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";
}
}