While web technology has continued to advance for both developers and the users of web applications, certain fundamental limitations still exist. Data that is posted from a browser to the server still requires a page refresh to display new information. This refresh, with associated communication and rendering delays, continues to be a factor that limits the effectiveness of sophisticated Web applications.
LiveControls can be used in a wide variety of applications that require a quick "round trip" to the server without the delay and refresh that is normal for a post. Financial market applications can now present instant news and rate changes without refreshing the page. Sports applications can update statistics and scores without user interaction or screen flicker. Slideshow applications can be server driven with changing images. Polling application can show real-time poll results rather than a snapshot of results. Inventory control and commerce applications can benefit by having screens that reflect quantity or pricing changes without refreshing the page, and customers can benefit from a shopping cart that always shows the latest prices and inventory based on user choices. Other types of applications include web-based CRM systems that change screens without a refresh or displays new information as it changes at the server. The potential uses of this technology are inspiring!
Smart Navigation. Microsoft included this technology in .NET version 1. A traditional POST is used to capture a new page in an invisible IFrame, then IE attempts to intelligently update form elements without refreshing the entire page. This feature has a bad reputation, requires the use of IE, and still has the server render the entire page.
|Support for callback technology
||Easy as dragging and dropping a control on a WebForm
||$499 Developer License
|Support for Cascading Style Sheets
||Can be set as a property on every major object
||None except when creating custom callbacks using LiveCallback control
||Increases as complexity of requirements grows
||Completely supported between callbacks
||Native ASP.NET Web Controls
||Requires manual implementation in code-behind
|Client-side object manipulation
||Automatic by using server-side model
||Support for blocking and non-blocking
|Custom callback capability
||LiveCallback wires up server-side functions
||Compatible with IE 5.0 +, IE 5 Mac, Mozilla 1.3+, Mozilla 1.3+ Mac, Galeon, Konqueror and Opera 5+
||Must know the proper object and technique for every browser
||Limited to versions of IE and Netscape that support XMLHttpRequest
|Windows-like look and feel
||Built-in with mouse, click, and key events
||ASP.NET Web Controls
||Manual use of the XMLHttpRequest object
|Visual Studio Integration
||Naturally integrates as an ASP.NET Web Control
|Bandwidth Saving Features
||Ability to control server-side persistence
||Ships with seven ASP.NET C#, VB.NET samples
||Comprehensive help integrated with the Visual Studio IDE using the Help 2.0 engine with full dynamic help and tutorials.