Want To Validate Username Availability Asynchronously?
While I was reading my feed aggregator at the weekend, I was paid attention to the recent post from Encosia because of its title. Validating a username asynchronously would be a great functionality in almost every types of online registration scenarios. Right after reading the post, I downloaded the binary file from CodePlex and created a very simple demo in about half an hour. That was really easy to implement.
Implementation
Before starting to code, be sure that the dll that is downloaded from CodePlex is in the Bin directory:

My sample (yes, very simple) registration form is:

As it can be seen, the trick is with the ServicePath and ServiceMethod attributes. ServicePath is the path to the webservice housing the ServiceMethod, and ServiceMethod is the method checking the availability of a username. My sample (yes, again very simple) webservice is:

Details of other attributes of the control can be read via its Discussions page at CodePlex.
Finally, here is how the form looks like after all these implemenations:

Download
You can download this sample registration form from here.
Issue Tracker
I would encourage to write your comments to here if you face any issues about the control.