ASP.NET Ajax AutoComplete Textbox

USE [master]
GO

CREATE DATABASE [AutoCompleteSampleDB] 
GO

USE [AutoCompleteSampleDB]
GO

CREATE TABLE [dbo].[Cities](
	[CityId] [int] IDENTITY(1,1),
	[Description] [nvarchar](100),
	[StateId] [int] NULL,
	[TimeZone] [tinyint] NULL,
	[Active] [bit] NULL
)

GO


INSERT INTO [Cities] ([Description]) VALUES (N'Wesco')
INSERT INTO [Cities] ([Description]) VALUES (N'Wescosville')
INSERT INTO [Cities] ([Description]) VALUES (N'Weser')
INSERT INTO [Cities] ([Description]) VALUES (N'Weskan')

Imports System.Web
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.Linq
Imports System.Data
Imports System.Data.SqlClient


<System.Web.Script.Services.ScriptService()> _
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Public Class AutoCompleteWebServices
    Inherits System.Web.Services.WebService

    <WebMethod()> _
    Public Function GetDistrictList(ByVal prefixText As String, ByVal count As Integer, ByVal contextKey As String) As String()

        Dim returnList As New List(Of String)

        Try

            Dim _sId As String = String.Empty
            Dim CallId As String = String.Empty
            Dim CallerPhoneCode As String = String.Empty

            Dim params As String() = contextKey.Split("|")
            _sId = params(0)
            CallId = params(1)
            CallerPhoneCode = params(2)


            Dim objConn As New SqlConnection
            Dim dtAdapter As SqlDataAdapter
            Dim dt As New DataTable
            Dim i As Integer = 0


            Dim strConnString As String
            strConnString = ConfigurationManager.ConnectionStrings( "SQL2008SamplesDBConnectionString").ConnectionString
            objConn = New SqlConnection(strConnString)
            objConn.Open()

            Dim strSQL As String
            strSQL = "SELECT * FROM Cities WHERE Description like '" & prefixText & "%'"

            dtAdapter = New SqlDataAdapter(strSQL, objConn)
            dtAdapter.Fill(dt)

            dtAdapter = Nothing

            objConn.Close()
            objConn = Nothing

            For i = 0 To dt.Rows.Count - 1
                returnList.Add(dt.Rows(i)("Description").ToString())
            Next

            dt.Clear()

        Catch ex As Exception

        End Try

        Return returnList.ToArray()

    End Function

End Class