Making a List, Checking it Twice (Cool Ajax Sample App with ASP.NET 2.0 and Atlas)
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by Scott Guthrie
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Adding Atlas Support

So far, all of the steps we have followed work with the vanilla ASP.NET 2.0 and Visual Web Developer tool products – we haven’t used any Atlas features yet.

What we want to-do is to use Atlas to replace the built-in ASP.NET post-back model so that instead of refreshing the entire page when a post-back occurs, we use XMLHttp to only send back the regions of a page that have changed.  This enables us to make the page feel much more dynamic, perform faster, and obtain a much richer user-experience.

Step 14) Our first step to add Atlas support will be to add the <atlas:scriptmanager> server control to the page, and set its “EnablePartialRendering” attribute to “true”:

Figure 34

Step 15) We are then going to add an <atlas:updatepanel> control onto the page, and use it to wrap our GridView control and associated content:

Figure 35

This is now an “updatable” region within our page – which means that when a post-back event occurs, Atlas will intercept the event, and instead of refreshing the entire page it will use XMLHTTP to just send back partial updates from the server, and then dynamically repaint those portions of the page.

Try running the application again, and add a new item, then sort, filter, and edit items.  Notice how fast it feels – and the fact that the page wasn’t refreshed on each action. 

Step 16) When running the above app, you might have noticed when you added a new item to the list, the textbox value wasn’t cleared.  This is because the textbox lived outside of the <asp:updatepanel> we added above – and so wasn’t refreshed as part of our post-back call.

We could either move it to be inside the above <asp:updatepanel> or more optimally choose to add a new <asp:updatepanel> to the page that contains in.  This is more optimal because we will not update this panel every-trip to the server, but instead only when a declarative trigger that we’ll specify occurs (or alternatively if someone writes code on the server to explicitly trigger it). 

Figure 36

The above trigger means that this panel will only be refreshed only if the “add” button fired (or if we wrote code on the server to explicitly refresh it).  This means it will not fire in response to the drop-down filter changing, or to sorts, edits, updates, deletes within the GridView.

 

And now when we run our application again, it is ajax enabled, and allows us to dynamically add, remove, update, sort, page and filter our list items….

The full-blown sample I showed at the beginning does a few more cool things, but the walkthrough above captures the basic concepts from it.  As you can see, building one of these types of apps be done in minutes, doesn’t require much code at all (you only have to manually write 4 lines of code total), and enables you to start building Ajax applications with a fraction of the concept count from before.

Hope this helps -- and happy holidays,

Scott


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User Comments

Title: ERROR PROBLEM   
Name: tahir ASlam
Date: 2008-07-22 12:38:42 PM
Comment:
Sirr
I have tried this code as was needed for my project but am having a problem specifially in the line


Lists.ListsDataTable listData=listAdapter.GetBy(true);

Plus i did not understand what this statment would do even if it would ve not thrown any error so kindly would you be able to explain tht to me please>?>>
WOuld really appreciate your help
Thank you
Title: Anthem URL   
Name: Mathias
Date: 2006-08-08 4:58:44 AM
Comment:
Entering an URL didn't work...
http://www.anthemdotnet.com/
Title: I prefer Anthem   
Name: Mathias
Date: 2006-08-08 4:57:56 AM
Comment:
I prefer Anthem over Atlas... Check the site above.
Title: MR   
Name: Uday Shetty
Date: 2006-08-07 5:01:13 AM
Comment:
since many days i was wondering how to start ajax. In fact I had gone through many examples, but i was not successful. Finally I came across this example and i am thru.

I am very thankful to Mr Scott for this remarkable article. I wanted a srating point, which I found here. Now I can work on this technology & improve my knowledge on this.

Uday Shetty
India
Title: mr   
Name: chandra
Date: 2006-07-25 2:08:58 AM
Comment:
xie2 ni, thank you, arigato
Title: 100% worth to read - Excellent   
Name: Suchi
Date: 2006-07-08 1:47:45 AM
Comment:
Very good explanation. Its really helped me to understanding basic things. Thanks for your time.
Title: Excellent!   
Name: Nigel Bird (England)
Date: 2006-07-06 7:54:21 AM
Comment:
Just to say well done, I found this article very usefull. Thanks for taking the time to post it.
It has been apprecieated.... By the way it works just fine!

much regards
Title: it dosent work   
Name: Ramzy N.Ebeid
Date: 2006-07-03 11:08:52 AM
Comment:
dear sir
i make the sample as you say and it dosent work
and i dont know why ????
can you help me please
there is no errors






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