The DevExpress ASP.NET Callback (ASPxCallback) is a non-visual control that allows you to asynchronously transfer information from server to client, when this information is needed on the client side.
This demo initially displays short news headlines. Detailed news descriptions can be loaded dynamically, without refreshing the entire web page. This effect is achieved by using the client and server events available in the ASPxCallback component.
First, when a news headline is clicked, the client PerformCallback method of the ASPxCallback is called. This method is passed with an argument that contains the number of the corresponding news entry.
Next, the Callback event is raised on the server during server-side processing of the callback. In the event's handler, the required news description is obtained and assigned to the Result property of the event's argument.
Finally, when the response comes back to the client, the client CallbackComplete event of the ASPxCallback component is raised, allowing the resulting description text to be displayed within the page.