AUTO COMPLETE EXTENDER IN ASP.NET

 <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
       
<asp:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server"
       
 TargetControlID="TextBox1" ServiceMethod="GetCompletionList"
            ServicePath="AjaxLearning.asmx" MinimumPrefixLength="1"
            CompletionListHighlightedItemCssClass="autocomplete_highlightedListItem"
            CompletionListItemCssClass="autocomplete_listItem"
            CompletionListCssClass="autocomplete_completionListElement"
            ShowOnlyCurrentWordInCompletionListItem="True">
</asp:AutoCompleteExtender>