asp.net文件下载

switch (Convert.ToInt32(Request["type"])) { //流方式下载 方法一 case 1: string filename = "123.pdf"; string filepath = Server.MapPath("upload/123.pdf"); FileStream fs = new FileStream(filepath, 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", "p_w_upload; filename=" + HttpUtility.UrlEncode(filename, System.Text.Encoding.Default)); Response.BinaryWrite(bytes); Response.Flush(); break; case 2://方法2 Response.ContentType = "application/x-zip-compressed"; Response.AddHeader("Content-Disposition", "p_w_upload;filename=z.zip"); string filename2 = Server.MapPath("upload/aaa.zip"); Response.TransmitFile(filename2); break; case 3://方法三 string fileName = "123.pdf"; string filePath = Server.MapPath("upload/123.pdf"); FileInfo fileInfo = new FileInfo(filePath); Response.Clear(); Response.ClearContent(); Response.ClearHeaders(); Response.AddHeader("Content-Disposition", "p_w_upload;filename=" + fileName); Response.AddHeader("Content-Length", fileInfo.Length.ToString()); Response.AddHeader("Content-Transfer-Encoding", "binary"); Response.ContentType = "application/octet-stream"; Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312"); Response.WriteFile(fileInfo.FullName); Response.Flush(); break; case 4://分块下载，方法四 string fileName4 = "123.pdf"; string filePath5 = Server.MapPath("upload/123.pdf"); System.IO.FileInfo fileInfo4 = new System.IO.FileInfo(filePath5); if (fileInfo4.Exists == true) { const long ChunkSize = 1024000;//每次读取100K byte[] buffer = new byte[ChunkSize]; Response.Clear(); System.IO.FileStream iStream = System.IO.File.OpenRead(filePath5); long dataLengthToRead = iStream.Length;//获取文件长度 Response.ContentType = "application/octet-stream"; Response.AddHeader("Content-Disposition", "p_w_upload; filename=" + HttpUtility.UrlEncode(fileName4)); while (dataLengthToRead > 0 && Response.IsClientConnected) { int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize)); Response.OutputStream.Write(buffer, 0, lengthRead); Response.Flush(); dataLengthToRead = dataLengthToRead - lengthRead; } Response.Close(); } break; default: Response.Write("ddd"); break; } Response.End(); 下载文件方法封装，怎样根据文件的扩展名下载文件（如没有扩展名，文件打开有可能出现乱码） void DownloadFile(string filename) { string saveFileName = "123.xls"; int intStart = filename.LastIndexOf("\\") + 1; saveFileName = filename.Substring(intStart, filename.Length - intStart); System.IO.FileInfo fi = new System.IO.FileInfo(filename); string fileextname = fi.Extension; string DEFAULT_CONTENT_TYPE = "application/unknown"; RegistryKey regkey, fileextkey; string filecontenttype; try { regkey = Registry.ClassesRoot; fileextkey = regkey.OpenSubKey(fileextname); filecontenttype = fileextkey.GetValue("Content Type", DEFAULT_CONTENT_TYPE).ToString(); } catch { filecontenttype = DEFAULT_CONTENT_TYPE; } Response.Clear(); Response.Charset = "utf-8"; Response.Buffer = true; this.EnableViewState = false; Response.ContentEncoding = System.Text.Encoding.UTF8; Response.AppendHeader("Content-Disposition", "p_w_upload;filename=" + saveFileName); Response.ContentType = filecontenttype; Response.WriteFile(filename); Response.Flush(); Response.Close(); Response.End(); }