Task<TResult>.ContinueWith 方法

定义

创建一个延续任务,该任务在另一个任务完成时执行。

重载

名称 说明
ContinueWith(Action<Task<TResult>,Object>, Object, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith(Action<Task<TResult>>, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建一个根据中指定的 continuationOptions条件执行的延续。

ContinueWith(Action<Task<TResult>,Object>, Object, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith(Action<Task<TResult>,Object>, Object, CancellationToken)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith(Action<Task<TResult>,Object>, Object, TaskContinuationOptions)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith(Action<Task<TResult>>, TaskContinuationOptions)

创建一个根据中指定的 continuationOptions条件执行的延续。

ContinueWith(Action<Task<TResult>>, CancellationToken)

创建在目标 Task<TResult> 完成时异步执行的可取消延续。

ContinueWith(Action<Task<TResult>,Object>, Object)

创建一个延续,该延续是传递的状态信息,并在目标 Task<TResult> 完成时执行。

ContinueWith(Action<Task<TResult>>)

创建在目标任务完成时异步执行的延续。

ContinueWith(Action<Task<TResult>>, TaskScheduler)

创建在目标 Task<TResult> 完成时异步执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建一个根据中指定的 continuationOptions条件执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, TaskContinuationOptions)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, CancellationToken)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, TaskContinuationOptions)

创建一个根据中指定的 continuationOptions条件执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, CancellationToken)

创建在目标 Task<TResult> 完成时异步执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object)

创建在目标 Task<TResult> 完成时执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>)

创建在目标 Task<TResult> 完成时异步执行的延续。

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, TaskScheduler)

创建在目标 Task<TResult> 完成时异步执行的延续。

ContinueWith(Action<Task<TResult>,Object>, Object, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>,object> continuationAction, object state, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>, obj> * obj * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult), Object), state As Object, cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task

参数

continuationAction
Action<Task<TResult>,Object>

完成时 Task<TResult> 要运行的操作。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续操作要使用的数据。

cancellationToken
CancellationToken

CancellationToken 分配给新的延续任务。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

新的延续 Task

例外

参数 schedulernull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

已释放所提供的 CancellationToken 内容。

注解

在当前任务完成之前,不会计划返回 Task 的执行。 如果未满足通过 continuationOptions 参数指定的条件,将取消延续任务,而不是计划任务。

另请参阅

适用于

ContinueWith(Action<Task<TResult>>, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建一个根据中指定的 continuationOptions条件执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^> ^ continuationAction, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>> continuationAction, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>> * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult)), cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task

参数

continuationAction
Action<Task<TResult>>

要根据中指定的 continuationOptions条件运行的操作。 运行时,将委托作为参数传递已完成的任务。

cancellationToken
CancellationToken

CancellationToken 分配给新的延续任务。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

新的延续 Task

例外

Task<TResult>已处置。

-或-

CancellationTokenSource已释放创建的cancellationToken项。

参数 continuationActionnull.

-或-

参数 schedulernull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

注解

在当前任务完成之前,不会计划返回 Task 的执行。 如果未满足通过 continuationOptions 参数指定的条件,将取消延续任务,而不是计划任务。 有关详细信息,请参阅使用延续任务链接任务

另请参阅

适用于

ContinueWith(Action<Task<TResult>,Object>, Object, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>,object> continuationAction, object state, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>, obj> * obj * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult), Object), state As Object, scheduler As TaskScheduler) As Task

参数

continuationAction
Action<Task<TResult>,Object>

完成时 Task<TResult> 要运行的操作。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续操作要使用的数据。

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

新的延续 Task

例外

参数 schedulernull.

注解

在当前任务完成之前,将不安排返回 Task 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith(Action<Task<TResult>,Object>, Object, CancellationToken)

创建在目标 Task<TResult> 完成时执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::CancellationToken cancellationToken);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>,object> continuationAction, object state, System.Threading.CancellationToken cancellationToken);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>, obj> * obj * System.Threading.CancellationToken -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult), Object), state As Object, cancellationToken As CancellationToken) As Task

参数

continuationAction
Action<Task<TResult>,Object>

完成时 Task<TResult> 要运行的操作。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续操作要使用的数据。

cancellationToken
CancellationToken

CancellationToken 分配给新的延续任务。

返回

新的延续 Task

例外

参数 continuationActionnull.

