ASP.NET MVC async call a WCF service.

Question

Hi all. After complete of asynchronous call to WCF service I want set success message into session and show user the notification .

I tried use two ways for complete this operation.

1) Event Based Model.

client.GetDataCompleted += new EventHandler<GetDataCompletedEventArgs>(GetDataCompleted);
client.GetDataAsync(id, client);
private void GetDataCompleted(object obj, GetDataCompletedEventArgs e) 
{
   this.SetNotification(new Notification() { Message = e.Result, Type =    NotificationType.Success });
}

In MyOperationCompleted event i can set notification to HttpContext.Current.Session, but I must waiting before this operation will completed and can't navigate to others pages.

2) IAsyncResult Model. In this way I can navigate to other pages and make asynchronous calls to wcf service, but in GetDataCallback method can't set notification, becouse session = null.

client.BeginGetData(id, GetDataCallback, client);
private void GetDataCallback(IAsyncResult ar)
{
    string name = ((ServiceReference1.Service1Client)ar.AsyncState).EndGetData(ar);
    this.SetNotification(new Notification() { Message = name, Type = NotificationType.Success });
}

"Generate asynchronous operations" in service reference enabled.

Please help me with this trouble. Thanks.

Answer 1

I'm no wcf expert, but what I've found to work is wrapping your call to the Async version of your method in ThreadPool.QueueUserWorkItem. Without this, I had same blocking issue. So this seems to free up the main thread in your asp mvc to move on while another worker thread waits for the callback.

Also, I used AsyncController, although that alone was not enough without the worker thread.

See this: http://msdn.microsoft.com/en-us/library/ee728598.aspx

I used this as a guide, but still needed the ThreadPool.

Cheers