Autocomplete method not called using AutoExtender - asp.net

Question

I have Ajax AutoExtender control asociated with textbox. Suggested data are selected from database. But my AutoComplete code is not even fired. What can be wrong with the code? Thanks.
<asp:TextBox ID="txtSports" runat="server" CssClass="textbox" placeholder="Sport"></asp:TextBox>
<ajaxToolkit:AutoCompleteExtender ID="AutoCompleteExtender1" MinimumPrefixLength="1" ServicePath="~/AutoComplete.asmx" CompletionSetCount="20" CompletionInterval="0000" EnableCaching="true" UseContextKey="True" ServiceMethod="GetCompletionList" TargetControlID="txtSports" runat="server"></ajaxToolkit:AutoCompleteExtender>
AutoComplete.asmx file:
Imports System.Web.Services.Protocols
Imports System.ComponentModel
Imports System.Data.SqlClient
Imports AjaxControlToolkit
' To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
<System.Web.Script.Services.ScriptService()> _
<System.Web.Services.WebService(Namespace:="http://tempuri.org/")> _
<System.Web.Services.WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ToolboxItem(False)> _
Public Class AutoComplete
Inherits System.Web.Services.WebService
<System.Web.Services.WebMethodAttribute, System.Web.Script.Services.ScriptMethodAttribute> _
Public Shared Function GetCompletionList(prefixText As String, count As Integer, contextKey As String) As String()
Dim listString As New List(Of String)()
Dim connStr As String = System.Configuration.ConfigurationManager.ConnectionStrings("SportovniPlanetaCS").ConnectionString.ToString()
Using conn As New SqlConnection(connStr)
Dim cmd As New SqlCommand((Convert.ToString("SELECT Sport, SportId FROM Sports WHERE Sport LIKE #Sport")))
cmd.Parameters.AddWithValue("#Sport", prefixText)
conn.Open()
Dim dr As SqlDataReader = cmd.ExecuteReader()
If dr.HasRows Then
While dr.Read()
listString.Add(AutoCompleteExtender.CreateAutoCompleteItem(dr("Sport").ToString(), dr("SportId").ToString()))
End While
End If
End Using
Dim str As String() = listString.ToArray()
Return str
End Function
End Class

Answer 1

Well i Don't think you need to use a separate WebService for it. you could create a web method and make it work.
You could see example here...
AutoComplete Demonstration

Answer 2

In AjaxToolKit add
OnClientItemSelected="ClientItemSelected"
add javascript
function ClientItemSelected(source, e)
{
source.get_element().value = (document.all) ? e._item.innerText : e._item.textContent;
var str = $('#<%=txtsports.ClientID %>').val();
}