RadAjax for ASP.NET

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Glossary Item Box

The telerik AJAX framework allows developers to AJAX-enable any new or existing ASP.NET application without writing a single line of code. No previous knowledge of the AJAX development technique is needed, which makes Telerik RadAjax a prefect solution even for beginners.

In the core of the Telerik RadAjax framework is a patent-pending technology, which can make selected controls on the page perform AJAX callbacks instead of traditional postbacks. The whole AJAX behavior of the page is controlled through a single control, called Telerik AJAX Manager, which is configured completely in design-time through a single dialog.

Benefits of the Telerik AJAX framework

  • AJAX-enable any existing or new application, regardless of its level of complexity - most AJAX-enabling products offer just limited AJAX capabilities, allowing you to merely load/update a control with a callback. Those solutions, however, do not send form values to the server for processing, or do not preserve the ASP.NET page lifecycle. As a result you can implement only a limited number of scenarios. The Telerik RadAjax framework on the other hand can cover any scenario that can be implemented with the traditional postback mechanism. Resultingly, you can build very sophisticated applications, similar to Outlook Web Access or the Telerik HelpDesk sample
  • Don't have to know in details how AJAX works - you don't have to know AJAX in order to use AJAX. The Telerik framework encapsulates the complexity and intricate client-side scripting in a convenient component model. The postback behavior of the selected elements is automatically replaced with AJAX callbacks and the typical challenges of AJAX development are handled internally. So there is less to learn and less to worry about.
  • Don't have to make any modification to your application - a key disadvantage of other AJAX frameworks is the fact that you need to turn you application inside out and make major modifications in order to make it work with AJAX. You typically have to place Callback Panels around areas that need to be updated, set triggers, and manually invoke AJAX requests. In contrast, thanks to the patent pending Click-and-Go™ technology of Telerik RadAjax you only have to drag-and-drop the AJAX Manager on the page, tick the respective checkboxes in the dialog, and hit F5. You application is now AJAX-enabled. (Watch a video)


  • Don't have to write a single line of code (JavaScript or server-side) - the Telerik RadAjax framework offers a completely codeless approach for AJAX-enabling existing or new web applications. Postback requests of selected elements are automatically replaced with AJAX callbacks so that you don't have to attach custom JavaScript functions to page elements and invoke AJAX requests manually. Furthermore, the elements that need to be updated after the server response are updated automatically by the Telerik RadAjax client-side engine.


Controls comprising the Telerik RadAjax framework


The the Telerik RadAjax framework features two main controls - the AJAX Manager and the AJAX Panel. Both of them include the Telerik server- and client-side AJAX engine and may be used individually.

  • AJAX Manager - enables selected control(s) on the page to initiate AJAX requests instead of postbacks, and update other control(s) on the page. All AJAX relations (which control updates which) are defined through one centralized place - the convenient dialog of the AJAX Manager (in Visual Studio design mode).
    The AJAX Manager can handle even the most complex scenarios and offers a number of advantages compared to other solutions.


  • AJAX Panel - this control is suitable for simpler scenarios. It represents a container that AJAX-enables all controls placed inside. As a result those controls start making AJAX callbacks instead of postbacks. 
    The AJAX Panel only affects the elements placed inside it. For example, if you put a DataGrid control or the Telerik Telerik RadGrid inside an AJAX panel, the grid will start performing AJAX requests instead of postback for paging, sorting, editing, etc. However, the grid will not be able to update other elements on the page, which are outside the AJAX Panel. Such scenarios can be easily handled by the AJAX Manager. To read more about the difference between the AJAX Manager and the AJAX panel and the suggested use cases, please read section "AJAX Controls -> Panel vs. Manager".


In addition, the Telerik RadAjax framework includes two auxiliary controls:

  • Loading Panel - this is a control that is shown during the AJAX request and serves a a progress indicator.
  • AJAX Timer - this time-bound control ticks and makes one or more postbacks at a predefined interval. This control should be used together with AJAX Panel or AJAX Manager in order to perform AJAX requests.


Features of the Telerik AJAX framework

  • Works with any standard ASP.NET controls and most 3rd party controls (including Telerik RadControls for ASP.NET) - the Telerik RadAjax patent-pending technology can AJAX enable any of the standard controls shipped with Visual Studio 2003 and 2005 and well as all of the controls included in the Telerik suite for ASP.NET. Most 3rd party controls are also supported, however due to some specifics of certain implementations full compatibility is impossible.
  • Support for .NET 1.x and 2.0 - Telerik RadAjax uses a proprietary AJAX engine that works both on the 1.x and 2.0 versions of the .NET framework.
  • Preservation of the page life-cycle - Telerik RadAjax does not break the normal page life-cycle, which guarantees the proper functioning of your applications. Actually, the AJAX-enabled controls don't really know that they are working in AJAX mode rather than postback mode.
  • Proper handling of the ASP.NET ViewState and EventValidation - unlike other AJAX Frameworks Telerik RadAjax updates the ViewState of the page after the AJAX request in order to keep it in a consistent state regardless of the type of the request that has been made (AJAX callback or postback).
  • Persistence of form values - all form values are sent to the server for processing during the AJAX request and are persisted between AJAX requests. All form controls can be referenced in the code-behind as if a postback occurred. This feature guarantees that your AJAX-enabled applications will not be limited to mere rendering of controls with AJAX, but can cover even the most complex scenario.
  • Persistence of JavaScript code - Telerik RadAjax controls re-initialize JavaScript code after an AJAX request has been performed. This behavior is very important when working with third party that feature rich client-side functionality like the Telerik RadControls for ASP.NET for ASP.NET. The proper functioning of such controls will not be affected when they are AJAX-enabled with Telerik RadAjax.
  • Support for ASP.NET Client Validation - Telerik RadAjax controls fully support server- and client-side validation implemented with the standard ASP.NET validation controls.
  • Search-engine optimization - the Telerik RadAjax controls automatically detect and handle the web crawlers (search engines) and render alternative content, suitable for indexing.

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