这时候编译器会报一个错误 :CS1061 “Task”未包含“GetAwaiter”的定义,并且找不到可接受第一个“Task”类型参数的可访问扩展方法“GetAwaiter”(是否缺少 using 指令或程序集引用?)
扩展代码:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
using System; using System.Collections.Generic; using System.Linq; using System.Runtime.CompilerServices; using System.Security; using System.Text; using System.Threading.Tasks; namespace System.Threading.Tasks { internal static class TaskEx { public static TaskAwaiter GetAwaiter(this Task task) { return new TaskAwaiter(task); } public static TaskAwaiter<T> GetAwaiter<T>(this Task<T> task) { return new TaskAwaiter<T>(task); } public static Task Run(Action action) { return Task.Factory.StartNew(action); } } internal struct TaskAwaiter : INotifyCompletion { readonly Task task; internal TaskAwaiter(Task task) { this.task = task; } internal static TaskScheduler TaskScheduler { get { if (SynchronizationContext.Current == null) return TaskScheduler.Default; else return TaskScheduler.FromCurrentSynchronizationContext(); } } public bool IsCompleted { get { return task.IsCompleted; } } public void OnCompleted(Action continuation) { this.task.ContinueWith( delegate (Task task) { //Console.WriteLine("状态机回调函数信息:"+Thread.CurrentThread.ManagedThreadId); //Console.WriteLine("\t名称:"+continuation.Method.Name); //Console.WriteLine("\t所属类型:" + continuation.Method.DeclaringType.ToString()); continuation(); }, TaskAwaiter.TaskScheduler); } public void GetResult() { try { task.Wait(); } catch (AggregateException ex) { throw ex.InnerExceptions[0]; } } } internal struct TaskAwaiter<T> : INotifyCompletion { readonly Task<T> task; internal TaskAwaiter(Task<T> task) { this.task = task; } public bool IsCompleted { get { return task.IsCompleted; } } public void OnCompleted(Action continuation) { this.task.ContinueWith( delegate (Task<T> task) { continuation(); }, TaskAwaiter.TaskScheduler); } public T GetResult() { try { return task.Result; } catch (AggregateException ex) { throw ex.InnerExceptions[0]; } } } } namespace System.Runtime.CompilerServices { internal interface INotifyCompletion { void OnCompleted(Action continuation); } internal interface ICriticalNotifyCompletion : INotifyCompletion { [SecurityCritical] void UnsafeOnCompleted(Action continuation); } internal interface IAsyncStateMachine { void MoveNext(); void SetStateMachine(IAsyncStateMachine stateMachine); } internal struct AsyncVoidMethodBuilder { public static AsyncVoidMethodBuilder Create() { return new AsyncVoidMethodBuilder(); } public void SetException(Exception exception) { throw exception; } public void SetResult() { } public void SetStateMachine(IAsyncStateMachine stateMachine) { // Should not get called as we don't implement the optimization that this method is used for. throw new NotImplementedException(); } public void Start<TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine { stateMachine.MoveNext(); } public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } } internal struct AsyncTaskMethodBuilder { TaskCompletionSource<object> tcs; public Task Task { get { return tcs.Task; } } public static AsyncTaskMethodBuilder Create() { AsyncTaskMethodBuilder b; b.tcs = new TaskCompletionSource<object>(); return b; } public void Start<TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine { stateMachine.MoveNext(); } public void SetStateMachine(IAsyncStateMachine stateMachine) { // Should not get called as we don't implement the optimization that this method is used for. throw new NotImplementedException(); } public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void SetResult() { tcs.SetResult(null); } public void SetException(Exception exception) { tcs.SetException(exception); } } internal struct AsyncTaskMethodBuilder<T> { TaskCompletionSource<T> tcs; public Task<T> Task { get { return tcs.Task; } } public static AsyncTaskMethodBuilder<T> Create() { AsyncTaskMethodBuilder<T> b; b.tcs = new TaskCompletionSource<T>(); return b; } public void Start<TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine { stateMachine.MoveNext(); } public void SetStateMachine(IAsyncStateMachine stateMachine) { // Should not get called as we don't implement the optimization that this method is used for. throw new NotImplementedException(); } public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine { AwaitOnCompleted(ref awaiter, ref stateMachine); } public void SetResult(T result) { tcs.SetResult(result); } public void SetException(Exception exception) { tcs.SetException(exception); } } }View Code
标签:task,4.0,stateMachine,void,Task,TStateMachine,async,net,public From: https://www.cnblogs.com/cyj0923/p/16876253.html