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Form.Closing Event

Occurs when the form is closing.

[Visual Basic]
Public Event Closing As CancelEventHandler
[C#]
public event CancelEventHandler Closing;
[C++]
public: __event CancelEventHandler* Closing;

[JScript] In JScript, you can handle the events defined by a class, but you cannot define your own.

Event Data

The event handler receives an argument of type CancelEventArgs containing data related to this event. The following CancelEventArgs property provides information specific to this event.

Property Description
Cancel Gets or sets a value indicating whether the event should be canceled.

Remarks

The Closing event occurs as the form is being closed. When a form is closed, all resources created within the object are released and the form is disposed. If you cancel this event, the form remains opened. To cancel the closure of a form, set the Cancel property of the CancelEventArgs passed to your event handler to true.

When a form is displayed as a modal dialog box, clicking the Close button (the button with an X at the upper-right corner of the form) causes the form to be hidden and the DialogResult property to be set to DialogResult.Cancel. You can override the value assigned to the DialogResult property when the user clicks the Close button by setting the DialogResult property in an event handler for the Closing event of the form.

Note   When the Close method is called on a Form displayed as a modeless window, you cannot call the Show method to make the form visible, because the form's resources have already been released. To hide a form and then make it visible, use the Control.Hide method.
CAUTION   The Form.Closed and Form.Closing events are not raised when the Application.Exit method is called to exit your application. If you have validation code in either of these events that must be executed, you should call the Form.Close method for each open form individually before calling the Exit method.

If the form is an MDI parent form, the Closing events of all MDI child forms are raised before the MDI parent form's Closing event is raised. In addition, the Closed events of all MDI child forms are raised before the Closed event of the MDI parent form is raised. Canceling the Closing event of an MDI child form does not prevent the Closing event of the MDI parent form from being raised. However, cancelling the event will set to false the System.Windows.Forms.ClosingEventArgs.Cancel property of the System.Windows.Forms.ClosingEventArgs that is passed as a parameter to the parent form. To force all MDI parent and child forms to close, set the System.Windows.Forms.ClosingEventArgs.Cancel property to false in the MDI parent form.

For more information about handling events, see Consuming Events.

Example

[Visual Basic] 
Private Sub Form1_Closing(sender As Object, e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
   ' Determine if text has changed in the textbox by comparing to original text.
   If textBox1.Text <> strMyOriginalText Then
      ' 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 Then
         ' Cancel the Closing event from closing the form.
         e.Cancel = True
      End If ' Call method to save file...
   End If
End Sub 'Form1_Closing
End Class 'Form1

[C#] 
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...
      }
   }
}

[C++] 
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(S"Do you want to save changes to your text?", S"My Application",
            MessageBoxButtons::YesNo) ==  DialogResult::Yes)
         {
            // Cancel the Closing event from closing the form.
            e->Cancel = true;
            // Call method to save file...
         }
      }
   }

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

Form Class | Form Members | System.Windows.Forms Namespace | IsMdiContainer | OnClosing

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