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Am I completely misunderstood ASP.Net AJAX (update panel)?

Perhaps I misunderstood how AJAX works. Can someone shed light on the following simplified scenario:

I have an asp.net web application. The page has a user control inside the update panel (without changing properties) and the script manager.

There is a label in the user control and on the form, both get their text in the DateTime.Now.ToStringload event. There is also a button that invokes a message in the user control.

When I click the button, I expect the shortcut inside the user control updates and one shortcut on the page will now be. So far so good.

However ... the page load event on the page is handled using isPostBack = True (which I did not expect), and it seems that everything that happens in the load event does not return to the client (as the label was not updated).

I did not expect the page load event (on the page containing the user control) to be raised and processed when the AJAX panel is updated, is this correct? or am i doing something wrong? I remember reading something about Page.IsCallback, but this is not true, so maybe this has nothing to do with it.

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4 answers

, AJAX per se, Microsoft AJAX- UpdatePanel, . UpdatePanel , , "post back" (ViewState POSTed , DOM , ) , , , HTML, UpdatePanel, AJAX. , .

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. , :

   if (ScriptManager.GetCurrent(this).IsInAsyncPostBack)
   {

   }
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http://forums.asp.net/p/1070297/1571597.aspx

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PostBack , .

UpdatePanel essentially does a full postback, but only the controls inside the update panel are updated on the client. Therefore, any controls outside the update panel will not be updated, even if you can change their value on the server.

You can use the property Page.IsPostBackto check if the page is loading initially or posting back. for example, just do something on the first page load:

if (!Page.IsPostBack)
{
    //doSomething
}
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