FromAsync Method (Func(AsyncCallback, Object, IAsyncResult), Action(IAsyncResult), Object, TaskCreationOptions)
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TaskFactory.FromAsync Method (Func<AsyncCallback, Object, IAsyncResult>, Action<IAsyncResult>, Object, TaskCreationOptions)

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Creates a Task that represents a pair of begin and end methods that conform to the Asynchronous Programming Model pattern.

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

public Task FromAsync(
	Func<AsyncCallback, Object, IAsyncResult> beginMethod,
	Action<IAsyncResult> endMethod,
	Object state,
	TaskCreationOptions creationOptions


Type: System.Func<AsyncCallback, Object, IAsyncResult>
The delegate that begins the asynchronous operation.
Type: System.Action<IAsyncResult>
The delegate that ends the asynchronous operation.
Type: System.Object
An object containing data to be used by the beginMethod delegate.
Type: System.Threading.Tasks.TaskCreationOptions
The TaskCreationOptions value that controls the behavior of the created Task.

Return Value

Type: System.Threading.Tasks.Task
The created Task that represents the asynchronous operation.


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


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


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

This method throws any exceptions thrown by the beginMethod. The TaskCreationOptions values PreferFairness, LongRunning and AttachedToParent are all mutually exclusive. In the FromAsync methods, either LongRunning or AttachedToParent by themselves will cause an ArgumentOutOfRangeException to be thrown.

Windows Phone OS

Supported in: 8.1, 8.0

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