public void ExportReport(XtraReport report, string fileName, string fileType, bool inline)
    {
        MemoryStream stream = new MemoryStream();

        Response.Clear();

        if (fileType == "xls")
        {
            report.ExportToXls(stream);
        }
        if (fileType == "pdf")
        {
            report.ExportToPdf(stream);
        }
        if (fileType == "rtf")
        {
            report.ExportToRtf(stream);
        }
        if (fileType == "csv")
        {
            report.ExportToCsv(stream);
        }

        Response.ContentType = "application/" + fileType;
        Response.AddHeader("Accept-Header", stream.Length.ToString());
        Response.AddHeader("Content-Disposition", (inline ? "Inline" : "Attachment") + "; filename=" + fileName + "." + fileType);
        Response.AddHeader("Content-Length", stream.Length.ToString());
        //Response.ContentEncoding = System.Text.Encoding.Default;
        Response.BinaryWrite(stream.ToArray());
        Response.End();
    }
        private void exportFileCsv(XtraReport report)
        {
            string         reportPath = "";
            SaveFileDialog sf         = new SaveFileDialog();

            sf.FileName = "Save Here.csv";
            if (sf.ShowDialog() == DialogResult.OK)
            {
                reportPath = Path.GetDirectoryName(sf.FileName) + sf.FileName;
                try
                {
                    report.ExportToCsv(sf.FileName);
                    MessageBox.Show("Lưu thành công!");
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        }