotes: 15

Tigran
Tigran

Reputation: 62246

If you're talking about windows forms, should be enough to catch your MainWindow's

FormClosing event and in case you want prevent closing, just set the argument of the event handler got fired, to true.

Example: 

private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{

      if(MessageBox.Show("Do you really want to exit?", "My Application",
         MessageBoxButtons.YesNo) ==  DialogResult.No){

                // SET TO TRUE, SO CLOSING OF THE MAIN FORM, 
                // SO THE APP ITSELF IS BLOCKED
                e.Cancel = true;            
      }
   }
}

Upvotes: 0

Bali C
Bali C

Reputation: 31231

You can handle the Form_Closing or Form_Closed events for this.

In Visual Studio click the lightning bolt icon and scroll down to these events in the form properties list. Double click on the one you want and it will hook up the event for you.

Upvotes: 4

Jon Skeet
Jon Skeet

Reputation: 1500545

Is this just one form? If so, you might want to use the FormClosing event, which allows you to cancel it (show the dialog, then set CancelEventArgs.Cancel to true if the user chooses to cancel closing).

Upvotes: 1

Sanja Melnichuk
Sanja Melnichuk

Reputation: 3505

Read msdn sample: http://msdn.microsoft.com/en-us/library/system.windows.forms.form.closing.aspx

Upvotes: 1

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