private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            string ColName = dataGridView1.Columns[e.ColumnIndex].Name;

            if (ColName == "colEdit")
            {
                Add_std_group frm = new Add_std_group();
                frm.textBox1.Text       = _yr;
                frm.comboBox1.Text      = _pro;
                frm.numericUpDown1.Text = _gno;
                frm.numericUpDown2.Text = _subno;
                frm.ShowDialog();
            }
            else if (ColName == "colDelete")
            {
                if (MessageBox.Show("Are you sure you want to delete this record ?", "Delete Record", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
                {
                    ;
                }
                {
                    cn.Open();
                    cm = new MySqlCommand("delete from stdgroup_table where year like'" + _yr + "'", cn);
                    cm.ExecuteNonQuery();
                    cn.Close();
                    MessageBox.Show("Record has been Successfully deleted !", "Deleted Record", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    LoadRecords();
                }
            }
        }
        private void button2_Click(object sender, EventArgs e)
        {
            Add_std_group f2 = new Add_std_group();

            this.Hide();
            f2.Show();
        }