MVC 下载文件

 ???????//（1）返回filestream ?　其中：“text/plain”是文件MIME类型 ???????public FileStreamResult download() ???????{ ???????????string fileName = "aaa.txt";//客户端保存的文件名 ???????????string filePath = Server.MapPath("~/Document/123.txt");//路径 ???????????return File(new System.IO.FileStream(filePath, System.IO.FileMode.Open), "text/plain", fileName); ???????} ???????//（2）返回file ???????public FileResult downloadA() ???????{ ???????????string filePath = Server.MapPath("~/Document/123.txt");//路径 ???????????return File(filePath, "text/plain", "welcome.txt"); //welcome.txt是客户端保存的名字 ???????} ???????public ActionResult FileStreamDownload1() ???????{ ???????????var stream = new System.Net.WebClient().OpenRead("http://files.cnblogs.com/ldp615/Mvc_TextBoxFor.rar"); ???????????return File(stream, "application/x-zip-compressed", "test.rar"); ???????}

//（3）TransmitFile方法 ???????public void downloadB() ???????{ ???????????string fileName = "aaa.txt";//客户端保存的文件名 ???????????string filePath = Server.MapPath("~/Document/123.txt");//路径 ???????????System.IO.FileInfo fileinfo = new System.IO.FileInfo(filePath); ???????????Response.Clear(); ????????//清除缓冲区流中的所有内容输出 ???????????Response.ClearContent(); ?//清除缓冲区流中的所有内容输出 ???????????Response.ClearHeaders(); ?//清除缓冲区流中的所有头 ???????????Response.Buffer = true; ??//该值指示是否缓冲输出，并在完成处理整个响应之后将其发送 ???????????Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName); ???????????Response.AddHeader("Content-Length", fileinfo.Length.ToString()); ???????????Response.AddHeader("Content-Transfer-Encoding", "binary"); ???????????Response.ContentType = "application/unknow"; ?//获取或设置输出流的 HTTP MIME 类型 ???????????Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312"); //获取或设置输出流的 HTTP 字符集 ???????????Response.TransmitFile(filePath); ???????????Response.End(); ???????} ???????//（4）Response分块下载 ???????public void downloadC() ???????{ ???????????string fileName = "aaa.txt";//客户端保存的文件名 ???????????string filePath = Server.MapPath("~/Document/123.txt");//路径 ???????????System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath); ???????????if (fileInfo.Exists == true) ???????????{ ???????????????const long ChunkSize = 102400;//100K 每次读取文件，只读取100K，这样可以缓解服务器的压力 ???????????????byte[] buffer = new byte[ChunkSize]; ???????????????Response.Clear(); ???????????????System.IO.FileStream iStream = System.IO.File.OpenRead(filePath); ???????????????long dataLengthToRead = iStream.Length;//获取下载的文件总大小 ???????????????Response.ContentType = "application/octet-stream"; ???????????????Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName)); ???????????????while (dataLengthToRead > 0 && Response.IsClientConnected) ???????????????{ ???????????????????int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小 ???????????????????Response.OutputStream.Write(buffer, 0, lengthRead); ???????????????????Response.Flush(); ???????????????????dataLengthToRead = dataLengthToRead - lengthRead; ???????????????} ???????????????Response.Close(); ???????????} ???????}