private void btnLapBaoCao_Click(object sender, EventArgs e)
        {
            if (String.IsNullOrEmpty(cbbNam.Text) && String.IsNullOrEmpty(cbbThang.Text))
            {
                return;
            }

            DataTable dt = BUS_LapBaoCaoThang.GetBaoCaoThang(cbbThang.Text, cbbNam.Text);

            dgvBaoCaoChiTiet.DataSource = dt;
            int tongDT = 0;

            foreach (DataRow dr in dt.Rows)
            {
                tongDT += int.Parse(dr["DoanhThu"].ToString());
            }
            lblTongDoanhThu.Text = tongDT.ToString();
        }
        private void frmLapBaoCaoThang_Load(object sender, EventArgs e)
        {
            BUS_LapBaoCaoThang.LoadLapBaoCaoThang();

            mListMonths = BUS_LapBaoCaoThang.GetListOfListMonths();
            if (mListMonths.Count != 0)
            {
                cbbNam.DataSource   = BUS_LapBaoCaoThang.GetListYears();
                cbbThang.DataSource = mListMonths[0];

                if (cbbThang.Items.Count > 0)
                {
                    cbbThang.SelectedIndex = 0;
                }
                if (cbbNam.Items.Count > 0)
                {
                    cbbNam.SelectedIndex = 0;
                }
            }
        }