4

After reading a recent MSDN Magazine article about the Task scheduler I was hoping (and actually quite excited) that using it would benefit my use of WCF generated proxies.

I was hoping to get some of the following benefits :

  • 1) Ability to abort a running WCF operation (I'm not expecting this to stop the operation on the server - I'd just like to be able to signal that 'I don't want the result for this task'. This is especially common in UI where someone repeatedly selects items from a grid that trigger service calls.)
  • 2) Ability to start a task at some point other than when it was created - I'm not sure I really need this, I just thought it might be nice to generate a task and not immediately run it. After all I thought that was the whole point of tasks.
  • 3) Bindable properties - so I can bind my WCF UI to IsCompleted and let the Task class abstract away the operation's internals from my UI.
  • 4) Ability to abstract away the running of the operation - mocking, blah blah blah, future refactoring etc.

However - I don't seem to get ANY of these benefits.

  • 1) There is no abort functionality in Task - which strikes me as really odd.
  • 2) The only overload that I could get working with Task.Factory.FromAsync<> is the one shown below. This immediately begins execution of the webservice operation (as seen in Fiddler) and doesn't let me start the call later.
  • 3) Task doesn't implement INotifyPropertyChanged so i can't bind it to the UI.
  • 4) This one is kind of dead in the water given the other 3 benefits aren't happening :-(

Sooo.... Am i just wasting my time trying to get WCF generated proxies working with Tasks -- or am I missing something.

// WCF client
var client = new ShoppingCartClient();

// create task
var t = Task.Factory.FromAsync<GetOrderDetailsMsgOut>(
              client.BeginGetOrderDetails(new GetOrderDetailsMsgIn()
              {
                  OrderId = 12345
              },  null, null),    
              client.EndGetOrderDetails);

t.ContinueWith(x =>
{
    var order = x.Result.Order;
    // do something with order
});
abatishchev
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Simon_Weaver
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  • What do you see as the difference between the Abort functionality you're looking for, and the Cancel functionality present in Task? – John Saunders Sep 13 '10 at 02:57
  • @john - exactly the same - but there is no Cancel() method either. there IS an IsCancelled method, but no Cancel(). although I see now that i can cancel using a cancellation token http://msdn.microsoft.com/en-us/library/dd997364.aspx – Simon_Weaver Sep 13 '10 at 03:04
  • 1
    CancellationToken is the way to do a cancel. – John Saunders Sep 13 '10 at 03:05
  • @john - but when doing FromAsync i can't specify one. unless I create the task as an action, but then there's the threadpool concerns to worry about – Simon_Weaver Sep 13 '10 at 03:07

1 Answers1

1

As a part of the new Async capabilities Microsoft are planning for the next version of C#, they have released a CTP here, it is compatible with VS 2010 SP1.

A while back ago, I wrote a small blog post about one of the samples that is bundled with the CTP, about the TaskWsdlImportExtension.

abatishchev
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larsw
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