private void Delete_Click(object sender, EventArgs e)
{
1.  string sn;
2.  SqlCommand cmd = new SqlCommand();
3.  string sqlDel;
4.  con.Open();
5.  sn = textBox2.Text;
6.  sqlDel = "DELETE FROM stTable WHERE stno = " + sn;
7.  cmd.CommandText = sqlDel;
8.  cmd.Connection = con;
9.  cmd.ExecuteNonQuery();
10. ds.Clear();
11. da.Fill(ds, "stTable");
12. con.Close();
}
