This sample illustrates use of AJAX-based callbacks implemented by DevExpress MVC Navigation Bar.
The MVC NavBar supports AJAX with the ability to load a group's content from the server via a callback when the group is expanded. This approach allows the NavBar to avoid the initial transfer of all group data to the client, thus improving page load times.
In order to activate use of callbacks, the NavBar's CallbackRouteValues property should contain the path to an action that handles a callback request. The best way to handle such callbacks is to use a partial view that only contains a NavBar.
In this sample, we momentarily pause callback processing on the server side, so that the Loading Panel is visible during processing.