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Task::WaitAll Method (array<Task>, Int32, CancellationToken)

Waits for all of the provided Task objects to complete execution within a specified number of milliseconds or until the wait is cancelled.

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

static bool WaitAll(
	array<Task^>^ tasks, 
	int millisecondsTimeout, 
	CancellationToken cancellationToken


Type: array<System.Threading.Tasks::Task>

An array of Task instances on which to wait.

Type: System::Int32

The number of milliseconds to wait, or Infinite (-1) to wait indefinitely.

Type: System.Threading::CancellationToken

A CancellationToken to observe while waiting for the tasks to complete.

Return Value

Type: System::Boolean
true if all of the Task instances completed execution within the allotted time; otherwise, false.


One or more of the Task objects in tasks has been disposed.


The tasks argument is nullptr.


At least one of the Task instances was canceled. If a task was canceled, the AggregateException contains an OperationCanceledException in its InnerExceptions collection.


An exception was thrown during the execution of at least one of the Task instances.


millisecondsTimeout is a negative number other than -1, which represents an infinite time-out.


The tasks argument contains a null element.


The cancellationToken was canceled.

The cancellationToken argument is used to cancel the wait operation. Cancellation of the tasks is a distinct operation, and is signaled by the AggregateException noted above.

.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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