Comments on: Are you making these 3 common ASP.NET AJAX mistakes?

By: Robert Mayer

Robert Mayer — Wed, 17 Feb 2010 17:26:42 +0000

Thank you so much! That bit about using __EVENTTARGET to determine which UpdatePanel triggered the partial page postback solved a nagging problem in my app!

By: The Seven Sins of DotNetNuke Module Developers | TechBubble

The Seven Sins of DotNetNuke Module Developers | TechBubble — Sat, 30 Jan 2010 00:29:32 +0000

[...] ASP.NET developers implement AJAX functionality. For every AJAX request, UpdatePanel causes the entire page life-cycle to be repeated on the server. As a result, a module that has lots of AJAX functionality implemented using UpdatePanel is going [...]

By: Torbjörn

Torbjörn — Tue, 29 Dec 2009 10:25:26 +0000

Very nice article, just what I was looking for!

By: Balaji Birajdar

Balaji Birajdar — Wed, 25 Nov 2009 11:37:13 +0000

Great insight. I admit , that I was making the same mistakes :(. But now I will not …. :)

By: Dave Ward

Dave Ward — Wed, 26 Aug 2009 15:28:13 +0000

I’ve run into that myself, and to be perfectly honest I’m not completely clear on why the $ delimited UniqueID comes back sometimes, but not usually. I think it has to do with controls being inside ITemplate containers, like content pages, GridView templates, etc.

If you find a definitive answer, let me know. I’ll add a note to that section of the post.

By: Nathan

Nathan — Wed, 19 Aug 2009 17:15:47 +0000

I completely admit that I did not understand the page lifecycle, and never realized how important it is until messing with some ajax. I have done a couple things before and used a check for Page.IsPostBack to control things before. Did not know the order of lifecycle events though. So thank you for the quick intro in my ignorance.

That said, I used your code sample to check to see which updatepanel is requesting postback. I found that my updatepanels are not the __EVENTTARGET, but the trigger, so:

Request["__EVENTTARGET"] != UpdatePanel1.ClientID

but:

Request["__EVENTTARGET"] == DropDownList.ClientID

and really, ClientID would not equal the Request either as Request["__EVENTTARGET"] returns this: “ctl00$Content$DropDownList”
and my DropDownList.ClientID returns this:
“ctl00_Content_DropDownList”

So reading the comments here, I see UniqueID is supposed to be interchangeable. I replaced ClientID with UniqueID and I get correct returns.

Any reason why my code would be causing the differences here? Note: I do the check for this in the Page_Load event. Although I did try in the UpdatePanel’s PreRender event and the same data was being returned.

By: Dave Ward

Dave Ward — Tue, 04 Aug 2009 15:44:29 +0000

In the paging scenario, you’ll need to somehow store those fields (e.g. session state or database) and use history points for each page.

By: sujit

sujit — Tue, 04 Aug 2009 07:23:51 +0000

But as i go on adding the history points for each control on the page one after another, the addhistorypoint had added the point for last selected control only. So when i select multiple controls, the add history point restores the state only for the last selected control.

By: Dave Ward

Dave Ward — Fri, 31 Jul 2009 18:58:44 +0000

ASP.NET AJAX has a feature to provide browser history support. Check out ScriptManager.AddHistoryPoint for an entry point into that functionality.

By: sujit

sujit — Fri, 24 Jul 2009 10:43:00 +0000

i have a different kind of problem. When my application redirects to another page and later when i click back button on my browser all the data on my previous page gets cleared which was on the update panel. Where exactly am i missing. Please guide

By: Are you making these 3 common ASP.NET AJAX mistakes? « Evil Science

Are you making these 3 common ASP.NET AJAX mistakes? « Evil Science — Sat, 27 Jun 2009 22:30:39 +0000

[...] the full article here, which is featured on the site [...]

By: Sıfırdan AJAX öğrenebileceğiniz 20 kaynak

Sıfırdan AJAX öğrenebileceğiniz 20 kaynak — Sat, 06 Jun 2009 10:20:01 +0000

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By: Dave Ward

Dave Ward — Tue, 21 Apr 2009 03:52:08 +0000

That’s not the behavior I would expect either.

By: Renu

Renu — Mon, 20 Apr 2009 23:33:27 +0000

I have any update panel set to conditional updateMode with a trigger against a dropdown out side the panel and childrenastriggers as false. I load user controls dynamically on this panel.The user control has one drop down list with autopost back set to true.
On selecting value in the user control drop down my script manager isAsynPostback still comes true. Should’nt this is false as i have childrenastriggers set to false?

By: 用__doPostBack在client端更新UpdatePanel | Horn Network

用__doPostBack在client端更新UpdatePanel | Horn Network — Sun, 29 Mar 2009 14:02:32 +0000

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