How to implement autoextender for google suggest like functionality

I have seen that lot of my friends having problem in implementing the autoextender.

so that i have tried to describe that how to implement it.it may make easier to implement autoextender.

Step1:Add required controls

• Add a text box from your toolbox.

• Add a autoextender and set the TargetControlID of it by setting the id of above textbox.for eg.

<asp:TextBox ID="txtname" runat="server"/>
<ajaxToolkit:AutoCompleteExtender ID="aceName" Enabled="true" runat="server" MinimumPrefixLength="1"
TargetControlID="txtname"  CompletionSetCount="20" CompletionInterval="0000" EnableCaching="true"
 ServiceMethod="GetName"  ServicePath="AutoExtender.asmx"/>

Note: please make sure you have given the virtual path of web service and name of web method correctly.

Step2:Create the web service

 public class AutoExtender : System.Web.Services.WebService
 {

 [WebMethod]
 public string[] GetName(string prefixText)
 { 
    List<string> listString = new List<string>();
    using (SqlConnection con = new SqlConnection("Initial Catalog=Dbname;Server=.;User ID=sa;Password=pwd"))
    {
     SqlCommand cm = new SqlCommand("SELECT Name,ID FROM tblUser Where  Name like '" + prefixText + "%'", con);
     con.Open();
     SqlDataReader dr = cm.ExecuteReader();
      if (dr.HasRows)
      {
       while (dr.Read())
       {
        listString.Add(AutoCompleteExtender.CreateAutoCompleteItem(dr["Name"].ToString(), dr["ID"].ToString()));
         //c.FullName, serializer.Serialize(c))
         }
         }
       }
            string[] str = listString.ToArray();
            return str;

  }
}

Hope this will help..