private void GrpStudisp_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex == 4)
            {
                DialogResult result = MessageBox.Show("Are you sure you want to delete this Group Student?", "Group Student", MessageBoxButtons.YesNo);
                if (result == DialogResult.Yes)
                {
                    try
                    {
                        con.Close();
                        con.Open();
                        int index = GrpStudisp.CurrentCell.RowIndex;
                        GrpStudisp.Rows[index].Selected = true;
                        string     id  = GrpStudisp.SelectedCells[1].Value.ToString();
                        SqlCommand cmd = new SqlCommand("DELETE FROM GroupStudent WHERE StudentId = '" + id + "';", con);
                        cmd.ExecuteNonQuery();
                        con.Close();
                        GrpStudisp.Rows.RemoveAt(index);
                        GrpStudisp.DataSource = dt1;
                        MessageBox.Show("Deleted!");
                    }
                    catch
                    {
                        con.Close();
                        MessageBox.Show("Something went wrong!");
                    }
                }
                else if (result == DialogResult.No)
                {
                    updatepan.Hide();
                    upgrpstu.Hide();

                    panel5.Hide();
                    panel1.Hide();
                    GroupStudentPan.Hide();
                    stugrpdispan.Show();
                }
            }
            if (e.ColumnIndex == 5)
            {
                DialogResult result = MessageBox.Show("Are you sure you want to Update this Group Student?", "GroupStudent", MessageBoxButtons.YesNo);
                if (result == DialogResult.Yes)
                {
                    panel5.Hide();
                    panel1.Hide();
                    GroupStudentPan.Hide();
                    stugrpdispan.Hide();
                    upgrpstu.Show();
                }
                else
                {
                    this.Hide();
                    Display obj = new Display();
                    obj.Show();
                }
            }
        }
 private void grpstu_Click(object sender, EventArgs e)
 {
     updatepan.Hide();
     upgrpstu.Hide();
     //AddStudent.Hide();
     panel5.Hide();
     panel1.Hide();
     GroupStudentPan.Hide();
     stugrpdispan.Show();
 }
        private void Form1_Load(object sender, EventArgs e)
        {
            disp_data(); //display data of Student
            upgrpstu.Hide();

            disp_data_grpstu();//display data of student group
            //panel2.Hide();

            GroupStudentPan.Hide();


            updatepan.Hide();
            panel5.Hide();
            stugrpdispan.Hide();
            panel1.Show();
        }