CancelEventArgs Clase

Definición

public ref class CancelEventArgs : EventArgs

public class CancelEventArgs : EventArgs

type CancelEventArgs = class
    inherit EventArgs

Public Class CancelEventArgs
Inherits EventArgs

Herencia

Object

EventArgs

CancelEventArgs

Derivado

Microsoft.VisualBasic.ApplicationServices.StartupEventArgs

System.ComponentModel.DoWorkEventArgs

System.Configuration.SettingChangingEventArgs

System.Drawing.Printing.PrintEventArgs

System.IdentityModel.Services.ErrorEventArgs

Más…

Ejemplos

En el ejemplo siguiente CancelEventArgs se usa Closing Formy para controlar el evento de un. CancelEventHandlerThe following example uses CancelEventArgs and a CancelEventHandler to handle the Closing event of a Form. En este código se supone que ha creado Form un con una variable de Boolean nivel de isDataSavedclase denominada.This code assumes that you have created a Form with a class-level Boolean variable named isDataSaved. También se supone que ha agregado una instrucción para invocar el OtherInitialize método desde el método del Load formulario o el constructor (después de la llamada InitializeComponenta).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

Comentarios

Un componente desencadena un evento cancelable cuando está a punto de realizar una acción que se puede cancelar, como el Closing evento de un. FormA cancelable event is raised by a component when it is about to perform an action that can be canceled, such as the Closing event of a Form.

CancelEventArgsproporciona la Cancel propiedad para indicar si se debe cancelar el evento.CancelEventArgs provides the Cancel property to indicate whether the event should be canceled.

Constructores

Propiedades

Métodos

Se aplica a

Consulte también:

• CancelEventHandler