Sunday, September 17, 2006

ATLAS Data Applications and Down-level support

I must confess that aslthough I am excited by the whole AJAX phenonenon, and the rich client experience that it provides for the majority of desktop browsers, I sometimes feel concerned about those that for whatever reason aren't able to experience the full beauty of a javascript enabled client. There are two main groups of people that are missing out

  1. Users with certain accessibility needs (often browsers and tools designed for people with disabilities have to run without the javascript support we usually take for granted) and
  2. PDA users (This is an increasing market, and to date only 1 browser has implemented any kind of javascript engine for devices, .

So I am always looking for ways to enhance these users experience.

My AJAX toolkit of choice (more through accident than intent) is ATLAS (Microsofts library). ATLAS contains a data enabled control called a ListView which is quite powerful. It works on a client side JavaScript based object model and the best way to get to know it is to read the data section of the ATAS documentation.


So the idea is, get a funky ATLAS based website working, and then attempt to create a version of that website as quickly as possible that can be used by people who can't (or won't) use javascript (similar to what google does with gmail).


I decided to make the sample as simple as possible without loosing anything along the way. I decided to create a Shopping List, that simply contains a quantity (double) and an item (string).

The bueaty of the ListView in ATLAS is that it can use the System.Component model similar to other databinding in ASP.Net 2.0. So the first step in creating a webservice that derives from Microsoft.Web.DataService (refer to the ATLAS documentation for more details).  I then create my ListView templates and hook it all up using XML-Script, and pretty it upwith any CSS I may care to add. The result can be seen here (Please forgive me I'm not a graphic artist). Once this is done, I needed to create a Non-ATLAS version of the same page. As my webservice already uses the System.Component model, it was extremely easly to add a GridView control, select an Object DataSource and wire it up, and away it goes. All in all it took me abou 10 minutes to create the NON-Atlas page. It would have taken me another 2 minutes to enable things like edit/delete, but for the moment I wanted to keep it the same as the ATLAS version, this may be the subject of a future post. The only significant difference between the two pages is the presence of a select link on the NON-ATLAS enabled version whereas the ATLAS version manages the select operation simply by handling the mouse click.


Once you have these two pages it is simply a matter of choosing your favourite way to direct users with different broswser capabilities to the correct site.

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