Implement autocomplete in textbox based on Name column

http://www.dotnetspider.com/resources/30998-Creating-winforms-AutoComplete-TextBox-using-C.aspx
http://www.dotnetspider.com/forum/310781-binding-id-text-autocomplete-textbox-from.aspx
http://www.dotnetspider.com/resources/45209-Ajax-Auto-Complete-Without-WebServices-aspnet.aspx
http://www.dotnetspider.com/forum/331591-Why-Textbox-autocomplete-not-working-first-character.aspx

<ajaxToolkit:AutoCompleteExtender ID="autoExtender" runat="server" TargetControlID="txt1" ServiceMethod="GetEmpNames" 
MinimumPrefixLength="1" CompletionInterval="100" EnableCaching="false" CompletionSetCount="10"></ajaxToolkit:AutoCompleteExtender>

[System.Web.Script.Services.ScriptMethod()]
    [System.Web.Services.WebMethod]
    public static List GetEmpNames(string prefixText)
    {
        SqlConnection con = new SqlConnection("DataBase=ENGSOFT;User id=sa;Password=P@ssword9");
        con.Open();
        SqlCommand cmd = new SqlCommand("select empno, ename,job,mgr,hiredate,sal,comm,picture from emp where 
ename like '%'+ @Name+'%'", con);
        cmd.Parameters.AddWithValue("@Name", prefixText);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);

        List Empname = new List();

        for (int i = 0; i < dt.Rows.Count; i++)
        {
            Empname.Add(dt.Rows[i]["ename"].ToString());
        }
        con.Close();
        return Empname;
    }

http://www.dotnetspider.com/resources/45209-Ajax-Auto-Complete-Without-WebServices-aspnet.aspx

 AutoCompleteStringCollection collection = new AutoCompleteStringCollection();
string connectionString="your connection string";
SqlConnection con = new SqlConnection(connectionString);
con.Open();
SqlDataAdapter ad = new SqlDataAdapter("select sname from tbl_Student", con);
DataTable dt = new DataTable();
ad.Fill(dt);
if(dt.Rows.Count>0)
{
for (int i = 0; i < dt.Rows.Count; i++)
{
  collection.Add(dt.Rows[i].ItemArray[0].ToString());
}
}

textBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
textBox1.AutoCompleteCustomSource = collection;