private void btnAddStudent_Click(object sender, EventArgs e)
        {
            frmAdd_Edit  frmadd = new frmAdd_Edit();
            DialogResult rs     = frmadd.ShowDialog();

            if (frmadd.student.MSSV == null)
            {
                return;
            }

            // Mỗi lần Add là mỗi lần load cả List , có nên không nhỉ ???
            ListViewItem St = new ListViewItem(STT.ToString());

            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.MSSV.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.name.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.gender.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.birthday.ToShortDateString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.address.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.numberPhone.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.faculty.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.major.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.Class.ToString()));
            St.SubItems.Add(new ListViewItem.ListViewSubItem(St, frmadd.student.course.ToString()));

            this.lstStudent.Items.Add(St);
            StudentController.AddStudent(frmadd.student);
            STT++;
        }
        private void btnEditStudent_Click(object sender, EventArgs e)
        {
            // Dùng để kiểm tra edit có bị trung MSSV không

            if (this.lstStudent.SelectedItems.Count <= 0)        //???
            {
                MessageBox.Show("Bạn chưa chọn đối tượng?", "Thông báo",
                                MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            if (this.lstStudent.Items.Count == 0)
            {
                return;
            }

            // Tìm ST với MSSV tương ứng trong database
            Student ST = new Student();

            ST = StudentController.GetStudentbyID(this.lstStudent.SelectedItems[0].SubItems[1].Text);

            if (ST.MSSV == null)
            {
                return;
            }
            string       oldMSSV = this.lstStudent.SelectedItems[0].SubItems[1].Text;
            frmAdd_Edit  frmedit = new frmAdd_Edit(ref ST);
            DialogResult rs      = frmedit.ShowDialog();

            if (frmedit.edit == true)
            {
                // Tìm STT cho ST
                for (int i = 0; i < this.lstStudent.Items.Count; i++)
                {
                    if (lstStudent.Items[i].SubItems[1].Text == ST.MSSV)
                    {
                        STT = i + 1;
                        break;
                    }
                }

                ListViewItem St = new ListViewItem(STT.ToString());
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.MSSV.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.name.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.gender.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.birthday.ToShortDateString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.address.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.numberPhone.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.faculty.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.major.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.Class.ToString()));
                St.SubItems.Add(new ListViewItem.ListViewSubItem(St, ST.course.ToString()));

                //Update
                StudentController.UpdateStudent(ST, oldMSSV);
                this.lstStudent.Items[this.lstStudent.SelectedItems[0].Index] = St;
            }
        }