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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;
        }
    }

    protected static void myHandler(object sender, ConsoleCancelEventArgs args)
    {
        Console.WriteLine("\nThe read operation has been interrupted.");

        Console.WriteLine("  Key pressed: {0}", args.SpecialKey);

        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


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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