<asp:DropDownList ID="txtCity" runat="server" CssClass="input_bar"
onselectedindexchanged="txtCity_SelectedIndexChanged" TabIndex="0">
</asp:DropDownList>
<ajaxToolkit:CascadingDropDown ID="AutoCompleteCity" runat="server" Category="Country"
TargetControlID="txtCity" PromptText="Hyderabad" ServicePath="WebService.asmx"
ServiceMethod="GetCityList">
</ajaxToolkit:CascadingDropDown>
protected void txtCity_SelectedIndexChanged(object sender, EventArgs e)
{
Session["City"] = Server.HtmlEncode(txtCity.SelectedItem.Text);
lblTitle.Text = txtCity.SelectedItem.Text;
}
but the event is not raised y? please help me