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ConsoleCancelEventHandler (Delegado)

Nota: este delegado es nuevo en la versión 2.0 de .NET Framework.

Representa el método que controlará el evento CancelKeyPress de System.Console.

Espacio de nombres: System
Ensamblado: mscorlib (en mscorlib.dll)

public delegate void ConsoleCancelEventHandler (
	Object sender,
	ConsoleCancelEventArgs e
)
/** @delegate */
public delegate void ConsoleCancelEventHandler (
	Object sender, 
	ConsoleCancelEventArgs e
)
JScript admite el uso de delegados, pero no admite la declaración de delegados nuevos.

Parámetros

sender

Origen del evento.

e

Objeto System.ConsoleCancelEventArgs que contiene los datos del evento.

Cuando se crea un delegado de ConsoleCancelEventHandler, se identifica el método que controlará el evento. Para asociar el evento a su controlador, agregue una instancia del delegado al evento. Siempre que se produce el evento, se llama a su controlador, a menos que se quite el delegado. Para obtener más información sobre los delegados de controladores de eventos, vea Eventos y delegados.

El ejemplo de código siguiente muestra cómo utilizar la clase ConsoleCancelEventHandler para controlar un evento.

// This example demonstrates:
// the Console.CancelKeyPress event,
// the ConsoleCancelEventHandler delegate, 
// the ConsoleCancelEventArgs.SpecialKey property, and 
// the ConsoleCancelEventArgs.Cancel property.

using System;

class Sample 
{
    public static void Main()
    {
    ConsoleKeyInfo cki;

// Clear the screen.
    Console.Clear();

// Turn off the default system behavior when CTRL+C is pressed. When 
// Console.TreatControlCAsInput is false, CTRL+C is treated as an
// interrupt instead of as input.
    Console.TreatControlCAsInput = false;

// Establish an event handler to process key press events.
    Console.CancelKeyPress += new ConsoleCancelEventHandler(myHandler);
    while (true)
        {
// Prompt the user.
        Console.Write("Press any key, or 'X' to quit, or ");
        Console.WriteLine("CTRL+C to interrupt the read operation:");

// Start a console read operation. Do not display the input.
        cki = Console.ReadKey(true);

// Announce the name of the key that was pressed .
        Console.WriteLine("  Key pressed: {0}\n", cki.Key);

// Exit if the user pressed the 'X' key.
        if (cki.Key == ConsoleKey.X) break;
        }
    }

/*
   When you press CTRL+C, the read operation is interrupted and the 
   console cancel event handler, myHandler, is invoked. Upon entry 
   to the event handler, the Cancel property is false, which means 
   the current process will terminate when the event handler terminates. 
   However, the event handler sets the Cancel property to true, which 
   means the process will not terminate and the read operation will resume.
*/
    protected static void myHandler(object sender, ConsoleCancelEventArgs args)
    {
// Announce that the event handler has been invoked.
    Console.WriteLine("\nThe read operation has been interrupted.");

// Announce which key combination was pressed.
    Console.WriteLine("  Key pressed: {0}", args.SpecialKey);

// Announce the initial value of the Cancel property.
    Console.WriteLine("  Cancel property: {0}", args.Cancel);

// Set the Cancel property to true to prevent the process from terminating.
    Console.WriteLine("Setting the Cancel property to true...");
    args.Cancel = true;

// Announce the new value of the Cancel property.
    Console.WriteLine("  Cancel property: {0}", args.Cancel);
    Console.WriteLine("The read operation will resume...\n");
    }
}
/*
This code example produces results similar to the following text:

Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
  Key pressed: J

Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
  Key pressed: Enter

Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:

The read operation has been interrupted.
  Key pressed: ControlC
  Cancel property: False
Setting the Cancel property to true...
  Cancel property: True
The read operation will resume...

  Key pressed: Q

Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
  Key pressed: X

*/

Windows 98, Windows 2000 SP4, Windows Millennium, Windows Server 2003, Windows XP Media Center, Windows XP Professional x64, Windows XP SP2, Windows XP Starter Edition

.NET Framework no admite todas las versiones de cada plataforma. Para obtener una lista de las versiones admitidas, vea Requisitos del sistema.

.NET Framework

Compatible con: 2.0
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