已释放所提供的 CancellationToken 内容。

注解

在当前任务完成之前,将不安排返回 Task 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith(Action<Task<TResult>,Object>, Object, TaskContinuationOptions)

创建在目标 Task<TResult> 完成时执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::Tasks::TaskContinuationOptions continuationOptions);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>,object> continuationAction, object state, System.Threading.Tasks.TaskContinuationOptions continuationOptions);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>, obj> * obj * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult), Object), state As Object, continuationOptions As TaskContinuationOptions) As Task

参数

continuationAction
Action<Task<TResult>,Object>

完成时 Task<TResult> 要运行的操作。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续操作要使用的数据。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

返回

新的延续 Task

例外

参数 continuationActionnull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

注解

在当前任务完成之前,不会计划返回 Task 的执行。 如果未满足通过 continuationOptions 参数指定的延续条件,将取消延续任务,而不是计划任务。

另请参阅

适用于

ContinueWith(Action<Task<TResult>>, TaskContinuationOptions)

创建一个根据中指定的 continuationOptions条件执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^> ^ continuationAction, System::Threading::Tasks::TaskContinuationOptions continuationOptions);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>> continuationAction, System.Threading.Tasks.TaskContinuationOptions continuationOptions);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>> * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult)), continuationOptions As TaskContinuationOptions) As Task

参数

continuationAction
Action<Task<TResult>>

根据中指定的 continuationOptions条件执行的操作。 运行时,将委托作为参数传递已完成的任务。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

返回

新的延续 Task

例外

参数 continuationActionnull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

注解

在当前任务完成之前,不会计划返回 Task 的执行。 如果未满足通过 continuationOptions 参数指定的延续条件,将取消延续任务,而不是计划任务。

有关详细信息,请参阅使用延续任务链接任务

另请参阅

适用于

ContinueWith(Action<Task<TResult>>, CancellationToken)

创建在目标 Task<TResult> 完成时异步执行的可取消延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^> ^ continuationAction, System::Threading::CancellationToken cancellationToken);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>> continuationAction, System.Threading.CancellationToken cancellationToken);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>> * System.Threading.CancellationToken -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult)), cancellationToken As CancellationToken) As Task

参数

continuationAction
Action<Task<TResult>>

完成时 Task<TResult> 要运行的操作。 运行时,将委托作为参数传递已完成的任务。

cancellationToken
CancellationToken

传递给新延续任务的取消标记。

返回

新的延续任务。

例外

Task<TResult>已处置。

-或-

CancellationTokenSource已释放创建的cancellationToken项。

参数 continuationActionnull.

示例

以下示例创建使用 Eratosthenes 的 Sieve 计算 1 与用户输入的值之间的质数的先行任务。 数组用于保存有关质数的信息。 数组索引表示数字,元素的值指示该数字是复合的(其值为 true)还是质数(其值为 false)。 然后,此任务将传递给延续任务,该任务负责从整数数组中提取质数并显示它们。

取消令牌将同时传递给前面的任务和延续任务。 对象 System.Timers.Timer 用于定义超时值 100 毫秒。 如果触发事件, CancellationTokenSource.Cancel 将调用该方法,并使用取消令牌请求取消任务。

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Timers = System.Timers;

public class Example
{
   static CancellationTokenSource ts;
   
   public static void Main(string[] args)
   {
      int upperBound = args.Length >= 1 ? Int32.Parse(args[0]) : 200;
      ts = new CancellationTokenSource();
      CancellationToken token = ts.Token;
      Timers.Timer timer = new Timers.Timer(3000);
      timer.Elapsed += TimedOutEvent;
      timer.AutoReset = false;
      timer.Enabled = true;

      var t1 = Task.Run(() => { // True = composite.
                                // False = prime.
                                bool[] values = new bool[upperBound + 1];
                                for (int ctr = 2; ctr <= (int) Math.Sqrt(upperBound); ctr++) {
                                   if (!values[ctr] ) {
                                      for (int product = ctr * ctr; product <= upperBound;
                                                                    product = product + ctr)
                                         values[product] = true;
                                   }
                                   token.ThrowIfCancellationRequested();
                                }
                                return values; }, token);

      var t2 = t1.ContinueWith( (antecedent) => { // Create a list of prime numbers.
                                                  var  primes = new List<int>();
                                                  token.ThrowIfCancellationRequested();
                                                  bool[] numbers = antecedent.Result;
                                                  string output = String.Empty;

                                                  for (int ctr = 1; ctr <= numbers.GetUpperBound(0); ctr++)
                                                     if (!numbers[ctr] )
                                                        primes.Add(ctr);

