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TaskFactory.ContinueWhenAll Method (Task[], Action(Task[]))

Creates a continuation task that starts when a set of specified tasks has completed.

Namespace:  System.Threading.Tasks
Assemblies:   mscorlib (in mscorlib.dll)
  System.Threading.Tasks (in System.Threading.Tasks.dll)

member ContinueWhenAll : 
        tasks:Task[] * 
        continuationAction:Action<Task[]> -> Task

Parameters

tasks
Type: System.Threading.Tasks.Task[]

The array of tasks from which to continue.

continuationAction
Type: System.Action(Task[])

The action delegate to execute when all tasks in the tasks array have completed.

Return Value

Type: System.Threading.Tasks.Task
The new continuation task.

ExceptionCondition
ObjectDisposedException

An element in the tasks array has been disposed.

ArgumentNullException

The tasks array is a null reference (Nothing in Visual Basic).

-or-

The continuationAction argument is a null reference (Nothing in Visual Basic).

ArgumentException

The tasks array is empty or contains a null value.

The ContinueWhenAll method executes the continuationAction delegate when all tasks in the tasks array have completed, regardless of their completion status.

Exceptions thrown by tasks in the tasks array are not available to the continuation task through structured exception handling. You can determine which exceptions were thrown by examining the Task.Exception property of each task in the tasks array. To use structured exception handling to handle exceptions thrown by tasks in the tasks array, call the Task.WaitAll(Task[]) method.

The following example launches separate tasks that use a regular expression to count the number of words in a set of text files. The ContinueWhenAll method is used to launch a task that displays the total word count when all the antecedent tasks have completed.

No code example is currently available or this language may not be supported.

The call to the continuation task's Task.Wait method does not allow it to handle exceptions thrown by the antecedent tasks, so the example examines the Task.Status property of each antecedent task to determine whether the task succeeded.

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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