CancellationTokenSource.Cancel 메서드

정의

취소 요청을 전달합니다.Communicates a request for cancellation.

오버로드

Cancel()

취소 요청을 전달합니다.Communicates a request for cancellation.

Cancel(Boolean)

예외가 발생한 경우 취소 요청을 전달하고 나머지 콜백과 취소 가능한 작업을 처리해야 하는지를 지정합니다.Communicates a request for cancellation, and specifies whether remaining callbacks and cancelable operations should be processed if an exception occurs.

Cancel()

취소 요청을 전달합니다.Communicates a request for cancellation.

public:
 void Cancel();
public void Cancel ();
member this.Cancel : unit -> unit
Public Sub Cancel ()

예외

CancellationTokenSource가 삭제되었습니다.This CancellationTokenSource has been disposed.

연결된 CancellationToken에 등록된 콜백에 의해 throw되는 모든 예외를 포함하는 집계 예외.An aggregate exception containing all the exceptions thrown by the registered callbacks on the associated CancellationToken.

예제

다음 예제에서는 정수 값 10 11 개의 다양 한 계측에서 읽는 데이터 컬렉션 애플리케이션을 에뮬레이트 하려면 난수 생성기를 사용 합니다.The following example uses a random number generator to emulate a data collection application that reads 10 integral values from eleven different instruments. 값이 0 이면 하나의 계측에 대해 측정값이 실패 했음을 나타냅니다 .이 경우 작업을 취소 하 고 전체 평균을 계산 하지 않아야 합니다.A value of zero indicates that the measurement has failed for one instrument, in which case the operation should be cancelled and no overall mean should be computed.

작업의 가능한 취소를 처리 하기 위해이 예제에서는 개체에 CancellationTokenSource 전달 되는 취소 토큰을 생성 하는 개체를 인스턴스화합니다 TaskFactory .To handle the possible cancellation of the operation, the example instantiates a CancellationTokenSource object that generates a cancellation token which is passed to a TaskFactory object. TaskFactory그런 다음 개체는 특정 계기에 대 한 판독값을 담당 하는 각 작업에 취소 토큰을 전달 합니다.The TaskFactory object in turn passes the cancellation token to each of the tasks responsible for collecting readings for a particular instrument. TaskFactory.ContinueWhenAll<TAntecedentResult,TResult>(Task<TAntecedentResult>[], Func<Task<TAntecedentResult>[],TResult>, CancellationToken)모든 판독값이 성공적으로 수집 된 후에만 평균이 계산 되도록 메서드를 호출 합니다.The TaskFactory.ContinueWhenAll<TAntecedentResult,TResult>(Task<TAntecedentResult>[], Func<Task<TAntecedentResult>[],TResult>, CancellationToken) method is called to ensure that the mean is computed only after all readings have been gathered successfully. 작업이 취소 되었기 때문에 작업이 취소 되지 않은 경우 메서드를 호출 하면 TaskFactory.ContinueWhenAll 예외가 throw 됩니다.If a task has not because it has been cancelled, the call to the TaskFactory.ContinueWhenAll method throws an exception.

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

public class Example
{
   public static void Main()
   {
      // Define the cancellation token.
      CancellationTokenSource source = new CancellationTokenSource();
      CancellationToken token = source.Token;

      Random rnd = new Random();
      Object lockObj = new Object();
      
