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Callbacks (AJAX)

Move the dock panel between zones to see the feature in action.

The DevExpress ASP.NET Dock Panel (ASPxDockPanel) has the capability to load panel content on demand via callbacks. Several content loading modes are available using the following settings of the LoadContentViaCallback property:

  • None - The content is always (initially) rendered inside a dock panel (the default behavior).
  • OnPageLoad - Panel content loading starts immediately after the entire page has been loaded.
  • OnFirstShow - Panel content loading starts when a dock panel is invoked for the first time.
  • OnDock - Panel content loading starts each time a panel is docked to a dock zone.
  • OnDockStateChange - Panel content loading starts each time a panel's dock state is changed (i.e., a docked panel becomes floating or a float panel docks to a zone).
  • OnFloating - Panel content loading starts each time a panel is made floating.

Using a postponed load of panel content, you can improve the response time of your web page on its initial load. You can also update the content of a dock panel programmatically on demand.

Note that in this example, callback processing is intentionally paused on the server side for half a second in order to make the Loading Panel visible during this time.

Local Copy of this Demo
To inspect the source code for this demo on your machine, you must first install our components via the DevExpress Component Installer.
You can open a local copy of this online demo directly from this webpage (if using v20.2.8, 21.1.4 or higher).
Open CS Solution
Open VB Solution
The source code files for this demo are installed (by default) in the following directories:
\Users\Public\Documents\DevExpress Demos XX.X\Components\ASP.NET\CS\ASPxDockAndPopupsDemos
\Users\Public\Documents\DevExpress Demos XX.X\Components\ASP.NET\VB\ASPxDockAndPopupsDemos