c# - 在 Visual Studio 2019 调试器中运行时，为什么控制台应用程序在最后一条语句后不退出？

Question

我正在寻找一种异步友好的方式来等待 ctrl+c 退出 C# 控制台应用程序。如果我直接运行编译的二进制文件，下面的代码有效。但是，如果我在调试器中运行它，输入 ctrl+c，然后单步执行，我会碰到程序的右大括号，但它不会退出。如果我注释掉等待，应用程序会正常完成，所以我认为这不是 VS 设置问题。

using System;
using System.Threading;
using System.Threading.Tasks;

public class Program
{
    public static async Task Main()
    {
        Console.WriteLine("Hello World");
        await UntilCancelled().ConfigureAwait(true);
        Console.WriteLine("Goodbye Cruel World");
    }

    /// <summary>
    /// Waits until Ctrl+c or Ctrl+Break is entered into the console
    /// </summary>
    /// <param name="cancellationToken">A passed in cancellation token can also cause the await to complete</param>
    /// <returns>True when cancelled</returns>
    public static Task UntilCancelled(CancellationToken cancellationToken = default)
    {
        var cts = new CancellationTokenSource();
        //link tokens if caller wants to have ability to cancel for other conditions
        if (default != cancellationToken)
            cts = CancellationTokenSource.CreateLinkedTokenSource(cts.Token, cancellationToken);

        //Attach cancellation to event for exiting the console
        Console.CancelKeyPress += (sender, cpe) => cts.Cancel();

        var tcs = new TaskCompletionSource<bool>();
        cts.Token.Register(s => ((TaskCompletionSource<bool>)s).SetResult(true), tcs);
        return tcs.Task;
    }
}

Answer 1

尝试这个:

public static Task UntilCancelled(CancellationToken cancellationToken = default)
{
    var tcs = new TaskCompletionSource<bool>();
    cancellationToken.Register(() => tcs.TrySetResult(true));
    Console.CancelKeyPress += (sender, cpe) =>
    {
        // this will prevent windows from interfering with the shutdown process
        cpe.Cancel = true; 
        tcs.TrySetResult(true);
    };

    return tcs.Task;
}

我用这个测试了它:

var cts = new CancellationTokenSource();
Console.WriteLine("Started");
Task.Run(async () =>
{
    await Task.Delay(5000);
    cts.Cancel(false);
}).GetAwaiter();
await Test.UntilCancelled(cts.Token);
Console.WriteLine("Canceled");