public HoaDon() { InitializeComponent(); this.hdbll = new HoaDonBLL(); string s = hdbll.ThoiGian(); DateTime dt = Convert.ToDateTime(s); thang1 = Convert.ToInt32(dt.Month.ToString()) + 1; thang.Text = thang1.ToString() + "/" + dt.Year.ToString(); dgvTenDV.DataSource = hdbll.DV(); butSua.Enabled = false; butThem.Enabled = false; butXoaDV.Enabled = false; butLapHD.Enabled = false; butXoaHD.Enabled = false; button1.Enabled = false; }