Feel the need to clarify a few important sets of concepts

Thanks to all the love, many friends will encounter problems to Lao Zhao for questioning. However, in the process of reading a lot of friends, and in peacetime and other discussions, or in the garden articles often found some misuse of the concept of the situation. If there is no consensus on the concept, there will be many problems in work and communication. So while Lao Zhao has explained in other places (such as webcast or some articles), it still feels necessary to clarify some of the concepts and explain the differences and links between them. It is hoped that after clarifying these concepts, people will focus on the analysis of specific problems, rather than making communication a bottleneck.

In this article, I would like to clarify three sets of concepts, which are:

Ajax/ajax frame/ajax.net (Professional)/asp.net AJAX

Linq/linq to Sql/linq to XXX

Lambda expression/expression Tree/anonymous method

Ajax/ajax frame/ajax.net (Professional)/asp.net AJAX

This is the most confusing set of concepts I've ever seen. But the confusion between the four concepts has been exacerbated by the ASP.net Ajax framework that followed last year's Ajax boom and the endless Ajax framework. I can often see such a problem:

I do not know how to use AJAX technology in the UpdatePanel ...

When I invoke the Web service with the Ajax.NET framework ...

This is very typical of the concept of confusion, the above two words Ajax and ajax.net should use asp.net ajax replacement. On the difference between these concepts I "in simple asp.net AJAX" series Webcast many times to explain, but the results do not seem obvious. So I'm going to make another note here:

Ajax is the asynchronous JavaScript and XML abbreviation. This concept represents a technique that, when you say "I use AJAX technology in a project," only represents the asynchronous communication you make with the server side using the client XMLHttpRequest object. However, because the use of Ajax technology will often bring rich client effects, so the broad understanding of Ajax technology can also be considered as a kind of operation of the client DOM to bring rich results of the technology (this "broad" description is not accurate, we understand the meaning of old Zhao can be).

The AJAX framework is a set of code packages (libraries, etc) that help developers use AJAX technology. An AJAX framework is typically designed to encapsulate the use of XMLHttpRequest objects and provide a "shortcut" for manipulating DOM elements or implementing special effects. There are a number of mature Ajax frameworks that can be divided into "client-centric" and "server-specific technology" categories. The former excellent Representative has (in order): Prototype, JQuery, Mootools, YUI, Dojo and so on (the last two actually closer to a set of Client interface library, that is, "broad" AJAX framework), and the latter representative of the typical is both Ajax.NET and ASP . NET Ajax-and, of course, there are excellent AJAX frameworks for other server technologies, not to mention here.

Ajax.NET (Professional) is the famous Ajax framework on the ASP.net platform, born in February 2005 (although officially named Ajax.NET after two months), the author is Michael Schwarz. In October, Michael gave Ajax.NET a richer function (primarily in terms of security) and renamed it Ajax.NET Professional. Ajax. NET provides the most important (and only) function is to invoke the server-side method asynchronously, which is a very pure "data based" AJAX usage. This framework is a personal work, with support for. NET 1.1 and 2.0 versions, it is not part of Microsoft official, has now stopped updating.

asp.net Ajax's code name is "Atlas", which has undergone dramatic changes in the CTP to the beta version. asp.net Ajax includes controls such as UpdatePanel that make it very transparent to add AJAX effects to existing asp.net webforms applications. It also provides a way for clients to invoke Web services asynchronously, enabling developers to use AJAX techniques in a data-oriented manner. It is worth mentioning that the asp.net ajax "accessory" is quite rich. For example, the client part of ASP.net ajax named "Microsoft Ajax Library" is a pure client AJAX framework that provides a variety of basic components such as object-oriented type system, browser compatibility layer, asynchronous communication layer and so on; ASP.net AJAX open source expansion Pack " Ajax control Toolkit contains dozens of Ajax server-side controls that can be used directly, enabling developers to easily add rich client effects. At the same time, the official also provides "informal" expansion packs for ASP.net Ajax, where excellent controls such as history will also be included in future versions of the ASP.net AJAX framework. asp.net Ajax, an official AJAX framework, has now been integrated into ASP.net 3.5, so its version number has jumped from ASP.net Ajax 1.0 to asp.net Ajax 3.5. If you see these version numbers also please don't be confused, in fact ASP.net ajax 3.5 relative to ASP.net Ajax 1.0来 said just patched up some minor bugs, almost nothing changed.