CoreTaskExtensionsCatchTException Method (Task, ActionTask, TException) |
Synchronously execute an exception handling continuation when a task completes in the
Canceled or
Faulted state. If the
antecedent task completes successfully, or if the
Exception it
provides is not a
TException wrapped in an
AggregateException, the status of the antecedent is directly applied to
the task returned by this method. Otherwise, the status of the cleanup operation is
directly applied to the task returned by this method.
Namespace: Rackspace.ThreadingAssembly: Rackspace.Threading (in Rackspace.Threading.dll) Version: 1.1.0.0
Syntax
public static Task Catch<TException>(
this Task task,
Action<Task, TException> handler
)
where TException : Exception
<ExtensionAttribute>
Public Shared Function Catch(Of TException As Exception) (
task As Task,
handler As Action(Of Task, TException)
) As Task
public:
[ExtensionAttribute]
generic<typename TException>
where TException : Exception
static Task^ Catch(
Task^ task,
Action<Task^, TException>^ handler
)
[<ExtensionAttribute>]
static member Catch :
task : Task *
handler : Action<Task, 'TException> -> Task when 'TException : Exception
Parameters
- task
- Type: System.Threading.TasksTask
The antecedent task. - handler
- Type: SystemActionTask, TException
The exception handler continuation action to execute when task completes with an exception of type TException.
Type Parameters
- TException
- The type of exception which is handled by handler.
Return Value
Type:
TaskA
Task representing the asynchronous operation.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type
Task. 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
{
await task.ConfigureAwait(false);
}
catch (TException ex)
{
handler(task, ex);
}
This method is capable of handling Canceled antecedent
tasks when TException is assignable from
TaskCanceledException.
This method ensures that exception information provided by a faulted or canceled
task is not wrapped in an additional AggregateException.
Notes to Callers |
Since the continuation is executed synchronously, this method should only be used for
lightweight exception handler methods. For non-trivial exception handlers, use a
Task for the exception handling operation and call
CatchTException(Task, FuncTask, TException, Task)
instead.
|
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
See Also