Console.CancelKeyPress 事件

定義

命名空間:

System

組件:

netstandard.dll, System.Console.dll

來源:

Console.cs

當 Control 修飾鍵（Ctrl）與 C 主控台鍵（C）或 Break 鍵同時按下（Ctrl+C 或 Ctrl+Break）時會發生。

public:
 static event ConsoleCancelEventHandler ^ CancelKeyPress;

[System.Runtime.Versioning.UnsupportedOSPlatform("android")]
[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
public static event ConsoleCancelEventHandler? CancelKeyPress;

[<System.Runtime.Versioning.UnsupportedOSPlatform("android")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
member this.CancelKeyPress : ConsoleCancelEventHandler 

Public Shared Custom Event CancelKeyPress As ConsoleCancelEventHandler 

事件類型

ConsoleCancelEventHandler

屬性

UnsupportedOSPlatformAttribute

範例

以下範例說明該事件的使用方式 CancelKeyPress 。 按下 Ctrl+C 時，讀取操作會中斷並 myHandler 呼叫事件處理程序。 進入事件處理器時， ConsoleCancelEventArgs.Cancel 屬性為 false，表示當前程序在事件處理程序終止時也會終止。 然而，事件處理器將屬性設 ConsoleCancelEventArgs.Cancel 為 true，表示程序不會終止，讀取操作會繼續。

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: {cki.Key}\n");

            // 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: {args.SpecialKey}");

        Console.WriteLine($"  Cancel property: {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: {args.Cancel}");
        Console.WriteLine("The read operation will resume...\n");
    }
}
// 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

open System

let myHandler sender (args: ConsoleCancelEventArgs) =
    printfn "\nThe read operation has been interrupted."

    printfn $"  Key pressed: {args.SpecialKey}"

    printfn $"  Cancel property: {args.Cancel}"

    // Set the Cancel property to true to prevent the process from terminating.
    printfn "Setting the Cancel property to true..."
    args.Cancel <- true

    // Announce the new value of the Cancel property.
    printfn $"  Cancel property: {args.Cancel}"
    printfn "The read operation will resume...\n"

// Establish an event handler to process key press events.
Console.CancelKeyPress.AddHandler(ConsoleCancelEventHandler myHandler)

let mutable quit = false
while not quit do
    printf "Press any key, or 'X' to quit, or "
    printfn "CTRL+C to interrupt the read operation:"

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

    // Announce the name of the key that was pressed .
    printfn $"  Key pressed: {cki.Key}\n"

    // Exit if the user pressed the 'X' key.
    if cki.Key = ConsoleKey.X then
        quit <- true

// 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

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: {cki.Key}{vbCrLf}")
            
            ' 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: {args.SpecialKey}")
        
        Console.WriteLine($"  Cancel property: {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($"  Cancel property: {args.Cancel}")
        Console.WriteLine($"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

備註

此事件與 及 System.ConsoleCancelEventArgs結合使用System.ConsoleCancelEventHandler。 事件 CancelKeyPress 讓主控台應用程式能攔截 Ctrl+C 訊號，讓事件處理器決定是繼續執行還是終止。 如需處理事件的詳細資訊，請參閱 處理和引發事件。

當使用者按下 Ctrl+C 或 Ctrl+Break 時， CancelKeyPress 事件會觸發並執行應用程式的 ConsoleCancelEventHandler 事件處理程序。 事件處理器會被傳遞一個 ConsoleCancelEventArgs 具有兩個實用特性的物件：

• SpecialKey，這讓你能判斷處理器是因為使用者按了 Ctrl+C（屬性值為 ConsoleSpecialKey.ControlC）還是 Ctrl+Break（屬性值為 ConsoleSpecialKey.ControlBreak）而被呼叫。

• Cancel，這讓應用程式能判斷使用者按下 Ctrl+C 或 Ctrl+Break 時應如何回應。 預設 Cancel 屬性為 false，當事件處理程序退出時，程式執行會終止。 將屬性更改為 指定 true 應用程式應繼續執行。

小提示

如果你的申請條件簡單，你可以用該 TreatControlCAsInput 房產代替這個活動。 將此屬性設為 false，你可以確保使用者按下 Ctrl+C 時應用程式會自動退出。 將它設為 true，你可以確保按 Ctrl+C 不會終止應用程式。

此事件的事件處理程序是在執行緒池執行緒上執行。

另請參閱

• ConsoleCancelEventArgs
• ConsoleCancelEventHandler
• TreatControlCAsInput