What is the correct way to implement server callbacks in ASP.net to update a control? I know all about AJAX and async client calls to server but what about this scenario:
You display a treeview (server control) with a list of items to the user. You have a server process running which checks a queue. When an item gets added to the queue it should update the tree control. How? Sounds easy. But seems ridiculously difficult in ASP.net.
The server cannot (generally) push content out to the client. Web browsers operate in a disconnected environment - in order to simulate "push" behavior you have to have the client periodically poll the server.
The exception to this is if you can use a technology like Silverlight or Flash, which can maintain persistent duplex connections to the server independent of the browser.
As far as I'm aware, most website that appear to dynamically "push" content out to the browser (eg. gmail, facebook chat, etc) are really polling periodically from the client.
