在C#中取消异步和等待方法

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

public class Program
{
    public static async Task Main()
    {
        CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
        CancellationToken cancellationToken = cancellationTokenSource.Token;

        Task<int> task = DoAsyncOperation(cancellationToken);

        // 模拟取消操作
        cancellationTokenSource.CancelAfter(TimeSpan.FromSeconds(2));

        try
        {
            int result = await task;
            Console.WriteLine($"异步操作的结果为：{result}");
        }
        catch (OperationCanceledException)
        {
            Console.WriteLine("异步操作已被取消");
        }
    }

    public static async Task<int> DoAsyncOperation(CancellationToken cancellationToken)
    {
        await Task.Delay(TimeSpan.FromSeconds(5), cancellationToken);

        // 在异步操作中检查是否需要取消操作
        if (cancellationToken.IsCancellationRequested)
        {
            cancellationToken.ThrowIfCancellationRequested();
        }

        return 42;
    }
}