ASP.net Updatepanel运行缓慢（在所有浏览器中！）

Question

I have a very strange problem regarding my webpage. I use an SQL query to show the user possible searchs which he/she can check out.

The problem:

The SQL query and the string formatting took about 100-200ms at top, which result a string with a HTML format. But, on my browser (in IE, FireFox, Chrome, and tested on 5 different PC - the postback took about 2-3 SECONDS. The responded string is about 1-2kb, mostly less (sometimes it just couple hundred bytes!)

There is no content in the update panel, just the generated -s, so no big dropdown list or anything at all.

here is the snippet for the update panel:

<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <%= searchPanelPopUp %>
        </ContentTemplate>
    </asp:UpdatePanel>
</div>

And here is the c# code: http://pastebin.com/eBNTap4b

I do an async callback each time when the user change the text inside a textbox (there is a timer in the background, checking the changes each 500ms). If the text change, I do a callback

(JS code:)

function raiseAsyncPostback() {
    if (searchBoxContent != document.getElementById('txtWhere').value) {
        __doPostBack("<%= this.lbtnSearchPostBackRefresh.UniqueID %>", "");
    }
    searchBoxContent = document.getElementById('txtWhere').value;
}

The page itself load about 3-5 seconds (average is 3,5s).

Do maybe have anyone any idea why this is so slow? Or where I made a mistake?

Thank you!

Answer 1

I think, it's not problem of update panel. In your code behide, you are using many for inside for that is the problem. Please try other way. (p/s: sorry, i'm not enouht the epunation to add comment.)