private void cboTheLoai_LoadDataBase()
        {
            DataTable dt = BUS_OBJ.loadDSTheLoai();

            cboTheLoai.DataSource    = dt;
            cboTheLoai.DisplayMember = "TenTheLoai";
            cboTheLoai.ValueMember   = "MaTheLoai";
        }
        private void HienThiDuLieu()
        {
            this.dgvTheLoai.DataSource = null;
            this.dgvTheLoai.DataSource = BUS_OBJ.loadDSTheLoai();

            dgvTheLoai.DefaultCellStyle.Alignment            = DataGridViewContentAlignment.MiddleLeft;
            dgvTheLoai.Columns[0].HeaderText                 = "Mã thể loại";
            dgvTheLoai.Columns[0].DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;

            dgvTheLoai.Columns[1].HeaderText = "Tên thể loại";

            foreach (DataGridViewColumn col in dgvTheLoai.Columns)
            {
                col.HeaderCell.Style.Alignment = DataGridViewContentAlignment.MiddleCenter;
                col.HeaderCell.Style.Font      = new Font("Segoe UI", 12F, FontStyle.Bold, GraphicsUnit.Pixel);
            }
        }