AjaxControlToolkit AutoCompleteExtender实例应用

<td class="style23">
 <asp:TextBox ID="tbNum" BackColor="#CCFFFF" runat="server" AutoCompleteType="Disabled"
 Width="289px"></asp:TextBox>
<asp:AutoCompleteExtender ID="tbNum_AutoCompleteExtender" runat="server" FirstRowSelected="true"
Enabled="True" ServicePath="Infor.asmx" ServiceMethod="GetTableInfor"
TargetControlID="tbNum" MinimumPrefixLength="1" EnableCaching="true" CompletionSetCount="10"
  CompletionInterval="100" UseContextKey="True">
 </asp:AutoCompleteExtender>
</td>

Infor.asmx文件

[WebMethod]
        public string[] GetTableInfor(string prefixText, int count)
        {
            string SQL_STR = "select top 10 ProNum from Tables where ProNum like '%" + prefixText + "%'"; 
            DataSet ds = SQLHelper.Query(SQL_STR);
            count = ds.Tables[0].Rows.Count;
            string[] array = new string[count];
            for (int i = 0; i < count; i++)
            {
                array[i] = ds.Tables[0].Rows[i]["NumName"].ToString();
            }
            return array;

        }