Devx PivotGrid Export

ool saveAs = true;
            DevExpress.Utils.Paint.XPaint.ForceGDIPlusPaint();
            using (MemoryStream stream = new MemoryStream())
            {
                ASPxPivotGridExporter1.OptionsPrint.PrintHeadersOnEveryPage = true;
                ASPxPivotGridExporter1.OptionsPrint.PrintFilterHeaders = DevExpress.Utils.DefaultBoolean.True;
                ASPxPivotGridExporter1.OptionsPrint.PrintColumnHeaders = DevExpress.Utils.DefaultBoolean.True;
                ASPxPivotGridExporter1.OptionsPrint.PrintRowHeaders = DevExpress.Utils.DefaultBoolean.True;
                ASPxPivotGridExporter1.OptionsPrint.PrintDataHeaders = DevExpress.Utils.DefaultBoolean.True;

                string contentType = "", fileName = "";

               
                fileName = "PivotGrid.xls";

                ASPxPivotGridExporter1.ExportToXls(stream); // ---->> Exeption raises

                byte[] buffer = stream.GetBuffer();

                string disposition = saveAs ? "attachment" : "inline";
                Response.Clear();
                Response.Buffer = false;
                Response.AppendHeader("Content-Type", contentType);
                Response.AppendHeader("Content-Transfer-Encoding", "binary");
                Response.AppendHeader("Content-Disposition", disposition + "; filename=" + fileName);
                Response.BinaryWrite(buffer);
                Response.End();
            }

Çözümü Yukarıdaki gibidir.