why page load is called when an updatepanel is updated

Hi,

i have just observed that when a request is posted to server inside an updatepanel. then load method of page is called.

create a page with script manager and updatepanel. put a button inside the panel. add a msgbox in the load eventhandler of page.

now when u will click the button page load eventhandler would be executed. i was expecting that only the load event of update panel would be executed not the page one. because what ajax says is that whole page is not reloaded only the updatepanel is reloaded. does it mean that the ajax only helps to not activate the back button on browser but underlying it reloads the page in fact.

thanks

Hi i think you misunderstood something. what AJAX meant for is not exactly for asynchronous postbacks. This means that you cant execute two threads parallelly. But what it does is partial rendering. During an async postback all the usual events will be executed but only the contents inside the Update panel will be rendered.

hello.

well, what they're trying to say is that only the updatepanel contents will be updated during a partial postback. you can use the scriptmanager isinasyncpostback property to see if you're in a partial postback scenario:

http://asp.net/AJAX/Documentation/Live/mref/P_System_Web_UI_ScriptManager_IsInAsyncPostBack.aspx

rex_alias:

Hi i think you misunderstood something. what AJAX meant for is not exactly for asynchronous postbacks. This means that you cant execute two threads parallelly. But what it does is partial rendering. During an async postback all the usual events will be executed but only the contents inside the Update panel will be rendered.

I'm pretty sure that's exactly what AJAX is meant for.

And you can execute two threads parallelly.

Partial rendering isn't related to AJAX, you can have partial rendering without AJAX, and you can have AJAX without partial rendering, although it's implemented in the UpdatePanel and its implementation uses AJAX.

And yes, the whole life cycle of the page happens on the server, but only the relevant portions of the output are rendered into a xml based diff-gram, and sent to the client.

This is the nature of Update Panel. You can filter out the Regular Post Back with an Async by Checking the Page ScriptManager.IsInAsyncPostBack. Or if you do not want to page to be called then use the Client Centric Development Model which is calling the Web Service or Static Page Methods.

Why web robots cant request aspx pages in Ajax project ?

When Icreate aspx pages in Ajaxproject googlebot, yahoo-slurp and other crawlers can’t see these pages.

I’vecreated two test sites to show the problem:

Pagewithout Ajax:http://test.cky.pl/noajax/Default.aspx

Page with Ajax:http://test.cky.pl/ajax/Default.aspx

In browserI can see both of these pages. But when I try to saw what web robot can seewhen it requests my page (I was using this page and other tools (result wasthis same):http://www.smart-it-consulting.com/internet/google/googlebot-spoofer/index.htm

For Ajax page I was gettingerror massage:Invalid URL or serverdoes not respond, HTTP return code: 500

For normalaspx page everything is ok.

If someone couldshow me solution for this problem and could explain me why robots can’t requestAjax pages Iwould be very thankful.

Have you found a solution for this yet? I also noticed the same problem. If you point the W3C link validator at an AJAX site, it just says HTTP 500 internal server error. You get the same problem if you use an link checking package such as Xenu. If you view the page in your browser, it's fine.

This concerns me as I'm heavily involved in SEO - will Googlebot see the same and not index the site...

OK, found a workaround. Add this to Page.Init:

if (Request.Browser.Crawler ==true || Request.Browser.W3CDomVersion.ToString() !="1.0" || Request.Browser.Type.ToString().Contains("Opera")){ ScriptManager1.EnablePartialRendering =false;}else{ ScriptManager1.EnablePartialRendering =true;}

Thanks a lot, it's helps.

writing json back to client

I am making an xmlhttp request (using the scripts provided inAjax for Web Application Developersby Kris Hadlock) to get data from an aspx page. When I create a dataset and return xml with an xmldocument it works fine. I am using the following where dsreturn is the getXML of the dataset.

Dim xdocAs XmlDocument =New XmlDocument()

xdoc.LoadXml(dsreturn)

xdoc.Save(Response.OutputStream)

The problem is that I also want to return json. I have created a biz class to parse a dataset and return a json string. I know this works because I have used it in other web services. When I do this I get nothing. I think that my problem is how to return the json string in the response.outputstream. I am not sure how to do this. Just using response.write doesnt seem to work.

Thanx

Have you considered using page methods instead of doing it all by hand? They return JSON by default.