Task.WaitAny Method (System.Threading.Tasks) (original) (raw)

Source:

Task.cs

Source:

Task.cs

Source:

Task.cs

Source:

Task.cs

Waits for any of the provided Task objects to complete execution.

public:
 static int WaitAny(... cli::array <System::Threading::Tasks::Task ^> ^ tasks);

public static int WaitAny(params System.Threading.Tasks.Task[] tasks);

static member WaitAny : System.Threading.Tasks.Task[] -> int

Public Shared Function WaitAny (ParamArray tasks As Task()) As Integer

Parameters

tasks

Task[]

An array of Task instances on which to wait.

Returns

The index of the completed Task object in the tasks array.

Exceptions

The Task has been disposed.

The tasks argument is null.

The tasks argument contains a null element.

Examples

The following example launches five tasks, each of which sleeps for a minimum of 50 milliseconds or a maximum of 1,050 milliseconds. The WaitAny method then waits for any of the tasks to complete. The example displays the task ID of the task that ended the wait, as well as the current status of all the tasks.

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

public class Example
{
   public static void Main()
   {
      Task[] tasks = new Task[5];
      for (int ctr = 0; ctr <= 4; ctr++) {
         int factor = ctr;
         tasks[ctr] = Task.Run(() => Thread.Sleep(factor * 250 + 50));
      }
      int index = Task.WaitAny(tasks);
      Console.WriteLine("Wait ended because task #{0} completed.",
                        tasks[index].Id);
      Console.WriteLine("\nCurrent Status of Tasks:");
      foreach (var t in tasks)
         Console.WriteLine("   Task {0}: {1}", t.Id, t.Status);
   }
}
// The example displays output like the following:
//       Wait ended because task #1 completed.
//
//       Current Status of Tasks:
//          Task 1: RanToCompletion
//          Task 2: Running
//          Task 3: Running
//          Task 4: Running
//          Task 5: Running

open System.Threading
open System.Threading.Tasks

let tasks =
    [| for factor = 0 to 4 do
           Task.Run(fun () -> Thread.Sleep(factor * 250 + 50)) |]

let index = Task.WaitAny tasks
printfn $"Wait ended because task #{tasks[index].Id} completed."
printfn "\nCurrent Status of Tasks:"

for t in tasks do
    printfn $"   Task {t.Id}: {t.Status}"


// The example displays output like the following:
//       Wait ended because task #1 completed.
//
//       Current Status of Tasks:
//          Task 1: RanToCompletion
//          Task 2: Running
//          Task 3: Running
//          Task 4: Running
//          Task 5: Running

Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim tasks(4) As Task
      For ctr As Integer = 0 To 4
         Dim factor As Integer = ctr
         tasks(ctr) = Task.Run(Sub() Thread.Sleep(factor * 250 + 50))
      Next
      Dim index As Integer = Task.WaitAny(tasks)

      Console.WriteLine("Wait ended because task #{0} completed.",
                        tasks(index).Id)
      Console.WriteLine()
      Console.WriteLine("Current Status of Tasks:")
      For Each t In tasks
         Console.WriteLine("   Task {0}: {1}", t.Id, t.Status)
      Next
   End Sub
End Module
' The example displays output like the following:
'       Wait ended because task #1 completed.
'
'       Current Status of Tasks:
'          Task 1: RanToCompletion
'          Task 2: Running
'          Task 3: Running
'          Task 4: Running
'          Task 5: Running

Applies to