Auto Complete Text Box

Html:

<tr>

            <td>

                City

            </td>

            <td>

                :

            </td>

            <td>

                <asp:TextBox ID="txtCitySearch" runat="server" AutoCompleteType="DisplayName" OnTextChanged="txtCitySearch_TextChanged"

                    AutoPostBack="true"></asp:TextBox>

                <asp:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server" ServiceMethod="GetCities"

                    MinimumPrefixLength="2" CompletionInterval="100" CompletionSetCount="10" EnableCaching="false"

                    TargetControlID="txtCitySearch" FirstRowSelected="false" UseContextKey="True"

                    CompletionListElementID="autocompleteDropDownPanel">

                </asp:AutoCompleteExtender>

            </td>

        </tr>

C#

[System.Web.Services.WebMethodAttribute(), System.Web.Script.Services.ScriptMethodAttribute()]

    public static string[] GetCities(string prefixText, int count)

    {

        var citySearchKey = from city in new CityManager().GetAllCities().GroupBy(city => city.Name).Select(city => city.First()).ToList()

                            where city.Name.ToLower().StartsWith(prefixText.ToLower().Trim())

                                   || city.Name.ToLower().Contains(prefixText.ToString().ToLower().Trim())

                            select city.Name;

        return citySearchKey.ToArray();

    }