DropDownList with many entries is slow when EnablePartialRendering = true, but it is fast

Hello together,

I have a big performance problem when I use a DropDownList in an UpdatePanel. This is my code:

ASPX-Page:

<asp:ScriptManager ID="smMain" runat="server" EnablePartialRendering="true">
</asp:ScriptManager>
<asp:UpdatePanel ID="upPartial" runat="server">
<ContentTemplate>
<asp:DropDownList ID="ddlList" runat="server" />
<asp:Button ID="btnPostBack" runat="server" Text="PostBack" />
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdateProgress ID="progress" runat="server" DisplayAfter="0">
<ProgressTemplate>
Wait Please...
</ProgressTemplate>
</asp:UpdateProgress>

CodeBehind:

protected void Page_Load(object sender, EventArgs e)
{
for (int i = 0; i < 10000; i++)
{
((DropDownList)this.upPartial.FindControl("ddlList")).Items.Add(new ListItem("Value " + i.ToString(), i.ToString()));
}
}

When I click the button on this page it takes about 1 minute to complete the partial postback. But it is a simple postback with no other code to execute. When I set EnablePartialRendering = false in the ScriptManager the same postback executes in about 1 second.

Can somebody tell me what is the problem with the partial postpack?

Thanks and best regards

Gunther

Hi Gunther,

Well this is an issue that i have seen before on this forum. As far as i know you can't fix this when you take a look at the Ajax framwork. I think that a dropdownlist with 10000 rows isn't a very user friendly dropdownlist. Why are you putting so much items in 1 dropdownlist? Isn't possible to filter some of the items by the selection that a user can make in multiple dropdownlist. For example. If you have a dropdownlist with 10000 projectteams it could be possible to add a few selections before you select the project team like:

Select a Company

Select a Department

Select a Projectteam

This will filter the project team dropdownlist because you first selected a specific company and department so there are less projectteams left. I hope this helps

Regards,

Gunther,

Its not only the problem with the dropdown list, but also with gridview when i has more nubmer of rows.

when i removed the ajax controls, it worked fine.

sansav_p

Thank you for your answers.

The problem is that we are in a production environment, where I can't seperate the filter into several filters and I really need all the entries in the dropdownlist at the moment.

The thing I can't understand is why the page is fast without partial rendering and very very slow with partial rendering. I think I do nothing special and a solution for this should exist. Perhaps it can be solved with a dropdownlist from another vendor.

I will be happy with every solution or help I can get.