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lang: ja-jp
breaks: true
---
# C＃コンソールアプリで `Ctrl+C`（SIGINT）をトラップする方法 2021-07-22

> Console.CancelKeyPress Event
> https://docs.microsoft.com/en-us/dotnet/api/system.console.cancelkeypress?redirectedfrom=MSDN&view=net-5.0

using (CancellationTokenSource cancellationTokenSource = new())
{
    Console.CancelKeyPress += (o, a) =>
        {
            if (a.SpecialKey == ConsoleSpecialKey.ControlC)
            {
                cancellationTokenSource.Cancel();
            };
            Console.WriteLine($"{a.Cancel} {a.SpecialKey}");
        };
・・・
}

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

###### tags: `C#` `コンソール` `Ctrl+C` `SIGINT` `Console` `キャンセル` `Cancel` `CancellationTokenSource`