Task.Status Task.Status Task.Status Task.Status Property

定義

このタスクの TaskStatus を取得します。Gets the TaskStatus of this task.

public:
 property System::Threading::Tasks::TaskStatus Status { System::Threading::Tasks::TaskStatus get(); };
public System.Threading.Tasks.TaskStatus Status { get; }
member this.Status : System.Threading.Tasks.TaskStatus
Public ReadOnly Property Status As TaskStatus

プロパティ値

このタスク インスタンスの現在の TaskStatusThe current TaskStatus of this task instance.

次の例では、カウンターが200万の値にインクリメントされるまでループするタスクを20個作成します。The following example creates 20 tasks that will loop until a counter is incremented to a value of 2 million. 最初の10個のタスクが200万に達した場合、キャンセルトークンは取り消され、カウンターが200万に達していないすべてのタスクは取り消されます。When the first 10 tasks reach 2 million, the cancellation token is cancelled, and any tasks whose counters have not reached 2 million are cancelled. この例では、各タスクの Status プロパティを調べて、正常に完了したか取り消されたかを示します。The example then examines the Status property of each task to indicate whether it completed successfully or was cancelled. 完了したものについては、タスクによって返された値が表示されます。For those that completed, it displays the value returned by the task.

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

public class Example
{
   public static void Main()
   {
      var tasks = new List<Task<int>>();
      var source = new CancellationTokenSource();
      var token = source.Token;
      int completedIterations = 0;

      for (int n = 0; n <= 19; n++)
         tasks.Add(Task.Run( () => { int iterations = 0;
                                     for (int ctr = 1; ctr <= 2000000; ctr++) {
                                         token.ThrowIfCancellationRequested();
                                         iterations++;
                                     }
                                     Interlocked.Increment(ref completedIterations);
                                     if (completedIterations >= 10)
                                        source.Cancel();
                                     return iterations; }, token));

      Console.WriteLine("Waiting for the first 10 tasks to complete...\n");
      try  {
         Task.WaitAll(tasks.ToArray());
      }
      catch (AggregateException) {
         Console.WriteLine("Status of tasks:\n");
         Console.WriteLine("{0,10} {1,20} {2,14:N0}", "Task Id",
                           "Status", "Iterations");
         foreach (var t in tasks)
            Console.WriteLine("{0,10} {1,20} {2,14}",
                              t.Id, t.Status,
                              t.Status != TaskStatus.Canceled ? t.Result.ToString("N0") : "n/a");
      }
   }
}
// The example displays output like the following:
//    Waiting for the first 10 tasks to complete...
//    Status of tasks:
//
//       Task Id               Status     Iterations
//             1      RanToCompletion      2,000,000
//             2      RanToCompletion      2,000,000
//             3      RanToCompletion      2,000,000
//             4      RanToCompletion      2,000,000
//             5      RanToCompletion      2,000,000
//             6      RanToCompletion      2,000,000
//             7      RanToCompletion      2,000,000
//             8      RanToCompletion      2,000,000
//             9      RanToCompletion      2,000,000
//            10             Canceled            n/a
//            11             Canceled            n/a
//            12             Canceled            n/a
//            13             Canceled            n/a
//            14             Canceled            n/a
//            15             Canceled            n/a
//            16      RanToCompletion      2,000,000
//            17             Canceled            n/a
//            18             Canceled            n/a
//            19             Canceled            n/a
//            20             Canceled            n/a
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks

Module Example

   Public Sub Main()
      Dim tasks As New List(Of Task(Of Integer))()
      Dim source As New CancellationTokenSource
      Dim token As CancellationToken = source.Token
      Dim completedIterations As Integer = 0
      
      For n As Integer = 0 To 19
         tasks.Add(Task.Run( Function()
                                Dim iterations As Integer= 0
                                For ctr As Long = 1 To 2000000
                                   token.ThrowIfCancellationRequested()
                                   iterations += 1
                                Next
                                Interlocked.Increment(completedIterations)
                                If completedIterations >= 10 Then source.Cancel()
                                Return iterations
                             End Function, token))
      Next

      Console.WriteLine("Waiting for the first 10 tasks to complete... ")
      Try
         Task.WaitAll(tasks.ToArray())
      Catch e As AggregateException
         Console.WriteLine("Status of tasks:")
         Console.WriteLine()
         Console.WriteLine("{0,10} {1,20} {2,14}", "Task Id",
                           "Status", "Iterations")
         For Each t In tasks
            Console.WriteLine("{0,10} {1,20} {2,14}",
                              t.Id, t.Status,
                              If(t.Status <> TaskStatus.Canceled,
                                 t.Result.ToString("N0"), "n/a"))
         Next
      End Try
   End Sub
End Module
' The example displays output like the following:
'    Waiting for the first 10 tasks to complete...
'    Status of tasks:
'
'       Task Id               Status     Iterations
'             1      RanToCompletion      2,000,000
'             2      RanToCompletion      2,000,000
'             3      RanToCompletion      2,000,000
'             4      RanToCompletion      2,000,000
'             5      RanToCompletion      2,000,000
'             6      RanToCompletion      2,000,000
'             7      RanToCompletion      2,000,000
'             8      RanToCompletion      2,000,000
'             9      RanToCompletion      2,000,000
'            10             Canceled            n/a
'            11             Canceled            n/a
'            12             Canceled            n/a
'            13             Canceled            n/a
'            14             Canceled            n/a
'            15             Canceled            n/a
'            16      RanToCompletion      2,000,000
'            17             Canceled            n/a
'            18             Canceled            n/a
'            19             Canceled            n/a
'            20             Canceled            n/a

注釈

@No__t-0 プロパティの値を取得しても、タスクが完了するまで呼び出し元のスレッドはブロックされません。Retrieving the value of the Task.Status property does not block the calling thread until the task has completed.

詳細と例については、「継続タスクを使用したタスクの連結」と「how を参照してください。タスクとその子を取り消す」を参照してください。For more information and an example, see Chaining Tasks by Using Continuation Tasks and How to: Cancel a Task and Its Children.

適用対象