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CancelEventArgs.Cancel Property
.NET Framework (current version)
Gets or sets a value indicating whether the event should be canceled.
Assembly: System (in System.dll)
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
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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