private void delstu_Click(object sender, EventArgs e) { if (dataGridstudent.SelectedCells.Count != 0) { int rw = dataGridstudent.SelectedCells[0].RowIndex; string cmd = string.Format("DELETE FROM Student where Id = '{0}'", dataGridstudent.Rows[rw].Cells["Id"].Value.ToString()); SqlCommand del = new SqlCommand(cmd, DatabaseConnection.getInstance().getConnection()); int count = del.ExecuteNonQuery(); students s = new students(); this.Hide(); s.Show(); } }