C#之文件下载

string path="/Dir/01.txt";  //文件相对路径
string Files = Server.MapPath(path);
                if (File.Exists(Files))
                {
                    try
                    {
                        System.IO.FileInfo DownloadFile = new System.IO.FileInfo(Files);
                        string fileName = DownloadFile.Name;
                        System.Web.HttpContext context = System.Web.HttpContext.Current;
                        Response.Clear();
                        Response.ClearHeaders();
                        Response.Buffer = false;
                        Response.ContentType = "application/octet-stream ";
                        Response.AddHeader("Content-Disposition", "attachment;filename=\"" + context.Server.UrlEncode(String.Format("{0}", fileName)) + "\"");
                        Response.AddHeader("Content-Length", DownloadFile.Length.ToString());
                        Response.AddHeader("Content-Transfer-Encoding", "binary");
                        Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
                        Response.WriteFile(Files);
                        Response.Flush();
                        Response.End();
                    }
                    catch
                    {
                        lblinfo.Text = "无法找到该文件！文件可能已经被移动或者删除。";
                    }
                }