TaskFactory::StartNew Method (Action<Object^>^, Object^, CancellationToken)


Creates and starts a Task.

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

Task^ StartNew(
	Action<Object^>^ action,
	Object^ state,
	CancellationToken cancellationToken


Type: System::Action<Object^>^

The action delegate to execute asynchronously.

Type: System::Object^

An object containing data to be used by the action delegate.

Type: System.Threading::CancellationToken

The CancellationToken that will be assigned to the new Task

Return Value

Type: System.Threading.Tasks::Task^

The started Task.

Exception Condition

The provided CancellationToken has already been disposed.


The exception that is thrown when the action argument is null.

Calling StartNew is functionally equivalent to creating a Task using one of its constructors and then calling Start to schedule it for execution.

Starting with the .NET Framework 4.5, you can use the Run method with an Action object as a quick way to call StartNew with default parameters. For more information and code examples, see Task.Run vs Task.Factory.StartNew in the Parallel Programming with .NET blog.

The following example defines an array of 6-letter words. Each word is then passed to an Action<T> delegate, which scrambles the word and displays the original word and its scrambled version.

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

Note that the example initializes a single random number generator, which is protected by a lock. For the need of a lock, see "The System.Random class and thread safety" in the Random class topic. To handle the possibility of corruption of the random number generator, a cancellation token is passed to task. If two random numbers equal zero, the method assumes that the random number generator is corrupted and sets the cancellation token. Before sorting the chars array that contains the six characters in a word, the method calls the CancellationToken::ThrowIfCancellationRequested method to throw an OperationCanceledException if the token has been canceled.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Available since 5.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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