1、C#异步模式分类
基于任务的异步模式（TAP）
基于事件的异步模式（EAP）和异步编程模型模式（APM）
2、基于任务的异步模式（TAP）
基于任务的异步模式（TAP）用单个方法表示异步操作的开始和完成。
3、基本示例

static void Main(string[] args){var task = DoWork();Console.ReadKey();}public static Task DoWork(){for (int i = 0; i < 10; i++){Console.WriteLine(i);Task.Delay(1000);}return Task.CompletedTask;}}

4、任务终止示例

static void Main(string[] args){CancellationTokenSource cts = new CancellationTokenSource();CancellationToken token = cts.Token;var task = DoWork(token);Thread.Sleep(100);cts.Cancel();Console.WriteLine("cancel..");Console.ReadKey();}public static Task DoWork(CancellationToken cancellationToken){while (!cancellationToken.IsCancellationRequested){Console.WriteLine("wait..");Thread.Sleep(1000);return Task.CompletedTask;}return Task.FromCanceled(cancellationToken);}}

5、进度显示示例

static void Main(string[] args){var progress = new Progress<double>(p =>{Console.WriteLine($"进度：{p}%");});var task = DoWork(progress);Console.ReadKey();}public static async Task DoWork(IProgress<double> progress){for(int i = 0; i <= 1000; i++){await Task.Delay(10);if(i%100 == 0){double d = i/10.0;progress?.Report(d);}}}}