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ConsoleCancelEventArgs.Cancel Property

Gets or sets a value indicating whether simultaneously pressing the Control modifier key and C console key (CTRL+C) terminates the current process.

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

public bool Cancel { get; set; }

Property Value

Type: System.Boolean
true if the current process should resume when the event handler concludes; false if the current process should terminate.

ExceptionCondition
InvalidOperationException

true was specified in a set operation and the event was caused by simultaneously pressing the Control modifier key and the BREAK console key (CTRL+BREAK).

The Cancel property is automatically initialized to false when the handler for the CancelKeyPress event is invoked. The value of the Cancel property when the event handler finishes determines whether the current process resumes or terminates.

In a set operation after CTRL+C is pressed, specify true to indicate that the current process should resume when the event handler concludes, or false to indicate that the current process should terminate.

In a set operation after CTRL+BREAK is pressed, the current process terminates regardless of the setting of the Cancel property. That is, you cannot prevent the current process from terminating if CTRL+BREAK is pressed. Furthermore, there is no effect if you set the Cancel property to false, but an exception is thrown if you specify true.

The following code example demonstrates how to use the Cancel property to handle an event.

using System;

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

        Console.Clear();

        // Establish an event handler to process key press events.
        Console.CancelKeyPress += new ConsoleCancelEventHandler(myHandler);
        while (true) {
            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");
    }
}
// The example displays output similar to the follwoing: 
//    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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

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