/// <summary>
/// C# 5.0
/// .net framework4.5
/// CLR4.0
/// 引入了async 和 await。这两个关键字可以让你更方便的写出异步代码。以前是委托 BeginInvoke （）
/// async/await是依附于Task的异步，
/// 只有async方法认为是同步的，只是返回结果类型是
/// await一定存在于async方法里面 只有async没有await的话是同步方法
/// 返回的结果是Task<T>，其中T为最终结果
/// await关键字只能放在Task前面
---------------------------------------------------------------
/// <summary>
/// 只有async没有await，会有个warn
/// 跟普通方法没有区别
/// </summary>
private static async void NoReturnNoAwait()
{
//主线程执行
Console.WriteLine("NoReturnNoAwait Sleep before Task,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
Task task = Task.Run(() =>//启动新线程完成任务
{
Console.WriteLine("NoReturnNoAwait Sleep before,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
Thread.Sleep(3000);
Console.WriteLine("NoReturnNoAwait Sleep after,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
});
//主线程执行
Console.WriteLine("NoReturnNoAwait Sleep after Task,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
}
-------------------------------------------------------------------------------------------
/// <summary>
/// async/await
/// await 要放在task前面
/// 不推荐void返回值，使用Task来代替
/// Task和Task<T>能够使用await, Task.WhenAny, Task.WhenAll等方式组合使用。Async Void 不行
/// </summary>
private static async void NoReturn()
{
//主线程执行
Console.WriteLine("NoReturn Sleep before await,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
TaskFactory taskFactory = new TaskFactory();
Task task = taskFactory.StartNew(() =>
{
Console.WriteLine("NoReturn Sleep before,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
Thread.Sleep(3000);
Console.WriteLine("NoReturn Sleep after,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
});
await task;
//子线程执行 其实是封装成委托，在task之后成为回调（编译器功能 状态机实现）
Console.WriteLine("NoReturn Sleep after await,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);//这个不由主线程执行
}
/// <summary>
/// 无返回值 async Task == async void
/// Task和Task<T>能够使用await, Task.WhenAny, Task.WhenAll等方式组合使用。Async Void 不行
/// </summary>
/// <returns></returns>
private static async Task NoReturnTask()
{
//这里还是主线程的id
Console.WriteLine("NoReturnTask Sleep before await,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
Task task = Task.Run(() =>
{
Console.WriteLine("NoReturnTask Sleep before,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
Thread.Sleep(3000);
Console.WriteLine("NoReturnTask Sleep after,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
});
await task;
Console.WriteLine("NoReturnTask Sleep after await,ThreadId={0}", Thread.CurrentThread.ManagedThreadId);
//return new TaskFactory().StartNew(() => { }); 不能return
}
/// <summary>
/// 带返回值的Task
/// 要使用返回值就一定要等子线程计算完毕
/// </summary>
/// <returns>async 就只返回long</returns>
private static async Task<long> SumAsync()
{
Console.WriteLine("SumAsync {1} start ManagedThreadId={0}", Thread.CurrentThread.ManagedThreadId, 111);
long result = 0;
await Task.Run(() =>
{
for (int k = 0; k < 10; k++)
{
Console.WriteLine("SumAsync {1} await Task.Run ManagedThreadId={0}", Thread.CurrentThread.ManagedThreadId, k);
System.Threading.Thread.Sleep(1000);
}
for (long i = 0; i < 999999999; i++)
{
result += i;
}
});
Console.WriteLine("SumAsync {1} end ManagedThreadId={0}", Thread.CurrentThread.ManagedThreadId, 111);
return result;
}