C# Task 学习记录

        在 C# 中，Task是用于表示异步操作的核心类型之一，提供了一种简单、高效的方式来处理异步操作，使得开发者可以轻松地编写非阻塞的代码。下面是C# Task例子，包含取消、超时、延续任务、获取任务执行情况：

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

public class Program
{
    private static CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
    public static void Main(string[] args)
    {
        asyncStaticFunction();
        Console.Read();
    }

    public async static void asyncStaticFunction()
    {

        Task<string> task;
        string result = "被中断";
        //cancellationTokenSource.CancelAfter(10);//设置超时，会在10毫秒取消任务
        task = testTask("Hello world", cancellationTokenSource.Token);
        task.ContinueWith(t =>
        {
            Console.WriteLine(t.Status.ToString());
        }, TaskContinuationOptions.ExecuteSynchronously);//同步执行延续任务
        try
        {
            result = await task;
        }
        catch (OperationCanceledException ex)
        {
            Console.WriteLine("testTask发生错误：被取消了");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"testTask发生错误：{ex.Message}");
        }
        if (task.IsCompleted)//不管是出错还是取消，IsCompleted都会是true
        {
            Console.WriteLine("testTask完成了");
        }
        if (task.IsCanceled)
        {
            Console.WriteLine("testTask被取消了");
        }
        if (task.IsFaulted)
        {
            Console.WriteLine("testTask出错了");
        }
        Console.WriteLine($"testTask返回值:{result}");
    }

    public async static Task<string> testTask(string message, CancellationToken cancellationToken)//不需要返回值就直接Task类型
    {
        for (int time = 0; time < 10; time++)
        {
            cancellationToken.ThrowIfCancellationRequested();
            Console.WriteLine($"testTask{time}:{message}");
            await Task.Delay(100);
            if (time == 5 && false)//为true会结束任务，会进入asyncStaticFunction的catch (Exception ex) ， Console.WriteLine($"testTask返回值:{result}");输出被中断
            {
                throw new Exception("testTask错误");
            }
            if (time == 5 && true)//为true会结束任务，进入asyncStaticFunction的catch (OperationCanceledException ex)， Console.WriteLine($"testTask返回值:{result}");输出被中断
            {
                cancellationTokenSource.Cancel();
            }
        }
        return "testTask完成";
    }
}