AutoComplete Property in C# Windows Application

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Data.SqlClient;

                  

namespace WindowsFormsApplication1

{

    public partial class Form1 : Form

    {

        SqlConnection sqlcon = new SqlConnection(@"//Connection String//");

        SqlCommand sqlcom = new SqlCommand();

        SqlDataAdapter sqlada = new SqlDataAdapter();

        DataSet dset = new DataSet();

        AutoCompleteStringCollection namesCollection = new AutoCompleteStringCollection();                    

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            if (sqlcon.State == ConnectionState.Open)

                sqlcon.Close();

                sqlcon.Open();

                sqlcom.Connection = sqlcon;

                sqlcom.CommandText = "select * from TableName where Columnname like'" + txtNames.Text + "%'";

                sqlcom.ExecuteNonQuery();

                sqlada.SelectCommand = sqlcom;

                sqlada.Fill(dset, " TableName ");

                for (int i = 0; i < dset.Tables["TableName "].Rows.Count; i++)

            {

                namesCollection.Add(dset.Tables["Autocomplete"].Rows[i]["Names"].ToString());

            }

            txtNames.AutoCompleteMode = AutoCompleteMode. SuggestAppend;

            txtNames.AutoCompleteSource = AutoCompleteSource.CustomSource;

            txtNames.AutoCompleteCustomSource = namesCollection;

        }

    }

}