C#通过文件流下载文件

1、该方法传入的参数为需要下载的文件(需要包含绝对路径)

/// <summary>
        /// 通过文件流下载文件
        /// </summary>
        /// <param name="url">文件名称(包含目录和后缀名)</param>
        private void DownLoadPic(string url)
        {
            string sFileName = url ;
            FileStream fileStream = new FileStream(sFileName, FileMode.Open);
            long fileSize = fileStream.Length;
            byte[] fileBuffer = new byte[fileSize];
            fileStream.Read(fileBuffer, 0, (int)fileSize);
            //如果不写fileStream.Close()语句，用户在下载过程中选择取消，将不能再次下载
            fileStream.Close();

            Context.Response.ContentType = "application/octet-stream";
            Context.Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(这里是你想要下载文件的文件名), Encoding.UTF8));
            Context.Response.AddHeader("Content-Length", fileSize.ToString());

            Context.Response.BinaryWrite(fileBuffer);
            Context.Response.End();
            Context.Response.Close();
        }

2、下载指定路径的文件

/// <summary>
        /// 文?件t流ⅰ?方?式?下?载?附?件t
        /// </summary>
        /// <param name="path">包含文件名的相对路径</param>
        /// <param name="name">下载后的新文件名</param>
        public static void DownloadFile(string path, string name)
        {
            if (!string.IsNullOrEmpty(path))
            {
                string filePath = HttpContext.Current.Server.MapPath(path);
                FileInfo fileInfo = new FileInfo(filePath);
                HttpContext.Current.Response.Clear();
                HttpContext.Current.Response.ClearContent();
                HttpContext.Current.Response.ClearHeaders();
                HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(Encoding.GetEncoding(65001).GetBytes(name)));
                HttpContext.Current.Response.AddHeader("Content-Length", fileInfo.Length.ToString());
                HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");
                HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
                HttpContext.Current.Response.ContentType = "application/octet-stream";
                HttpContext.Current.Response.WriteFile(fileInfo.FullName);
                HttpContext.Current.Response.Flush();
                HttpContext.Current.Response.End();
            }
        }