AutoCompelete Control Extender with With DB

using System;
using System.Web;
using System.Collections;
using System.Collections.Generic;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Data;
using System.Data.SqlClient;
using System.Configuration; 

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.Web.Script.Services.ScriptService]
public class AutoComplete : WebService
{
    string connectionString = string.Empty;
    DataTable dt = null;
    SqlCommand objCommnad = null;
    SqlDataAdapter da = null;
    SqlConnection con = null;
    public AutoComplete()
    {
    }

    [WebMethod]
    public string[] GetCompletionList(string prefixText, int count)
    {
        if (count == 0)
        {
            count = 10;
        }

        if (prefixText.Equals("xyz"))
        {
            return new string[0];
        }

        Random random = new Random();
        List<string> items = new List<string>(count);
        for (int i = 0; i < count; i++)
        {
            char c1 = (char)random.Next(65, 90);
            char c2 = (char)random.Next(97, 122);
            char c3 = (char)random.Next(97, 122);

            items.Add(prefixText + c1 + c2 + c3);
        }

        //return items.ToArray();

        return getCompany(prefixText); 

        /////////////////Rizwan Code Here \\\\\\\\\\\\\\\\\\\\\\\

    }
    private string[] getCompany(string CompanyNameLike)
    {
        connectionString = ConfigurationManager.AppSettings["ConStr1"].ToString();
        con = new SqlConnection(connectionString);
        try
        {
            con.Open();
            objCommnad = new SqlCommand();
            objCommnad.Connection = con;
            objCommnad.CommandType = CommandType.StoredProcedure;
            objCommnad.CommandText = "LU_Select_ProPerty";
            objCommnad.Parameters.Add("@CompanyName", SqlDbType.VarChar).Value = CompanyNameLike;
            da = new SqlDataAdapter(objCommnad);
            dt = new DataTable();
            da.Fill(dt);
            //return dt;
        }
        catch (Exception ex)
        {
            con.Close();
            throw ex;
        }
        finally
        {
            con.Close();
        }
        List<string> items = new List<string>(dt.Rows.Count);
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            items.Add(dt.Rows[i]["pro_name"].ToString());     
        }
        return items.ToArray() ;
    }
}