inheritance class ConnectDatabase ไปใช้ใน class from : Form

using System.Data;
using System.Data.SqlClient;


namespace ConnectLibrary
{
    public class ConnectDatabase
    {
       SqlConnection cs = new SqlConnection("Data Source = big-PC; Initial Catalog = T_Database; Integrated Security = TRUE");
            SqlDataAdapter da = new SqlDataAdapter();

           da.SelectCommand = new SqlCommand("SELECT * FROM T_id", cs);
            ds.Clear();
            da.Fill(ds);
            dg.DataSource = ds.Tables[0];

            tblNamesBS.DataSource = ds.Tables[0];

            txtFirstName.DataBindings.Add(new Binding("Text", tblNamesBS, "FIRSTNAME"));
            txtLastName.DataBindings.Add(new Binding("Text", tblNamesBS, "LASTNAME"));
    }
}

using System.Data.SqlClient;
using ConnectLibrary;

namespace WindowsFormsApplication1
{
    public partial class from : Form
    { 
        public from()
        {
            InitializeComponent();
        }


       private void btnAdd_Click(object sender, EventArgs e)
        {                
            // อยากให้  inheritance  class  ConnectDatabase กดปุ่มนี้แล้วไป โชว์ 
            
        }