if (file.Exists)

　　{

　　Response.Clear();

　　Response.Charset = "GB2312";

　　Response.ContentEncoding = System.Text.Encoding.UTF8;

　　Response.AddHeader("Content-Disposition", "attachment;filename=" + Server.UrlEncode(file.Name));

　　Response.AddHeader("Conten-Length", file.Length.ToString());

　　Response.ContentType = "application/ms-excel";

　　Response.WriteFile(file.FullName);

　　Response.End();

　　}

　　下面是更详细的ContentType

　　'ez' => 'application/andrew-inset',

　　'hqx' => 'application/mac-binhex40',

　　'cpt' => 'application/mac-compactpro',

　　'doc' => 'application/msword',

　　'bin' => 'application/octet-stream',

　　'dms' => 'application/octet-stream',

　　'lha' => 'application/octet-stream',

　　'lzh' => 'application/octet-stream',

　　'exe' => 'application/octet-stream',

　　'class' => 'application/octet-stream',

　　'so' => 'application/octet-stream',

　　'dll' => 'application/octet-stream',

　　'oda' => 'application/oda',

　　'pdf' => 'application/pdf',

　　'ai' => 'application/postscript',

　　'eps' => 'application/postscript',

　　'ps' => 'application/postscript',

　　'smi' => 'application/smil',

　　'smil' => 'application/smil',

　　'mif' => 'application/vnd.mif',

　　'xls' => 'application/vnd.ms-excel',

　　'ppt' => 'application/vnd.ms-powerpoint',

　　'wbxml' => 'application/vnd.wap.wbxml',

　　'wmlc' => 'application/vnd.wap.wmlc',

　　'wmlsc' => 'application/vnd.wap.wmlscriptc',

　　'bcpio' => 'application/x-bcpio',

　　'vcd' => 'application/x-cdlink',

　　'pgn' => 'application/x-chess-pgn',

　　'cpio' => 'application/x-cpio',

　　'csh' => 'application/x-csh',

　　'dcr' => 'application/x-director',

　　'dir' => 'application/x-director','dxr' => 'application/x-director',

　　'dvi' => 'application/x-dvi',

　　'spl' => 'application/x-futuresplash',

　　'gtar' => 'application/x-gtar',

　　'hdf' => 'application/x-hdf',

　　'js' => 'application/x-javascript',

　　'skp' => 'application/x-koan',

　　'skd' => 'application/x-koan',

　　'skt' => 'application/x-koan',

　　'skm' => 'application/x-koan',

　　'latex' => 'application/x-latex',

　　'nc' => 'application/x-netcdf',

　　'cdf' => 'application/x-netcdf',

　　'sh' => 'application/x-sh',

　　'shar' => 'application/x-shar',

　　'swf' => 'application/x-shockwave-flash',

　　'sit' => 'application/x-stuffit',

　　'sv4cpio' => 'application/x-sv4cpio',

　　'sv4crc' => 'application/x-sv4crc',

　　'tar' => 'application/x-tar',

　　'tcl' => 'application/x-tcl',

　　'tex' => 'application/x-tex',

　　'texinfo' => 'application/x-texinfo',

　　'texi' => 'application/x-texinfo',

　　't' => 'application/x-troff',

　　'tr' => 'application/x-troff',

　　'roff' => 'application/x-troff',

　　'man' => 'application/x-troff-man',

　　'me' => 'application/x-troff-me',

　　'ms' => 'application/x-troff-ms',

　　'ustar' => 'application/x-ustar',

　　'src' => 'application/x-wais-source',