                                                  // Create the output string.
                                                  for (int ctr = 0; ctr < primes.Count; ctr++) {
                                                     token.ThrowIfCancellationRequested();
                                                     output += primes[ctr].ToString("N0");
                                                     if (ctr < primes.Count - 1)
                                                        output += ",  ";
                                                     if ((ctr + 1) % 8 == 0)
                                                        output += Environment.NewLine;
                                                  }
                                                  //Display the result.
                                                  Console.WriteLine("Prime numbers from 1 to {0}:\n",
                                                                    upperBound);
                                                  Console.WriteLine(output);
                                                }, token);
      try {
         t2.Wait();
      }
      catch (AggregateException ae) {
         foreach (var e in ae.InnerExceptions) {
            if (e.GetType() == typeof(TaskCanceledException))
               Console.WriteLine("The operation was cancelled.");
            else
               Console.WriteLine("ELSE: {0}: {1}", e.GetType().Name, e.Message);
         }
      }
      finally {
         ts.Dispose();
      }
   }

   private static void TimedOutEvent(Object source, Timers.ElapsedEventArgs e)
   {
      ts.Cancel();
   }
}
// If cancellation is not requested, the example displays output like the following:
//       Prime numbers from 1 to 400:
//
//       1,  2,  3,  5,  7,  11,  13,  17,
//       19,  23,  29,  31,  37,  41,  43,  47,
//       53,  59,  61,  67,  71,  73,  79,  83,
//       89,  97,  101,  103,  107,  109,  113,  127,
//       131,  137,  139,  149,  151,  157,  163,  167,
//       173,  179,  181,  191,  193,  197,  199,  211,
//       223,  227,  229,  233,  239,  241,  251,  257,
//       263,  269,  271,  277,  281,  283,  293,  307,
//       311,  313,  317,  331,  337,  347,  349,  353,
//       359,  367,  373,  379,  383,  389,  397,  401
// If cancellation is requested, the example displays output like the following:
//       The operation was cancelled.
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks
Imports Timers = System.Timers

Module Example
   Dim ts As CancellationTokenSource

   Public Sub Main(args() As String)
      Dim upperBound As Integer = If(args.Length >= 1, CInt(args(0)), 200)
      ts = New CancellationTokenSource()
      Dim token As CancellationToken = ts.Token
      Dim timer As New Timers.Timer(100)
      AddHandler timer.Elapsed, AddressOf TimedOutEvent
      timer.AutoReset = False
      timer.Enabled = True

      Dim t1 = Task.Run(Function()
                          ' True = composite.
                          ' False = prime.
                          Dim values(upperBound) As Boolean
                          For ctr = 2 To CInt(Math.Sqrt(upperBound))
                             If values(ctr) = False Then
                                For product = ctr * ctr To upperBound Step ctr
                                   values(product) = True
                                Next
                             End If
                             token.ThrowIfCancellationRequested()
                          Next
                          Return values
                       End Function, token)

      Dim t2 = t1.ContinueWith(Sub(antecedent)
                                  ' Create a list of prime numbers.
                                  Dim primes As New List(Of Integer)()
                                  token.ThrowIfCancellationRequested()
                                  Dim numbers As Boolean() = antecedent.Result
                                  Dim output As String = String.Empty
                                  
                                  For ctr As Integer = 1 To numbers.GetUpperBound(0)
                                     If numbers(ctr) = False Then primes.Add(ctr)
                                  Next

                                  ' Create the output string.
                                  For ctr As Integer = 0 To primes.Count - 1
                                     token.ThrowIfCancellationRequested()
                                     output += primes(ctr).ToString("N0")
                                     If ctr < primes.Count - 1 Then output += ",  "
                                     If (ctr + 1) Mod 8 = 0 Then output += vbCrLf
                                  Next
                                  'Display the result.
                                  Console.WriteLine("Prime numbers from 1 to {0}:{1}",
                                                    upperBound, vbCrLf)
                                  Console.WriteLine(output)
                               End Sub, token)
      Try
         t2.Wait()
      Catch ae As AggregateException
         For Each e In ae.InnerExceptions
            If e.GetType Is GetType(TaskCanceledException) Then
               Console.WriteLine("The operation was cancelled.")
            Else
               Console.WriteLine("{0}: {1}", e.GetType().Name, e.Message)
            End If
         Next
      Finally
         ts.Dispose()
      End Try
   End Sub
   
