TaskExtensions.Unwrap Method (Task<Task>)

Creates a proxy Task that represents the asynchronous operation of a Task<Task>.

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


<ExtensionAttribute> _
Public Shared Function Unwrap ( _
    task As Task(Of Task) _
) As Task
public static Task Unwrap(
    this Task<Task> task


Return Value

Type: System.Threading.Tasks.Task
A Task that represents the asynchronous operation of the provided System.Threading.Tasks.Task(Of Task).

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type Task<Task>. When you use instance method syntax to call this method, omit the first parameter.


Exception Condition

The exception that is thrown if the task argument is null.


It is often useful to be able to return a Task from a Task<TResult>, where the inner Task represents work done as part of the outer Task<TResult>. However, doing so results in a Task<Task> (C#) or Task (Of Task) (Visual Basic), which, if not dealt with carefully, could produce unexpected behavior. Unwrap solves this problem by creating a proxy Task that represents the entire asynchronous operation of such a task.


The following example shows how to unwrap a task:

Version Information


Supported in: 5


For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.