ActiveReports之导出excel

            DbContextBase db = new DbContextBase();
            var list = db.PurchaseOrderTBs.ToList();
            List<PurchaseOrderView> list2 = new List<PurchaseOrderView>();
            foreach (var item in list)
            {
                list2.Add(new PurchaseOrderView()
                {
                    OrderNo = item.OrderNo,
                    PickNum = item.PickNum,
                    ProductPrice = item.ProductPrice,
                    ProductAmount = item.ProductPrice * item.PickNum
                });
            }
            ReportDataSource ReportDataSource = new ReportDataSource();
            ReportDataSource.Name = "DataSet1";
            ReportDataSource.Value = list2;

            ReportViewer rvDoc = new ReportViewer();
            rvDoc.LocalReport.ReportPath = Server.MapPath("~/Reports/Report2.rdlc");
            rvDoc.LocalReport.DataSources.Add(ReportDataSource);
            #region 导入excel
            Warning[] warnings;
            string[] streamids;
            string mimeType;
            string encoding;
            string extension;

            byte[] bytes = rvDoc.LocalReport.Render(
               "Excel", null, out mimeType, out encoding,
                out extension,
               out streamids, out warnings);

            FileStream fs = new FileStream(@"c:\output.xls",
               FileMode.Create);
            fs.Write(bytes, 0, bytes.Length);
            fs.Close();
            #endregion