   Private Sub TimedOutEvent(source As Object, e As Timers.ElapsedEventArgs)
      ts.Cancel()
   End Sub
End Module
' If cancellation is not requested, the example displays output like the following:
'       Prime numbers from 1 to 400:
'
'       1,  2,  3,  5,  7,  11,  13,  17,
'       19,  23,  29,  31,  37,  41,  43,  47,
'       53,  59,  61,  67,  71,  73,  79,  83,
'       89,  97,  101,  103,  107,  109,  113,  127,
'       131,  137,  139,  149,  151,  157,  163,  167,
'       173,  179,  181,  191,  193,  197,  199,  211,
'       223,  227,  229,  233,  239,  241,  251,  257,
'       263,  269,  271,  277,  281,  283,  293,  307,
'       311,  313,  317,  331,  337,  347,  349,  353,
'       359,  367,  373,  379,  383,  389,  397,  401
' If cancellation is requested, the example displays output like the following:
'       The operation was cancelled.

通常,提供一个值约 100,000 会导致超时间隔过期,并 Timer.Elapsed 触发事件,以及要设置取消请求。

注解

在当前任务完成之前,将不安排返回 Task 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith(Action<Task<TResult>,Object>, Object)

创建一个延续,该延续是传递的状态信息,并在目标 Task<TResult> 完成时执行。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^, System::Object ^> ^ continuationAction, System::Object ^ state);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>,object> continuationAction, object state);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>, obj> * obj -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult), Object), state As Object) As Task

参数

continuationAction
Action<Task<TResult>,Object>

完成时 Task<TResult> 要运行的操作。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续操作要使用的数据。

返回

新的延续 Task

例外

参数 continuationActionnull.

示例

以下示例创建一个在 2 和 20 之间传递整数的任务,并返回一个数组,其中包含该数字的前10 个指数(从 n 1 到 n10)。 然后,延续任务负责显示指数。 它同时传递先行数和原始数字,其指数为先行生成的数字。

using System;
using System.Threading;
using System.Threading.Tasks;

public class Example
{
   public static void Main()
   {
      var cts = new CancellationTokenSource();
      var token = cts.Token;

      // Get an integer to generate a list of its exponents.
      var rnd = new Random();
      var number = rnd.Next(2, 21);
      
      var t = Task.Factory.StartNew( (value) => { int n = (int) value;
                                                  long[] values = new long[10];
                                                  for (int ctr = 1; ctr <= 10; ctr++)
                                                     values[ctr - 1] = (long) Math.Pow(n, ctr);
                                                     
                                                  return values;
                                                }, number);
      var continuation = t.ContinueWith( (antecedent, value) => { Console.WriteLine("Exponents of {0}:", value);
                                                                  for (int ctr = 0; ctr <= 9; ctr++)
                                                                     Console.WriteLine("   {0} {1} {2} = {3:N0}",
                                                                                       value, "\u02C6", ctr + 1,
                                                                                       antecedent.Result[ctr]);
                                                                  Console.WriteLine();
                                                                }, number);
      continuation.Wait();
      cts.Dispose();
   }
}
// The example displays output like the following:
//       Exponents of 2:
//          2 ^ 1 = 2
//          2 ^ 2 = 4
//          2 ^ 3 = 8
//          2 ^ 4 = 16
//          2 ^ 5 = 32
//          2 ^ 6 = 64
//          2 ^ 7 = 128
//          2 ^ 8 = 256
//          2 ^ 9 = 512
//          2 ^ 10 = 1,024
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim cts As New CancellationTokenSource()
      Dim token As CancellationToken = cts.Token

      ' Get an integer to generate a list of its exponents.
      Dim rnd As New Random()
      Dim number As Integer = rnd.Next(2, 21)

      Dim t = Task.Factory.StartNew( Function(value)
                                        Dim n As Integer = CInt(value)
                                        Dim values(9) As Long
                                        For ctr As Integer = 1 To 10
                                           values(ctr - 1) = CLng(Math.Pow(n, ctr))
                                        Next
                                        return values
                                     End Function, number)
      Dim continuation = t.ContinueWith( Sub(antecedent, value)
                                            Console.WriteLine("Exponents of {0}:", value)
                                            For ctr As Integer = 0 To 9
                                               Console.WriteLine("   {0} {1} {2} = {3:N0}",
                                                                 value, ChrW(&h02C6), ctr + 1,
                                                                 antecedent.Result(ctr))
                                            Next
                                            Console.WriteLine()
                                         End Sub, number)
      continuation.Wait()

      cts.Dispose()
   End Sub
End Module
' The example displays output like the following:
'       Exponents of 2:
'          2 ^ 1 = 2
'          2 ^ 2 = 4
'          2 ^ 3 = 8
'          2 ^ 4 = 16
'          2 ^ 5 = 32
'          2 ^ 6 = 64
'          2 ^ 7 = 128
'          2 ^ 8 = 256
'          2 ^ 9 = 512
'          2 ^ 10 = 1,024