      List<Task<int[]>> tasks = new List<Task<int[]>>();
      TaskFactory factory = new TaskFactory(token);
      for (int taskCtr = 0; taskCtr <= 10; taskCtr++) {
         int iteration = taskCtr + 1;
         tasks.Add(factory.StartNew( () => {
                                       int value;
                                       int[] values = new int[10];
                                       for (int ctr = 1; ctr <= 10; ctr++) {
                                          lock (lockObj) {
                                             value = rnd.Next(0,101);
                                          }
                                          if (value == 0) { 
                                             source.Cancel();
                                             Console.WriteLine("Cancelling at task {0}", iteration);
                                             break;
                                          }   
                                          values[ctr-1] = value; 
                                       }
                                       return values;
                                    }, token));   
      }
      try {
         Task<double> fTask = factory.ContinueWhenAll(tasks.ToArray(), 
                                                      (results) => {
                                                         Console.WriteLine("Calculating overall mean...");
                                                         long sum = 0;
                                                         int n = 0; 
                                                         foreach (var t in results) {
                                                            foreach (var r in t.Result) {
                                                                  sum += r;
                                                                  n++;
                                                               }
                                                         }
                                                         return sum/(double) n;
                                                      } , token);
         Console.WriteLine("The mean is {0}.", fTask.Result);
      }   
      catch (AggregateException ae) {
         foreach (Exception e in ae.InnerExceptions) {
            if (e is TaskCanceledException)
               Console.WriteLine("Unable to compute mean: {0}", 
                                 ((TaskCanceledException) e).Message);
            else
               Console.WriteLine("Exception: " + e.GetType().Name);
         }
      }
      finally {
         source.Dispose();
      }
   }
}
// Repeated execution of the example produces output like the following:
//       Cancelling at task 5
//       Unable to compute mean: A task was canceled.
//       
//       Cancelling at task 10
//       Unable to compute mean: A task was canceled.
//       
//       Calculating overall mean...
//       The mean is 5.29545454545455.
//       
//       Cancelling at task 4
//       Unable to compute mean: A task was canceled.
//       
//       Cancelling at task 5
//       Unable to compute mean: A task was canceled.
//       
//       Cancelling at task 6
//       Unable to compute mean: A task was canceled.
//       
//       Calculating overall mean...
//       The mean is 4.97363636363636.
//       
//       Cancelling at task 4
//       Unable to compute mean: A task was canceled.
//       
//       Cancelling at task 5
//       Unable to compute mean: A task was canceled.
//       
//       Cancelling at task 4
//       Unable to compute mean: A task was canceled.
//       
//       Calculating overall mean...
//       The mean is 4.86545454545455.
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      ' Define the cancellation token.
      Dim source As New CancellationTokenSource()
      Dim token As CancellationToken = source.Token

      Dim lockObj As New Object()
      Dim rnd As New Random

      Dim tasks As New List(Of Task(Of Integer()))
      Dim factory As New TaskFactory(token)
      For taskCtr As Integer = 0 To 10
         Dim iteration As Integer = taskCtr + 1
         tasks.Add(factory.StartNew(Function()
                                       Dim value, values(9) As Integer
                                       For ctr As Integer = 1 To 10
                                          SyncLock lockObj
                                             value = rnd.Next(0,101)
                                          End SyncLock
                                          If value = 0 Then 
                                             source.Cancel
                                             Console.WriteLine("Cancelling at task {0}", iteration)
                                             Exit For
                                          End If   
                                          values(ctr-1) = value 
                                       Next
                                       Return values
                                    End Function, token))   
         
      Next
      Try
         Dim fTask As Task(Of Double) = factory.ContinueWhenAll(tasks.ToArray(), 
                                                         Function(results)
                                                            Console.WriteLine("Calculating overall mean...")
                                                            Dim sum As Long
                                                            Dim n As Integer 
                                                            For Each t In results
                                                               For Each r In t.Result
                                                                  sum += r
                                                                  n+= 1
                                                               Next
                                                            Next
                                                            Return sum/n
                                                         End Function, token)
         Console.WriteLine("The mean is {0}.", fTask.Result)
      Catch ae As AggregateException
         For Each e In ae.InnerExceptions
            If TypeOf e Is TaskCanceledException
               Console.WriteLine("Unable to compute mean: {0}", 
                                 CType(e, TaskCanceledException).Message)
            Else
               Console.WriteLine("Exception: " + e.GetType().Name)
            End If   
         Next
      Finally
         source.Dispose()
      End Try                                                          
   End Sub
End Module
' Repeated execution of the example produces output like the following:
'       Cancelling at task 5
'       Unable to compute mean: A task was canceled.
'       
'       Cancelling at task 10
'       Unable to compute mean: A task was canceled.
'       
'       Calculating overall mean...
'       The mean is 5.29545454545455.
'       
'       Cancelling at task 4
'       Unable to compute mean: A task was canceled.
'       
'       Cancelling at task 5
'       Unable to compute mean: A task was canceled.
'       
'       Cancelling at task 6
'       Unable to compute mean: A task was canceled.
'       
'       Calculating overall mean...
'       The mean is 4.97363636363636.
'       
'       Cancelling at task 4
'       Unable to compute mean: A task was canceled.
'       
'       Cancelling at task 5
'       Unable to compute mean: A task was canceled.
'       
'       Cancelling at task 4
'       Unable to compute mean: A task was canceled.
'       
'       Calculating overall mean...
'       The mean is 4.86545454545455.

