很多时候我们需要做一段延时处理，就直接Thread.Sleep(n)处理了，但实际上延时也可以用Task.Delay(n)，那二者之间有没有区别呢？

我们先来看一个案例：

using System;
using System.Threading;
using System.Threading.Tasks;namespace ConsoleApp22
{class Program{static void Main(string[] args){//Good writingTask.Run(async () =>{int delayTimeCount = 0;while (true){Console.WriteLine($"Delay第{++delayTimeCount}秒");await Task.Delay(1000);}});//Bad writingTask.Run(() =>{int sleepTimeCount = 0;while (true){Console.WriteLine($"Thread{++sleepTimeCount}秒");Thread.Sleep(1000);}});Console.ReadKey();}}
}

运行结果：

区别：

①.Thread.Sleep()是同步延迟，既然是同步的，自然会阻塞当前线程；Task.Delay()是异步延迟，则不会阻塞线程；
②.Thread.Sleep()不能中途取消，Task.Delay()可以，delay有四个重载方法，需要取消的话，可以调用Delay(int millisecondsDelay, CancellationToken cancellationToken)这个方法；

//// 摘要://     Creates a task that completes after a specified number of milliseconds.//// 参数://   millisecondsDelay://     The number of milliseconds to wait before completing the returned task, or -1//     to wait indefinitely.//// 返回结果://     A task that represents the time delay.//// 异常://   T:System.ArgumentOutOfRangeException://     The millisecondsDelay argument is less than -1.public static Task Delay(int millisecondsDelay);//// 摘要://     Creates a cancellable task that completes after a specified number of milliseconds.//// 参数://   millisecondsDelay://     The number of milliseconds to wait before completing the returned task, or -1//     to wait indefinitely.////   cancellationToken://     A cancellation token to observe while waiting for the task to complete.//// 返回结果://     A task that represents the time delay.//// 异常://   T:System.ArgumentOutOfRangeException://     The millisecondsDelay argument is less than -1.////   T:System.Threading.Tasks.TaskCanceledException://     The task has been canceled.////   T:System.ObjectDisposedException://     The provided cancellationToken has already been disposed.public static Task Delay(int millisecondsDelay, CancellationToken cancellationToken);//// 摘要://     Creates a task that completes after a specified time interval.//// 参数://   delay://     The time span to wait before completing the returned task, or TimeSpan.FromMilliseconds(-1)//     to wait indefinitely.//// 返回结果://     A task that represents the time delay.//// 异常://   T:System.ArgumentOutOfRangeException://     delay represents a negative time interval other than TimeSpan.FromMilliseconds(-1).//     -or- The delay argument's System.TimeSpan.TotalMilliseconds property is greater//     than System.Int32.MaxValue.public static Task Delay(TimeSpan delay);//// 摘要://     Creates a cancellable task that completes after a specified time interval.//// 参数://   delay://     The time span to wait before completing the returned task, or TimeSpan.FromMilliseconds(-1)//     to wait indefinitely.////   cancellationToken://     A cancellation token to observe while waiting for the task to complete.//// 返回结果://     A task that represents the time delay.//// 异常://   T:System.ArgumentOutOfRangeException://     delay represents a negative time interval other than TimeSpan.FromMilliseconds(-1).//     -or- The delay argument's System.TimeSpan.TotalMilliseconds property is greater//     than System.Int32.MaxValue.////   T:System.Threading.Tasks.TaskCanceledException://     The task has been canceled.////   T:System.ObjectDisposedException://     The provided cancellationToken has already been disposed.public static Task Delay(TimeSpan delay, CancellationToken cancellationToken);

③在异步代码中通常使用await关键字调用Task.Delay()，而不是Thread.Sleep()；