注解

在当前任务完成之前,将不安排返回 Task 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith(Action<Task<TResult>>)

创建在目标任务完成时异步执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^> ^ continuationAction);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>> continuationAction);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>> -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult))) As Task

参数

continuationAction
Action<Task<TResult>>

在前面的 Task<TResult> 操作完成时运行。 运行时,将委托作为参数传递已完成的任务。

返回

新的延续任务。

例外

参数 continuationActionnull.

示例

以下示例创建使用 Eratosthenes 的 Sieve 计算 1 与用户输入的值之间的质数的先行任务。 数组用于保存有关质数的信息。 数组索引表示数字,元素的值指示该数字是复合的(其值为 true)还是质数(其值为 false)。 然后,此任务将传递给延续任务,该任务负责从整数数组中提取质数并显示它们。

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

public class Example
{
   public static void Main(string[] args)
   {
      int upperBound = args.Length >= 1 ? Int32.Parse(args[0]) : 200;

      var t1 = Task.Run(() => { // True = composite.
                                // False = prime.
                                bool[] values = new bool[upperBound + 1];
                                for (int ctr = 2; ctr <= (int) Math.Sqrt(upperBound); ctr++) {
                                   if (!values[ctr]) {
                                      for (int product = ctr * ctr; product <= upperBound;
                                                                    product = product + ctr)
                                         values[product] = true;
                                   }
                                }
                                return values; });
      var t2 = t1.ContinueWith( (antecedent) => { // Create a list of prime numbers.
                                                  var  primes = new List<int>();
                                                  bool[] numbers = antecedent.Result;
                                                  string output = String.Empty;

                                                  for (int ctr = 1; ctr <= numbers.GetUpperBound(0); ctr++)
                                                     if (!numbers[ctr])
                                                        primes.Add(ctr);

                                                  // Create the output string.
                                                  for (int ctr = 0; ctr < primes.Count; ctr++) {
                                                     output += primes[ctr].ToString("N0");
                                                     if (ctr < primes.Count - 1)
                                                        output += ",  ";
                                                     if ((ctr + 1) % 8 == 0)
                                                        output += Environment.NewLine;
                                                  }
                                                  //Display the result.
                                                  Console.WriteLine("Prime numbers from 1 to {0}:\n",
                                                                    upperBound);
                                                  Console.WriteLine(output);
                                                });
      try {
         t2.Wait();
      }
      catch (AggregateException ae) {
         foreach (var e in ae.InnerExceptions)
            Console.WriteLine("{0}: {1}", e.GetType().Name, e.Message);
      }
   }
}
// The example displays output like the following:
//       Prime numbers from 1 to 400:
//
//       1,  2,  3,  5,  7,  11,  13,  17,
//       19,  23,  29,  31,  37,  41,  43,  47,
//       53,  59,  61,  67,  71,  73,  79,  83,
//       89,  97,  101,  103,  107,  109,  113,  127,
//       131,  137,  139,  149,  151,  157,  163,  167,
//       173,  179,  181,  191,  193,  197,  199,  211,
//       223,  227,  229,  233,  239,  241,  251,  257,
//       263,  269,  271,  277,  281,  283,  293,  307,
//       311,  313,  317,  331,  337,  347,  349,  353,
//       359,  367,  373,  379,  383,  389,  397,  401
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main(args() As String)
      Dim upperBound As Integer = If(args.Length >= 1, CInt(args(0)), 200)

      Dim t1 = Task.Run(Function()
                          ' True = composite.
                          ' False = prime.
                          Dim values(upperBound) As Boolean
                          For ctr = 2 To CInt(Math.Sqrt(upperBound))
                             If values(ctr) = False Then
                                For product = ctr * ctr To upperBound Step ctr
                                   values(product) = True
                                Next
                             End If
                          Next
                          Return values
                       End Function)

      Dim t2 = t1.ContinueWith(Sub(antecedent)
                                  ' Create a list of prime numbers.
                                  Dim primes As New List(Of Integer)()
                                  Dim numbers As Boolean() = antecedent.Result
                                  Dim output As String = String.Empty
                                  
