Page 58 - DCAP312_WEB_TECHNOLOGIES_II

Web Technologies-II

Notes
There are potential security risks when using and developing custom ASP.
NET controls.

Bringing WinForms Controls to the Web with AJAX

stablished in 2000, Atalasoft is a provider of a high-performance, standards-compliant
.NET Framework imaging libraries targeted towards authors of document processing
Eand management systems and photographic imaging. Atalasoft offers unparalleled
ease of integration through CLR compliant objects, logically laid out object hierarchies, rock
solid implementation, and first rate support.
In 2003, Atalasoft decided to make web versions of their WinForms imaging controls. The
main issue in the port of the controls to the web was how to get the same interactivity in a web
control that you could get in WinForm control. Here is a short list of the major requirements:
Key Web Image Viewer Requirements

• Cross-platform and cross-browser
• Interactivity similar to what you get with the WinForms controls:

 Scroll bars when a large image was shown in a small viewport
 Ability to load parts of the image on demand
 Ability to pan, zoom, and select with mouse gestures
• Tight integration with HTML, CSS and JavaScript on the client and ASP.NET on the
server
• No special security settings required

• No plug-ins or anything to install or approve
• Technology could be used for future controls
 The Web Thumbnail Viewer (released in 2006) required lazy loaded thumbnails and
full integration with the Image Viewer
o The Web Annotation Viewer (released in 2007) required the ability to create, edit,
move and resize annotations in the browser
For this project, we chose to use the techniques that would later be called AJAX. The term
was coined in 2005 to describe the general technique of using JavaScript to contact a server
asynchronously whenever the user needs a server update and using the result of that
communication to change the DOM by generating HTML dynamically with JavaScript. The
most famous example is Google Maps, but the browser features that enable what we call
AJAX were introduced into Internet Explorer in 2000 to implement Outlook Web Access. By
the time Atalasoft started, these features were implemented in all major browsers.
<embedsrc=“http://www.youtube.com/v/ZCit_ZEUEjc”width=“425”height=“350”
type=“application/x-shockwave-flash” wmode= “transparent” /></embed />

AJAX is just one way to get interactivity in a browser. The general term for applications
like this at the time were Rich Internet Applications (RIA) and that term is still used to
encompass the wide range of technologies that can implement a desktop-like feel in a web
Contd...

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