private void btnXuatBaoCao_Click(object sender, EventArgs e)
        {
            List <DoanhThu>      listReport = new List <DoanhThu>();
            List <ProductDetail> list       = context.ProductDetails.Where(x => x.Order.OrderDate > dtpFrom.Value && x.Order.OrderDate < dtpTo.Value).ToList();

            if (list.Count > 0)
            {
                foreach (ProductDetail i in list)
                {
                    DoanhThu r = new DoanhThu();
                    r.Id        = i.Id;
                    r.OrderId   = i.OrderId.Value;
                    r.ProductId = i.ProductId.Value;
                    r.Quantity  = i.Quantity.Value;
                    r.UnitPrice = i.UnitPrice.Value;
                    listReport.Add(r);
                }
                this.reportViewer1.LocalReport.ReportPath = "ReportDoanhTHu.rdlc";
                var resource = new ReportDataSource("DoanhThuDataSet", listReport);
                this.reportViewer1.LocalReport.DataSources.Clear();
                this.reportViewer1.LocalReport.DataSources.Add(resource);
                this.reportViewer1.RefreshReport();
            }
            else
            {
                BaoCaoDoanhThu();
            }
            this.reportViewer1.RefreshReport();
        }
        public void BaoCaoDoanhThu()
        {
            List <DoanhThu>      listReport = new List <DoanhThu>();
            List <ProductDetail> list       = context.ProductDetails.ToList();

            foreach (ProductDetail i in list)
            {
                DoanhThu r = new DoanhThu();
                r.Id        = i.Id;
                r.OrderId   = i.OrderId.Value;
                r.ProductId = i.ProductId.Value;
                r.Quantity  = i.Quantity.Value;
                r.UnitPrice = i.UnitPrice.Value;
                listReport.Add(r);
            }
            this.reportViewer1.LocalReport.ReportPath = "ReportDoanhTHu.rdlc";
            var resource = new ReportDataSource("DoanhThuDataSet", listReport);

            this.reportViewer1.LocalReport.DataSources.Clear();
            this.reportViewer1.LocalReport.DataSources.Add(resource);
            this.reportViewer1.RefreshReport();
            this.reportViewer1.RefreshReport();
        }