Asp.net+atlas Create a client Web application

Abstract This article introduces the Atlas framework and explores its client and server-side library and its programming model. In addition, a sample Web application that supports the Atlas feature is analyzed in detail.

I. Development environment DESCRIPTION

The information provided in this article applies to the following technologies: asp.net 2.0,asp.net Atlas ctp,visual Studio Professional 2005 and Visual Web Developer 2005.

Ii. Introduction

Atlas is a code name for a framework that extends asp.net for the development of client Web applications. While providing a set of client and server-side classes to create Cross-browser-compliant AJAX-style applications, the framework introduces other features such as bridging technology, Gadget, a JavaScript declarative scripting model, and extensions.

This article will introduce the Atlas framework and explore its client and server-side libraries and their programming models. In addition, a sample Web application that supports the Atlas feature is analyzed in detail.

Three, client-based and server-side Web applications

Web application development is now focused on HTTP clients (browsers) and server development. asp.net Web applications are server-based (run on this host), so a full postback is required for each event that is fired by a server control on the client. Such a scenario can be described in Figure 1.

Figure 1. HTTP feedback for a asp.net web application

Web applications are run only on the server side, with little or no client processing, and performance degradation is not required. However, its drawbacks can easily be found in a asp.net Web application: A blinking, paused, unresponsive, and relatively poor UI, or a busy line due to data postback and server overload.

Addressing these performance hurdles in the ASP.net application means that some load processing must be moved to the client and leveraging the technology provided by the client platform. The client platform can be scripted, and JavaScript is a standard object-oriented programming language for this task.

So what do these client platform technologies refer to above? These client platforms (browsers) provide the following technologies:

· Document Object Model: a standardized set of language-independent sets of objects that allow developers to dynamically control the structure, content, and style of HTML documents.

· Dynamic Hypertext Markup Language object model: A browser vendor-specific collection of features that can be used as an extension of the DOM. Data binding, UI effects (such as filters and transitions), HTML element behavior, and events are some of the features provided within the object model.

· XMLHttpRequest object: It allows retrieving and submitting XML data over HTTP without requiring a complete feedback or regeneration of the entire Web document.

· A JavaScript interpreter: contained in all Web browsers, which handles commands written in JavaScript. JScript is a Microsoft version of JavaScript, which was originally created by Netscape. Both versions follow the ECMAScript standard-vendor-neutral, cross-platform, general-purpose scripting language.

These technologies, together known as Ajax, are meant to be asynchronous Javascript+xml, and Atlas is a framework for creating Web applications that leverage these technologies. Figure 2 below shows a asp.net web application that supports the Atlas technology.

Figure 2. HTTP request and response a client-based asp.net Web application that supports the Atlas technology