public void btnTemplate_Click(object sender, EventArgs e)
        {

            string strResult = string.Empty;
            string strPath = Server.MapPath("~/uploadfile/");
            string strFile = string.Format(@"{0}\{1}", strPath, "base.xls");

            using (FileStream fs = new FileStream(strFile, FileMode.Open))
            {
                byte[] bytes = new byte[(int)fs.Length];
fs.Read(bytes, 0, bytes.Length);
                fs.Close();
                Response.ContentType = "application/octet-stream";
                Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode("base.xlsx", System.Text.Encoding.UTF8));
                Response.BinaryWrite(bytes);
                Response.Flush();
                Response.End();
            }
        }
strPath:模板存放路径