                                  For ctr As Integer = 1 To numbers.GetUpperBound(0)
                                     If numbers(ctr) = False Then primes.Add(ctr)
                                  Next

                                  ' Create the output string.
                                  For ctr As Integer = 0 To primes.Count - 1
                                     output += primes(ctr).ToString("N0")
                                     If ctr < primes.Count - 1 Then output += ",  "
                                     If (ctr + 1) Mod 8 = 0 Then output += vbCrLf
                                  Next
                                  'Display the result.
                                  Console.WriteLine("Prime numbers from 1 to {0}:{1}",
                                                    upperBound, vbCrLf)
                                  Console.WriteLine(output)
                               End Sub)
      Try
         t2.Wait()
      Catch ae As AggregateException
         For Each e In ae.InnerExceptions
            Console.WriteLine("{0}: {1}", e.GetType().Name, e.Message)
         Next
      End Try
   End Sub
End Module
' The example displays output like the following:
'       Prime numbers from 1 to 400:
'
'       1,  2,  3,  5,  7,  11,  13,  17,
'       19,  23,  29,  31,  37,  41,  43,  47,
'       53,  59,  61,  67,  71,  73,  79,  83,
'       89,  97,  101,  103,  107,  109,  113,  127,
'       131,  137,  139,  149,  151,  157,  163,  167,
'       173,  179,  181,  191,  193,  197,  199,  211,
'       223,  227,  229,  233,  239,  241,  251,  257,
'       263,  269,  271,  277,  281,  283,  293,  307,
'       311,  313,  317,  331,  337,  347,  349,  353,
'       359,  367,  373,  379,  383,  389,  397,  401
' If cancellation is requested, the example displays output like the following:
'       The operation was cancelled.

注解

在当前任务完成之前,不会计划返回 Task 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith(Action<Task<TResult>>, TaskScheduler)

创建在目标 Task<TResult> 完成时异步执行的延续。

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task<TResult> ^> ^ continuationAction, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task ContinueWith(Action<System.Threading.Tasks.Task<TResult>> continuationAction, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Action<System.Threading.Tasks.Task<'Result>> * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task
Public Function ContinueWith (continuationAction As Action(Of Task(Of TResult)), scheduler As TaskScheduler) As Task

参数

continuationAction
Action<Task<TResult>>

完成时 Task<TResult> 要运行的操作。 运行时,将委托作为参数传递已完成的任务。

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

新的延续 Task

例外

参数 continuationActionnull.

-或-

参数 schedulernull.

注解

在当前任务完成之前,将不安排返回 Task 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, System::Object ^, TNewResult> ^ continuationFunction, System::Object ^ state, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,object,TNewResult> continuationFunction, object state, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, obj, 'NewResult> * obj * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), Object, TNewResult), state As Object, cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,Object,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续函数要使用的数据。

cancellationToken
CancellationToken

CancellationToken 分配给新任务。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 schedulernull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

已释放所提供的 CancellationToken 内容。

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

continuationFunction执行时,应返回一个 Task<TResult>。 此任务的完成状态将转移到从 Task<TResult>.ContinueWith 调用返回的任务。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, CancellationToken, TaskContinuationOptions, TaskScheduler)

创建一个根据中指定的 continuationOptions条件执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, TNewResult> ^ continuationFunction, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,TNewResult> continuationFunction, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, 'NewResult> * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), TNewResult), cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,TNewResult>

要根据中指定的 continuationOptions条件运行的函数。

运行时,委托将作为此已完成任务的参数传递。

cancellationToken
CancellationToken

CancellationToken 分配给新任务。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

Task<TResult>已处置。

-或-

CancellationTokenSource已释放创建的cancellationToken项。

参数 continuationFunctionnull.

-或-

参数 schedulernull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

continuationFunction执行时,应返回一个 Task<TResult>

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, TaskScheduler)

创建在目标 Task<TResult> 完成时执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, System::Object ^, TNewResult> ^ continuationFunction, System::Object ^ state, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,object,TNewResult> continuationFunction, object state, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, obj, 'NewResult> * obj * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), Object, TNewResult), state As Object, scheduler As TaskScheduler) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,Object,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续函数要使用的数据。

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 schedulernull.

