private void Exit_Click(object sender, EventArgs e)
{
1. if (ds.HasChanges())
   {
2.   DialogResult b1;
3.   b1 = MessageBox.Show("Dataset has changed, Saved ", "", System.Windows.Forms.MessageBoxButtons.YesNo);
4.  if (b1 == DialogResult.Yes)
5.     cb = new SqlCommandBuilder(da);
6.  da.Update(ds, "stTable");
7.  con.Close();
8.  Close();
    }
9.  else
10.  Close();
}
