private async void XepTietHocForm_Load(object sender, EventArgs e)
        {
            toolTip.ShowAlways = true;

            dateNgay.EditValue    = Ngay;
            cbxTietHoc.DataSource = tietHocSuggestions;
            dateNgay.SetSelection(DateTime.Now);
            typingTiet.ngay = Ngay;

            dateNgay.MinValue  = HocKy.ngayBatDau;
            dateNgay.MaxValue  = HocKy.ngayKetThuc;
            this.ActiveControl = txtLop;

            hinhThucList = await apis.GetHinhThucs();

            List <string> hts = new List <string>();

            foreach (HinhThuc ht in hinhThucList)
            {
                hts.Add(ht.ten);
            }
            ;
            cbxHinhThuc.DataSource = hts;

            //Thêm gợi ý môn học
            monHocList = await apis.GetMonHocs();

            AutoCompleteStringCollection collection = new AutoCompleteStringCollection();

            monHocList.ForEach(mon => { collection.Add(mon.ToString()); });
            txtMonHoc.MaskBox.AutoCompleteSource       = AutoCompleteSource.CustomSource;
            txtMonHoc.MaskBox.AutoCompleteMode         = AutoCompleteMode.SuggestAppend;
            txtMonHoc.MaskBox.AutoCompleteCustomSource = collection;

            txtLop.Focus();
            refreshTypingTiet();
        }