รบกวนสอบถาม print preview รายงานจาก crystal report ครับ

protected void Page_Load(object sender, EventArgs e)
        {
            int IDd = (int)Session["ID"];
            DataTable dtTable = Session["download"] as DataTable;
            if (IDd != 0)
            {
                string test = dtTable.Rows[IDd - 1]["Name"].ToString();
                if (dtTable.Rows[IDd - 1]["DownloadFile"] != DBNull.Value)
                {
                    byte[] file = (byte[])dtTable.Rows[IDd - 1]["DownloadFile"];

                    Response.Clear();
                    Response.Buffer = true;
                    Response.Charset = "";
                    Response.Cache.SetCacheability(HttpCacheability.NoCache);
                    Response.ContentType = "application / pdf";
                    Response.AppendHeader("Content-Disposition", "attachment; filename=" + test + ".pdf");
                    Response.BinaryWrite(file);
                    Response.Flush();
                    Response.End();
                }
                else
                {
                    ScriptManager.RegisterStartupScript(this, this.GetType(), "Redit", "alert('ไม่มีเอกสารนี้'); window.location='" + Request.ApplicationPath + "applicationform.aspx';", true);

                }
            }