CancelEventArgs.Cancel Property
Definition
Gets or sets a value indicating whether the event should be canceled.
public:
property bool Cancel { bool get(); void set(bool value); };
public bool Cancel { get; set; }
member this.Cancel : bool with get, set
Public Property Cancel As Boolean
Property Value
true
if the event should be canceled; otherwise, false
.
Examples
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
).
private:
// Call this method from the InitializeComponent() method of your form
void OtherInitialize()
{
this->Closing += gcnew CancelEventHandler( this, &Form1::Form1_Cancel );
this->myDataIsSaved = true;
}
void Form1_Cancel( Object^ /*sender*/, CancelEventArgs^ e )
{
if ( !myDataIsSaved )
{
e->Cancel = true;
MessageBox::Show( "You must save first." );
}
else
{
e->Cancel = false;
MessageBox::Show( "Goodbye." );
}
}
// 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.");
}
}
' Call this method from the Load method of your form.
Private Sub OtherInitialize()
' Exchange commented line and note the difference.
Me.isDataSaved = True
'Me.isDataSaved = False
End Sub
Private Sub Form1_Closing(sender As Object, e As _
System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
If Not isDataSaved Then
e.Cancel = True
MessageBox.Show("You must save first.")
Else
e.Cancel = False
MessageBox.Show("Goodbye.")
End If
End Sub