설명

연결 된에는 취소에 대 한 알림이 표시 되 CancellationToken 고가 true를 반환 하는 상태로 전환 됩니다 IsCancellationRequested .The associated CancellationToken will be notified of the cancellation and will transition to a state where IsCancellationRequested returns true.

에 등록 된 모든 콜백 또는 취소할 수 있는 작업이 CancellationToken 실행 됩니다.Any callbacks or cancelable operations registered with the CancellationToken will be executed.

로 등록 된 취소할 수 있는 작업 및 콜백은 예외를 throw 하지 않는 것이 좋습니다 CancellationToken .We recommend that cancelable operations and callbacks registered with CancellationToken not throw exceptions.

이 Cancel의 오버 로드는 AggregateException 예외를 throw 하는 한 콜백에서 다른 등록 된 콜백이 실행 되는 것을 방지 하지 않도록에 throw 된 모든 예외를 집계 합니다.This overload of Cancel will aggregate any exceptions thrown into an AggregateException, such that one callback throwing an exception will not prevent other registered callbacks from being executed.

적용 대상

Cancel(Boolean)

예외가 발생한 경우 취소 요청을 전달하고 나머지 콜백과 취소 가능한 작업을 처리해야 하는지를 지정합니다.Communicates a request for cancellation, and specifies whether remaining callbacks and cancelable operations should be processed if an exception occurs.

public:
 void Cancel(bool throwOnFirstException);
public void Cancel (bool throwOnFirstException);
member this.Cancel : bool -> unit
Public Sub Cancel (throwOnFirstException As Boolean)

매개 변수

throwOnFirstException
Boolean

예외를 즉시 전파해야 하는 경우 true이고, 그렇지 않으면 false입니다.true if exceptions should immediately propagate; otherwise, false.

예외

CancellationTokenSource가 삭제되었습니다.This CancellationTokenSource has been disposed.

연결된 CancellationToken에 등록된 콜백에 의해 throw되는 모든 예외를 포함하는 집계 예외.An aggregate exception containing all the exceptions thrown by the registered callbacks on the associated CancellationToken.

설명

연결 된에는 취소에 대 한 알림이 표시 되 CancellationToken 고가 반환 되는 상태로 전환 됩니다 IsCancellationRequested true .The associated CancellationToken will be notified of the cancellation and will transition to a state where IsCancellationRequested returns true.

에 등록 된 모든 콜백 또는 취소할 수 있는 작업이 CancellationToken 실행 됩니다.Any callbacks or cancelable operations registered with the CancellationToken will be executed. 콜백은 LIFO 순서로 동기적으로 실행 됩니다.Callbacks will be executed synchronously in LIFO order.

로 등록 된 취소할 수 있는 작업 및 콜백은 예외를 throw 하지 않는 것이 좋습니다 CancellationToken .We recommend that cancelable operations and callbacks registered with CancellationToken not throw exceptions.

throwOnFirstException가 이면 true 예외는에 대 한 호출에서 즉시 전파 되며 Cancel 나머지 콜백과 취소할 수 있는 작업이 처리 되지 않습니다.If throwOnFirstException is true, an exception will immediately propagate out of the call to Cancel, preventing the remaining callbacks and cancelable operations from being processed.

throwOnFirstException가 인 경우 false 이 오버 로드는 AggregateException 예외를 throw 하는 한 콜백에서 다른 등록 된 콜백이 실행 되는 것을 방지 하지 않도록에 throw 된 모든 예외를 집계 합니다.If throwOnFirstException is false, this overload will aggregate any exceptions thrown into an AggregateException, such that one callback throwing an exception will not prevent other registered callbacks from being executed.

적용 대상