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CancelEventArgs.Cancel Property

 

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

Namespace:   System.ComponentModel
Assembly:  System (in System.dll)

public bool Cancel { get; set; }

Property Value

Type: System.Boolean

true if the event should be canceled; otherwise, false.

The following example uses CancelEventArgs and a CancelEventHandler to handle the FormClosing event of a Form. This code assumes that you have created a Form with a class-level Boolean variable named isDataSaved. It also assumes that you have added a statement to invoke the OtherInitialize method from the form's Load method or the constructor (after the call to InitializeComponent).

// Call this method from the constructor of your form
    private void OtherInitialize() {
       this.Closing += new CancelEventHandler(this.Form1_Closing);
       // Exchange commented line and note the difference.
       this.isDataSaved = true;
       //this.isDataSaved = false;
    }

    private void Form1_Closing(Object sender, CancelEventArgs e) {
       if (!isDataSaved) {
          e.Cancel = true;
          MessageBox.Show("You must save first.");
       }
       else {
          e.Cancel = false;
          MessageBox.Show("Goodbye.");
       }
    }

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 3.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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