ASP.NET AJAX Callback Control

What Is KCallback.NET Control?

The KCallback.NET control is the most powerful, robust, callback control available in the market today for ASP.NET with AJAX support. Written in 100% managed C# code, KCallback.NET provides callback functionality in your Web applications. The KCallback.NET control allows developers to AJAX-enable any ASP.NET application by writing a few lines of code. It allows you to update page content without postback and loss of scroll position!


  • AJAX: AJAX (Asynchronous JavaScript And XML) enables your Web applications to increase interactivity, speed, and usability.
  • ASP.NET Standard controls & 3rd Party controls: KCallback.NET can AJAX enable standard ASP.NET controls and 3rd party controls.
  • Save State: You can save the state of all the form controls during a callback request by setting the SaveState property to true.
  • Callback Result: Returns a callback result to a client-side function instead of rendering.
  • Callback Error: Return a callback error to a client-side function for exception handling.
  • Override Output: Overrides the callback contents both on the server side and client side.
  • Loading Display: Displays an HTML block while processing the callback request.
  • Disable Controls During Callback: KCallback.NET automatically can disable selected controls during callback
  • Enable Caching: Cache callback arguments and results on the client-side to improve performance.
  • MultiArgument: You can pass multiple arguments into the Callback event handler and process them on the server side.
  • Auto Callback: Initiate callbacks automatically at specified intervals in milliseconds.
  • User Control: You can insert the KCallback.NET control into a user control. You can run two instances of the same user control on the same page.
  • Client-Side API: KCallback.NET supports a client side function to handle the result and error for the callback response from the server.
  • Server-Side API: Processes callback requests in the Callback event handler.
  • Before and After execute client side event handler: This allows you to alter/cancel the callback before and after executing a client-side event.
  • XHTML Compliance: XHTML 1.0 Transitional compliant.


In the core of the control, KCallback.NET can make selected controls on the page, performing AJAX callbacks instead of traditional postbacks. The whole AJAX behavior of the page is controlled through a single control, called the KCallback.NET control.

The KCallback.NET control uses AJAX (Asynchronous JavaScript and XML) technology to communicate with server-side functions to update portions of the client-side page without reloading the whole page. With the KCallback.NET control, complex content can be updated from the server “in live” and the end user has a smooth browsing experience. It is extremely useful when heavy server-side processing is needed; for example, accessing a database or contacting a Web service. In addition, nothing is used except common DHTML/remote scripting techniques. There is no use of Flash, Java, or other plug-in technology.

The following list outlines the benefits of the KCallback.NET control.

  • No need to learn how AJAX works: You don’t have to know AJAX to use AJAX. The postback behavior of the selected elements is replaced automatically with AJAX callbacks and the typical challenges of AJAX development are handled internally. So, there is less to learn and less to worry about.
  • Improved User Experience: KCallback.NET handles page update with AJAX-based callback requests, instead of complete postbacks. As a result, there is no loss of scroll position; only the relevant elements are updated, just like in Windows applications. This leads to smoother interface transitions and superior user experience. The KCallback.NET can handle even the most complex scenarios and offers a number of advantages compared to other solutions.
  • No Need to Write Complex JavaScript: KCallback.NET eliminates the need for writing the complex JavaScript required for updating interface elements of AJAX-enabled ASP.NET applications.
  • Design-time Support: Due to the fact that KCallback.NET can update standard ASP.NET controls without using callback wrappers, development of AJAX-enabled ASP.NET applications is quite similar to any standard ASP.NET application; this makes design and deployment a breeze for you and your team.
  • No Need for Callback Wrappers: A major advantage of the KCallback.NET control is that it can update the standard ASP.NET controls without using callback wrappers/placeholders, which define the parts of the page that have to be updated. The KCallback.NET control automatically detects all page modifications and updates the relevant controls. This significantly minimizes the number of changes you have to make to existing applications to implement the AJAX functionality.
  • Cross-Browser Support: KCallback.NET works on all browsers that support XmlHttpRequest (IE5+, NS7+, Firefox 1.0+, Mozilla 1.0+, and Opera 8+).

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