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 Sys.WebForms.PageRequestManager only with UpdatePanel?

Why do I only get access to Sys.WebForms.PageRequestManager if I have an updatepanel in my page? I have some really good uses for this method, but right now I only get access to the object if I include an UpdatePanel in the page.

If I want to include this when I have my control in the page, what is the parameters needed to extract it from the resources using Page.ClientScript.GetWebResourceUrl ?

In the RTM version (due out by the end of this month), Sys.WebForms.PageRequestManager will be available even if you don't have an UpdatePanel on the page. In the mean time, I recommend just putting an empty one on the page: <asp:UpdatePanel runat="server" />.

Perfect !

Wow - glad I found this post, that was going to be a long, painful and probably fruitless debug session otherwise. Thanks for that!

PS. Anyone know *why* this is the case?

Will calling .click() fire an updatepanel Trigger?

This might seem a bit silly but...

Basically, I have a javascript function which calls the .click() method of a button, this button resides outside of any UpdatePanels

This button is also set as a trigger for one of my UpdatePanel controls.

My problem is, the button click runs fine, the server side click event fires ok and rebinds some data for a GridView which is inside the UpdatePanel, but the UpdatePanel does not update its contents.

Do you have to physically click the button with your mouse to cause the Trigger? Or should the programmatic javascript call to click() work?

No will not cause it trigger, you need a postback for that, not a javascript call

You cantrigger an UpdatePanel refresh from the client side, using __doPostBack().

Hi

The programmatic javascript call to click() should work, you must do something wrong.

Look this sample:

<%@. Page Language="C#" %>

<%@. Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
<link href="http://links.10026.com/?link=StyleSheet.css" mce_href="StyleSheet.css" rel="stylesheet" type="text/css" />

<script type="text/javascript">
var styleToSelect;
function onOk() {
$get('Paragraph1').className = styleToSelect;
}
</script>

</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<p id="Paragraph1">
GetContentFillerTextGetContentFillerTextGetContentFillerTextGetContentFillerText</p>
<br />
<ajaxToolkit:Accordion ID="Accordion1" runat="server" ContentCssClass="grey" FadeTransitions="false"
FramesPerSecond="25" TransitionDuration="250" HeaderCssClass="dimgreen" EnableViewState="true">
<Panes>
<ajaxToolkit:AccordionPane runat="server" ID="PaneOne">
<Header>
AccordionPane0
</Header>
<Content>
<a href="http://links.10026.com/?link=javascript:return false" onclick="javascript: LinkButton1.click()">Click here to change
the paragraph style</a>
</Content>
</ajaxToolkit:AccordionPane>
</Panes>
</ajaxToolkit:Accordion>
<div style="visibility: hidden">
<asp:LinkButton ID="LinkButton1" runat="server" Text="Click here to change the paragraph style" /></div>
<asp:Panel ID="Panel1" runat="server" Style="display: none" CssClass="modalPopup">
<asp:Panel ID="Panel3" runat="server" Style="cursor: move; background-color: #DDDDDD;
border: solid 1px Gray; color: Black">
<div>
<p>
Choose the paragraph style you would like:</p>
</div>
</asp:Panel>
<div>
<p>
<input type="radio" name="Radio" id="RadioA" checked="checked" onclick="styleToSelect = 'sampleStyleA';" />
<label for="RadioA" class="sampleStyleA" style="padding: 3px;">
Sample paragraph text</label>
</p>
<p>
<input type="radio" name="Radio" id="RadioB" onclick="styleToSelect = 'sampleStyleB';" />
<label for="RadioB" class="sampleStyleB" style="padding: 3px;">
Sample paragraph text</label>
</p>
<p>
<input type="radio" name="Radio" id="RadioC" onclick="styleToSelect = 'sampleStyleC';" />
<label for="RadioC" class="sampleStyleC" style="padding: 3px;">
Sample paragraph text</label>
</p>
<p>
<input type="radio" name="Radio" id="RadioD" onclick="styleToSelect = 'sampleStyleD';" />
<label for="RadioD" class="sampleStyleD" style="padding: 3px;">
Sample paragraph text</label>
</p>
<p style="text-align: center;">
<asp:Button ID="OkButton" runat="server" Text="OK" />
<asp:Button ID="CancelButton" runat="server" Text="Cancel" />
</p>
</div>
</asp:Panel>
<ajaxToolkit:ModalPopupExtender ID="ModalPopupExtender" runat="server"TargetControlID="LinkButton1"
PopupControlID="Panel1" BackgroundCssClass="modalBackground" OkControlID="OkButton"
OnOkScript="onOk()" CancelControlID="CancelButton" DropShadow="true" PopupDragHandleControlID="Panel3" />
</div>
</form>
</body>
</html>

Thanks

window.onload alternative

I believe there is a method in the Microsoft AJAX framework that is part of the client side (javascript). That allows multiple onload events to be registered easily.

I can't find it in the documentation though. Can someone point me in the right direction?

Thanks

You can use Sys.Application to register/deregister load and unload handlers.

would like a detailed explanation of dynamic populate page method

hey everyone

could someone explain to me what the bonuses are of using dynamic populate page method
(and therefore stuff like dynamiccontrolID and dynamicservicemethod)

as opposed to just executing a sqlcommand inside an eventhandler
when the user clicks a linkbutton

i know theres probably a really good reason
its just pretty muddy to me right now

thanks

Dynamic populate happens via a web service call and does not incur the overhead of a postback with full page lifecycle. The downside is that you can't create new server controls via a dynamic populate that are accessible in the underlying page.

DynamicServicePath: path to the web service