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, TaskContinuationOptions)

创建在目标 Task<TResult> 完成时执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, System::Object ^, TNewResult> ^ continuationFunction, System::Object ^ state, System::Threading::Tasks::TaskContinuationOptions continuationOptions);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,object,TNewResult> continuationFunction, object state, System.Threading.Tasks.TaskContinuationOptions continuationOptions);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, obj, 'NewResult> * obj * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), Object, TNewResult), state As Object, continuationOptions As TaskContinuationOptions) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,Object,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续函数要使用的数据。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 continuationFunctionnull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

continuationFunction执行时,应返回一个 Task<TResult>。 此任务的完成状态将转移到从 ContinueWith 调用返回的任务。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object, CancellationToken)

创建在目标 Task<TResult> 完成时执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, System::Object ^, TNewResult> ^ continuationFunction, System::Object ^ state, System::Threading::CancellationToken cancellationToken);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,object,TNewResult> continuationFunction, object state, System.Threading.CancellationToken cancellationToken);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, obj, 'NewResult> * obj * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), Object, TNewResult), state As Object, cancellationToken As CancellationToken) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,Object,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续函数要使用的数据。

cancellationToken
CancellationToken

CancellationToken 分配给新任务。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 continuationFunctionnull.

已释放所提供的 CancellationToken 内容。

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, TaskContinuationOptions)

创建一个根据中指定的 continuationOptions条件执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, TNewResult> ^ continuationFunction, System::Threading::Tasks::TaskContinuationOptions continuationOptions);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,TNewResult> continuationFunction, System.Threading.Tasks.TaskContinuationOptions continuationOptions);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, 'NewResult> * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), TNewResult), continuationOptions As TaskContinuationOptions) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,TNewResult>

要根据中指定的 continuationOptions条件运行的函数。

运行时,将委托作为参数传递已完成的任务。

continuationOptions
TaskContinuationOptions

计划延续的时间及其行为方式的选项。 这包括条件,例如 OnlyOnCanceled,以及执行选项,例如 ExecuteSynchronously

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 continuationFunctionnull.

continuationOptions 参数指定了无效 TaskContinuationOptions值。

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

continuationFunction执行时,应返回一个 Task<TResult>

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, CancellationToken)

创建在目标 Task<TResult> 完成时异步执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, TNewResult> ^ continuationFunction, System::Threading::CancellationToken cancellationToken);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,TNewResult> continuationFunction, System.Threading.CancellationToken cancellationToken);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, 'NewResult> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), TNewResult), cancellationToken As CancellationToken) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,将委托作为参数传递已完成的任务。

cancellationToken
CancellationToken

CancellationToken 分配给新任务。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

Task<TResult>已处置。

-或-

CancellationTokenSource已释放创建的cancellationToken项。

参数 continuationFunctionnull.

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,Object,TNewResult>, Object)

创建在目标 Task<TResult> 完成时执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, System::Object ^, TNewResult> ^ continuationFunction, System::Object ^ state);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,object,TNewResult> continuationFunction, object state);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, obj, 'NewResult> * obj -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), Object, TNewResult), state As Object) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,Object,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,委托将传递已完成的任务和调用方提供的状态对象作为参数。

state
Object

一个对象,表示延续函数要使用的数据。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 continuationFunctionnull.

示例

以下示例创建一系列延续任务。 每个任务都提供方法的状态参数的ContinueWith(Action<Task,Object>, Object)当前时间、对象DateTime。 每个 DateTime 值表示创建继续任务的时间。 每个任务生成其结果的第二 DateTime 个值,该值表示任务完成的时间。 完成所有任务后,该示例显示每个延续任务开始和完成的日期和时间。

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

// Demonstrates how to associate state with task continuations.
class ContinuationState
{
   // Simluates a lengthy operation and returns the time at which
   // the operation completed.
   public static DateTime DoWork()
   {
      // Simulate work by suspending the current thread
      // for two seconds.
      Thread.Sleep(2000);

      // Return the current time.
      return DateTime.Now;
   }

   static void Main(string[] args)
   {
      // Start a root task that performs work.
      Task<DateTime> t = Task<DateTime>.Run(delegate { return DoWork(); });

      // Create a chain of continuation tasks, where each task is
      // followed by another task that performs work.
      List<Task<DateTime>> continuations = new List<Task<DateTime>>();
      for (int i = 0; i < 5; i++)
      {
         // Provide the current time as the state of the continuation.
         t = t.ContinueWith(delegate { return DoWork(); }, DateTime.Now);
         continuations.Add(t);
      }

      // Wait for the last task in the chain to complete.
      t.Wait();

