class Program
{static void Main(string[] args){//启动outer task，然后在outer task里面启动inner taskvar outerTask = Task.Run(async () =>{//await 之前执行Console.WriteLine("Thread ID " + Thread.CurrentThread.ManagedThreadId.ToString() + " : Outer task began!");//启动inner taskvar innerTask = Task.Run(() =>{//inner task 的线程沉睡5秒Thread.Sleep(5000);});//输出outer task即将开始awaitConsole.WriteLine("Thread ID " + Thread.CurrentThread.ManagedThreadId.ToString() + " : Outer task will await!");await innerTask;//在outerTask的线程中await innerTask的Task线程//await 完成之后执行，从下面的输出可以看到，await之后的代码是使用一个新的线程来执行的，因为下面的Thread ID和await之前发生了变化Console.WriteLine("Thread ID " + Thread.CurrentThread.ManagedThreadId.ToString() + " : Outer task will be finished!");});Thread.Sleep(1000);//主线程沉睡1秒，之后outer task的线程肯定开始执行了Console.WriteLine($"Outer task status:{outerTask.Status.ToString()}");//检查outer task的状态，可以看到此时状态为WaitingForActivationThread.Sleep(6000);//沉睡6秒，之后outer task和inner task的线程肯定结束执行了，也就是说outerTask和innerTask应该都结束了Console.WriteLine($"Outer task status:{outerTask.Status.ToString()}");//再次检查outer task的状态，可以看此时状态为RanToCompletion
Console.WriteLine();Console.WriteLine();Console.WriteLine("Press key contiune...");Console.ReadKey();}
}

class Program
{//定义outer thread为Program类的静态变量，这样我们在其执行方法OuterThreadRun中也可以检查outer thread的状态static Thread outerThread;//这是outer thread的执行方法，其在outer thread里面启动inner taskstatic async void OuterThreadRun(){//await 之前执行Console.WriteLine("Thread ID " + Thread.CurrentThread.ManagedThreadId.ToString() + " : Outer thread began!");//显示在执行中的outer thread的状态，此时状态显示为Background，因为outer thread为后台线程，所以Background表示后台线程正在执行Console.WriteLine($"Thread ID { Thread.CurrentThread.ManagedThreadId.ToString() } : Outer thread status:{outerThread.ThreadState.ToString()}");//启动inner taskvar innerTask = Task.Run(() =>{//inner task 的线程沉睡5秒Thread.Sleep(5000);});//输出outer thread即将开始awaitConsole.WriteLine("Thread ID " + Thread.CurrentThread.ManagedThreadId.ToString() + " : Outer thread will await!");await innerTask;//在outer thread线程中await innerTask的Task线程//await 完成之后执行，从下面的输出可以看到，await之后的代码是使用一个新的线程来执行的，因为下面的Thread ID和await之前发生了变化Console.WriteLine("Thread ID " + Thread.CurrentThread.ManagedThreadId.ToString() + " : Outer thread will be finished!");}static void Main(string[] args){//初始化outer thread，绑定执行方法为OuterThreadRun，并设置IsBackground为true，即后台线程outerThread = new Thread(new ThreadStart(OuterThreadRun)){IsBackground = true};//开始执行outer thread
        outerThread.Start();Thread.Sleep(1000);//主线程沉睡1秒，之后outer thread线程肯定开始执行了Console.WriteLine($"Outer thread status:{outerThread.ThreadState.ToString()}");//检查outer thread的状态，可以看到此时状态为Stopped，因为现在outer thread正在await innerTask，这说明await中的线程状态是StoppedThread.Sleep(6000);//沉睡6秒，之后outer thread线程和inner task的线程肯定结束执行了，也就是说outerThread和innerTask应该都结束了Console.WriteLine($"Outer thread status:{outerThread.ThreadState.ToString()}");//再次检查outer thread的状态，可以看此时状态为Stopped，因为outerThread和innerTask都结束运行了
Console.WriteLine();Console.WriteLine();Console.WriteLine("Press key contiune...");Console.ReadKey();}
}