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TaskFactory<TResult>.StartNew Method (Func<TResult>, CancellationToken, TaskCreationOptions, TaskScheduler)

Creates and starts a TaskFactory<TResult>.

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

public Task<TResult> StartNew(
	Func<TResult> function,
	CancellationToken cancellationToken,
	TaskCreationOptions creationOptions,
	TaskScheduler scheduler


Type: System.Func<TResult>
A function delegate that returns the future result to be available through the TaskFactory<TResult>.
Type: System.Threading.CancellationToken
The CancellationToken that will be assigned to the new task.
Type: System.Threading.Tasks.TaskCreationOptions
A TaskCreationOptions value that controls the behavior of the created TaskFactory<TResult>.
Type: System.Threading.Tasks.TaskScheduler
The TaskScheduler that is used to schedule the created TaskFactory<TResult>.


The CancellationTokenSource that created cancellationToken has already been disposed.


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


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


The exception that is thrown when the creationOptions argument specifies an invalid TaskCreationOptions value.

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

However, unless creation and scheduling must be separated, StartNew is the recommended approach for both simplicity and performance.

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.