      // Print the creation time of each continuation (the state object)
      // and the completion time (the result of that task) to the console.
      foreach (var continuation in continuations)
      {
         DateTime start = (DateTime)continuation.AsyncState;
         DateTime end = continuation.Result;

         Console.WriteLine("Task was created at {0} and finished at {1}.",
            start.TimeOfDay, end.TimeOfDay);
      }
   }
}

/* Sample output:
Task was created at 10:56:21.1561762 and finished at 10:56:25.1672062.
Task was created at 10:56:21.1610677 and finished at 10:56:27.1707646.
Task was created at 10:56:21.1610677 and finished at 10:56:29.1743230.
Task was created at 10:56:21.1610677 and finished at 10:56:31.1779883.
Task was created at 10:56:21.1610677 and finished at 10:56:33.1837083.
*/
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks

' Demonstrates how to associate state with task continuations.
Public Module ContinuationState
   ' Simluates a lengthy operation and returns the time at which
   ' the operation completed.
   Public Function DoWork() As Date
      ' Simulate work by suspending the current thread 
      ' for two seconds.
      Thread.Sleep(2000)

      ' Return the current time.
      Return Date.Now
   End Function

   Public Sub Main()
      ' Start a root task that performs work.
      Dim t As Task(Of Date) = Task(Of Date).Run(Function() DoWork())

      ' Create a chain of continuation tasks, where each task is
      ' followed by another task that performs work.
      Dim continuations As New List(Of Task(Of DateTime))()
      For i As Integer = 0 To 4
         ' Provide the current time as the state of the continuation.
         t = t.ContinueWith(Function(antecedent, state) DoWork(), DateTime.Now)
         continuations.Add(t)
      Next

      ' Wait for the last task in the chain to complete.
      t.Wait()

      ' Display the creation time of each continuation (the state object)
      ' and the completion time (the result of that task) to the console.
      For Each continuation In continuations
         Dim start As DateTime = CDate(continuation.AsyncState)
         Dim [end] As DateTime = continuation.Result

         Console.WriteLine("Task was created at {0} and finished at {1}.",
            start.TimeOfDay, [end].TimeOfDay)
      Next
   End Sub
End Module
' The example displays output like the following:
'       Task was created at 10:56:21.1561762 and finished at 10:56:25.1672062.
'       Task was created at 10:56:21.1610677 and finished at 10:56:27.1707646.
'       Task was created at 10:56:21.1610677 and finished at 10:56:29.1743230.
'       Task was created at 10:56:21.1610677 and finished at 10:56:31.1779883.
'       Task was created at 10:56:21.1610677 and finished at 10:56:33.1837083.

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>)

创建在目标 Task<TResult> 完成时异步执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, TNewResult> ^ continuationFunction);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,TNewResult> continuationFunction);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, 'NewResult> -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), TNewResult)) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,将委托作为参数传递已完成的任务。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 continuationFunctionnull.

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于

ContinueWith<TNewResult>(Func<Task<TResult>,TNewResult>, TaskScheduler)

创建在目标 Task<TResult> 完成时异步执行的延续。

public:
generic <typename TNewResult>
 System::Threading::Tasks::Task<TNewResult> ^ ContinueWith(Func<System::Threading::Tasks::Task<TResult> ^, TNewResult> ^ continuationFunction, System::Threading::Tasks::TaskScheduler ^ scheduler);
public System.Threading.Tasks.Task<TNewResult> ContinueWith<TNewResult>(Func<System.Threading.Tasks.Task<TResult>,TNewResult> continuationFunction, System.Threading.Tasks.TaskScheduler scheduler);
override this.ContinueWith : Func<System.Threading.Tasks.Task<'Result>, 'NewResult> * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'NewResult>
Public Function ContinueWith(Of TNewResult) (continuationFunction As Func(Of Task(Of TResult), TNewResult), scheduler As TaskScheduler) As Task(Of TNewResult)

类型参数

TNewResult

延续生成的结果的类型。

参数

continuationFunction
Func<Task<TResult>,TNewResult>

完成时 Task<TResult> 要运行的函数。 运行时,将委托作为参数传递已完成的任务。

scheduler
TaskScheduler

TaskScheduler 与延续任务关联并用于其执行。

返回

Task<TNewResult>

新的延续 Task<TResult>

例外

参数 continuationFunctionnull.

-或-

参数 schedulernull.

注解

在当前任务完成之前,将不安排返回 Task<TResult> 的执行,无论是由于运行到成功完成、因未经处理的异常而出错,还是由于取消而提前退出。

另请参阅

适用于