Console.CancelKeyPress Console.CancelKeyPress Console.CancelKeyPress Console.CancelKeyPress Event

Definizione

Si verifica quando il tasto di modifica Control (CTRL) e il tasto della console C (C) o il tasto INTERR vengono premuti contemporaneamente (CTRL+C o CTRL+INTERR).Occurs when the Control modifier key (Ctrl) and either the C console key (C) or the Break key are pressed simultaneously (Ctrl+C or Ctrl+Break).

public:
 static event ConsoleCancelEventHandler ^ CancelKeyPress;
public static event ConsoleCancelEventHandler CancelKeyPress;
member this.CancelKeyPress : ConsoleCancelEventHandler 
Public Shared Custom Event CancelKeyPress As ConsoleCancelEventHandler 

Esempi

Nell'esempio seguente viene illustrato come il CancelKeyPress l'evento viene utilizzato.The following example demonstrates how the CancelKeyPress event is used. Quando si preme Ctrl + C, viene interrotta l'operazione di lettura e la myHandler viene richiamato il gestore di evento.When you press Ctrl+C, the read operation is interrupted and the myHandler event handler is invoked. Al momento dell'accesso al gestore eventi, il ConsoleCancelEventArgs.Cancel è di proprietà false, il che significa che il processo corrente verrà interrotto quando termina il gestore dell'evento.Upon entry to the event handler, the ConsoleCancelEventArgs.Cancel property is false, which means that the current process will terminate when the event handler terminates. Tuttavia, il gestore dell'evento imposta il ConsoleCancelEventArgs.Cancel proprietà true, che significa che il processo non verrà interrotto e riprenderà l'operazione di lettura.However, the event handler sets the ConsoleCancelEventArgs.Cancel property to true, which means that the process will not terminate and the read operation will resume.

using namespace System;

void OnCancelKeyPressed(Object^ sender, 
    ConsoleCancelEventArgs^ args)
{
    Console::WriteLine("{0}The read operation has been interrupted.",
        Environment::NewLine);

    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...{0}",
        Environment::NewLine);
}

int main()
{       
    // Clear the screen.
    Console::Clear();

    // Establish an event handler to process key press events.
    Console::CancelKeyPress += 
        gcnew ConsoleCancelEventHandler(OnCancelKeyPressed);

    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.
        ConsoleKeyInfo^ keyInfo = Console::ReadKey(true);

        // Announce the name of the key that was pressed .
        Console::WriteLine("  Key pressed: {0}{1}", keyInfo->Key, 
            Environment::NewLine);

        // Exit if the user pressed the 'X' key.
        if (keyInfo->Key == ConsoleKey::X)
        {
            break;
        }
    }
}
// The example displays output similar to the following:
//    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
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
Class Sample
    Public Shared Sub Main() 
        Dim cki As ConsoleKeyInfo
        
        Console.Clear()
        
        ' Establish an event handler to process key press events.
        AddHandler Console.CancelKeyPress, AddressOf 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}" & vbCrLf, cki.Key)
            
            ' Exit if the user pressed the 'X' key.
            If cki.Key = ConsoleKey.X Then Exit While
        End While
    End Sub

    Protected Shared Sub myHandler(ByVal sender As Object, _
                                   ByVal args As ConsoleCancelEventArgs) 
        Console.WriteLine(vbCrLf & "The 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..." & vbCrLf)
    End Sub
End Class
' The example diplays output similar to the following:
'    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

Commenti

Questo evento viene utilizzato in combinazione con System.ConsoleCancelEventHandler e System.ConsoleCancelEventArgs.This event is used in conjunction with System.ConsoleCancelEventHandler and System.ConsoleCancelEventArgs. Il CancelKeyPress evento consente a un'applicazione console per rilevare il segnale Ctrl + C in modo che il gestore eventi può decidere se continuare l'esecuzione o terminare.The CancelKeyPress event enables a console application to intercept the Ctrl+C signal so the event handler can decide whether to continue executing or terminate. Per ulteriori informazioni sulla gestione degli eventi, consultare gestione e generazione di eventi.For more information about handling events, see Handling and Raising Events.

Quando l'utente preme Ctrl + C o Ctrl + INTERR, le CancelKeyPress evento viene generato e l'applicazione ConsoleCancelEventHandler viene eseguito il gestore eventi.When the user presses either Ctrl+C or Ctrl+Break, the CancelKeyPress event is fired and the application's ConsoleCancelEventHandler event handler is executed. Il gestore dell'evento viene passato un ConsoleCancelEventArgs oggetto che ha due proprietà utile:The event handler is passed a ConsoleCancelEventArgs object that has two useful properties:

  • SpecialKey, che consente di determinare se il gestore di è stato richiamato come risultato dell'utente se si preme Ctrl + C (il valore della proprietà ConsoleSpecialKey.ControlC) o Ctrl + INTERR (il valore della proprietà è ConsoleSpecialKey.ControlBreak).SpecialKey, which allows you to determine whether the handler was invoked as a result of the user pressing Ctrl+C (the property value is ConsoleSpecialKey.ControlC) or Ctrl+Break (the property value is ConsoleSpecialKey.ControlBreak).

  • Cancel, che consente di determinare la modalità per l'applicazione deve rispondere all'utente premendo Ctrl + C o Ctrl + INTERR.Cancel, which allows you to determine how to your application should respond to the user pressing Ctrl+C or Ctrl+Break. Per impostazione predefinita, il Cancel è di proprietà false, che causa l'esecuzione di terminare quando viene chiuso il gestore dell'evento del programma.By default, the Cancel property is false, which causes program execution to terminate when the event handler exits. Modifica la proprietà su true specifica che l'applicazione deve continuare a eseguire.Changing its property to true specifies that the application should continue to execute.

Suggerimento

Se l'applicazione presenta requisiti semplici, è possibile usare il TreatControlCAsInput proprietà anziché questo evento.If your application has simple requirements, you can use the TreatControlCAsInput property instead of this event. Impostando questa proprietà su false, è possibile assicurarsi che l'applicazione sempre viene chiuso se l'utente preme Ctrl + C.By setting this property to false, you can ensure that your application always exits if the user presses Ctrl+C. Impostandola su true, è possibile assicurarsi che se si preme Ctrl + C non terminare l'applicazione.By setting it to true, you can ensure that pressing Ctrl+C will not terminate the application.

Il gestore eventi per questo evento viene eseguito in un pool di thread.The event handler for this event is executed on a thread pool thread.

Sicurezza

UIPermission
Per modificare le finestre di primo livello sicure e secondarie.for modifying safe top-level windows and subwindows. Enumerazione associata: SafeTopLevelWindowsAssociated enumeration: SafeTopLevelWindows

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