CoreTaskExtensionsThenTSource Method (TaskTSource, FuncTaskTSource, Task, Boolean) |
Execute a continuation task when a task completes. The continuation
task is synchronously created by a continuation function, and then unwrapped to
form the result of this method. The supportsErrors
parameter specifies whether the continuation is executed if the antecedent task is faulted.
Namespace: Rackspace.ThreadingAssembly: Rackspace.Threading (in Rackspace.Threading.dll) Version: 1.1.0.0
Syntax
public static Task Then<TSource>(
this Task<TSource> task,
Func<Task<TSource>, Task> continuationFunction,
bool supportsErrors
)
<ExtensionAttribute>
Public Shared Function Then(Of TSource) (
task As Task(Of TSource),
continuationFunction As Func(Of Task(Of TSource), Task),
supportsErrors As Boolean
) As Task
public:
[ExtensionAttribute]
generic<typename TSource>
static Task^ Then(
Task<TSource>^ task,
Func<Task<TSource>^, Task^>^ continuationFunction,
bool supportsErrors
)
[<ExtensionAttribute>]
static member Then :
task : Task<'TSource> *
continuationFunction : Func<Task<'TSource>, Task> *
supportsErrors : bool -> Task
Parameters
- task
- Type: System.Threading.TasksTaskTSource
The antecedent task. - continuationFunction
- Type: SystemFuncTaskTSource, Task
The continuation function to execute when task completes. The continuation function returns a Task which provides the final result of the continuation. - supportsErrors
- Type: SystemBoolean
if the continuationFunction properly handles a faulted antecedent task; otherwise, .
Type Parameters
- TSource
- The type of the result produced by the antecedent TaskTResult.
Return Value
Type:
TaskA
Task representing the unwrapped asynchronous operation.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type
TaskTSource. When you use instance method syntax to call this method, omit the first parameter. For more information, see
Extension Methods (Visual Basic) or
Extension Methods (C# Programming Guide).
Exceptions
Remarks
This code implements support for the following construct without requiring the use of
/
.
try
{
TSource source = await task.ConfigureAwait(false);
}
catch
{
if (!supportsErrors)
throw;
}
await continuationFunction(task).ConfigureAwait(false);
If the antecedent task is canceled, or faulted with supportsErrors
set to , the status
of the antecedent is directly applied to the task returned by this method; it is
not wrapped in an additional AggregateException.
Notes to Callers |
Since the continuationFunction is executed synchronously, this
method should only be used for lightweight continuation functions. This restriction
applies only to continuationFunction itself, not to the
Task returned by it.
|
Version Information
.NET for Windows Store apps
Supported in: Windows 8
.NET Framework
Supported in: 4.5, 4.0, 3.5
Portable Class Library
Supported in: Portable Class Library (Legacy), Portable Class Library
Rackspace Threading Library
Supported in: 1.1, 1.0
See Also