<asp:scriptmanager id="ScriptManager1" runat="server" xmlns:asp="#unknown" />
<asp:updatepanel runat="server" id="UpdatePanel1" xmlns:asp="#unknown">
<contenttemplate>
<asp:dropdownlist runat="server" id="ddlCaseFilesNew" datasourceid="dsCaseFiles">
DataTextField="Display" DataValueField="FileID" OnPreRender="ddl_PreRender" Width="300px"
AutoPostBack="true" OnSelectedIndexChanged="ddlCaseFilesNew_SelectedIndexChanged" Visible="False">
<asp:listitem>Item 1</asp:listitem>
</asp:dropdownlist>
</contenttemplate>
<triggers>
<asp:asyncpostbacktrigger controlid="ddlCaseFilesNew" eventname="SelectedIndexChanged" />
</triggers>
</asp:updatepanel>
<script runat="server">
protected void ddlCaseFilesNew_SelectedIndexChanged(object sender, EventArgs e)
{
hidNewCaseFile.Value = ddlCaseFilesNew.SelectedItem.Value;
}
</script>