这种方法在受到.NET版本和访问注册表权限时，是最佳解决方案，虽然代码看起来很多，不过下面的类直接拿走用就可以了。

public class FileContentType

 {

     private static IDictionary<string, string> _mappings = new Dictionary<string,string>(StringComparer.InvariantCultureIgnoreCase) {

 

     #region Big freaking list of mime types

     // combination of values from Windows 7 Registry and

     // from C:\Windows\System32\inetsrv\config\applicationHost.config

     // some added, including .7z and .dat

     {".323", "text/h323"},

     {".3g2", "video/3gpp2"},

     {".3gp", "video/3gpp"},

     {".3gp2", "video/3gpp2"},

     {".3gpp", "video/3gpp"},

     {".7z", "application/x-7z-compressed"},

     {".aa", "audio/audible"},

     {".AAC", "audio/aac"},

     {".aaf", "application/octet-stream"},

     {".aax", "audio/vnd.audible.aax"},

     {".ac3", "audio/ac3"},

     {".aca", "application/octet-stream"},

     {".accda", "application/msaccess.addin"},

     {".accdb", "application/msaccess"},

     {".accdc", "application/msaccess.cab"},

     {".accde", "application/msaccess"},

     {".accdr", "application/msaccess.runtime"},

     {".accdt", "application/msaccess"},

     {".accdw", "application/msaccess.webapplication"},

     {".accft", "application/msaccess.ftemplate"},

     {".acx", "application/internet-property-stream"},

     {".AddIn", "text/xml"},

     {".ade", "application/msaccess"},

     {".adobebridge", "application/x-bridge-url"},

     {".adp", "application/msaccess"},

     {".ADT", "audio/vnd.dlna.adts"},

     {".ADTS", "audio/aac"},

     {".afm", "application/octet-stream"},

     {".ai", "application/postscript"},

     {".aif", "audio/x-aiff"},

     {".aifc", "audio/aiff"},

     {".aiff", "audio/aiff"},

     {".air", "application/vnd.adobe.air-application-installer-package+zip"},

     {".amc", "application/x-mpeg"},

     {".application", "application/x-ms-application"},

     {".art", "image/x-jg"},

     {".asa", "application/xml"},

     {".asax", "application/xml"},

     {".ascx", "application/xml"},

     {".asd", "application/octet-stream"},

     {".asf", "video/x-ms-asf"},

     {".ashx", "application/xml"},

     {".asi", "application/octet-stream"},

     {".asm", "text/plain"},

     {".asmx", "application/xml"},

     {".aspx", "application/xml"},

     {".asr", "video/x-ms-asf"},

     {".asx", "video/x-ms-asf"},

     {".atom", "application/atom+xml"},

     {".au", "audio/basic"},

     {".avi", "video/x-msvideo"},

     {".axs", "application/olescript"},

     {".bas", "text/plain"},

     {".bcpio", "application/x-bcpio"},

     {".bin", "application/octet-stream"},

     {".bmp", "image/bmp"},

     {".c", "text/plain"},

     {".cab", "application/octet-stream"},

     {".caf", "audio/x-caf"},

     {".calx", "application/vnd.ms-office.calx"},

     {".cat", "application/vnd.ms-pki.seccat"},

     {".cc", "text/plain"},

     {".cd", "text/plain"},

     {".cdda", "audio/aiff"},

     {".cdf", "application/x-cdf"},

     {".cer", "application/x-x509-ca-cert"},

     {".chm", "application/octet-stream"},

     {".class", "application/x-java-applet"},

     {".clp", "application/x-msclip"},

     {".cmx", "image/x-cmx"},

     {".cnf", "text/plain"},

     {".cod", "image/cis-cod"},

     {".config", "application/xml"},

     {".contact", "text/x-ms-contact"},

     {".coverage", "application/xml"},

     {".cpio", "application/x-cpio"},

     {".cpp", "text/plain"},

     {".crd", "application/x-mscardfile"},

     {".crl", "application/pkix-crl"},

     {".crt", "application/x-x509-ca-cert"},

     {".cs", "text/plain"},

     {".csdproj", "text/plain"},

     {".csh", "application/x-csh"},

     {".csproj", "text/plain"},

     {".css", "text/css"},

     {".csv", "text/csv"},

     {".cur", "application/octet-stream"},

     {".cxx", "text/plain"},

     {".dat", "application/octet-stream"},

     {".datasource", "application/xml"},

     {".dbproj", "text/plain"},

     {".dcr", "application/x-director"},

     {".def", "text/plain"},

     {".deploy", "application/octet-stream"},

     {".der", "application/x-x509-ca-cert"},

     {".dgml", "application/xml"},

     {".dib", "image/bmp"},

     {".dif", "video/x-dv"},

     {".dir", "application/x-director"},

     {".disco", "text/xml"},

     {".dll", "application/x-msdownload"},

     {".dll.config", "text/xml"},

     {".dlm", "text/dlm"},

     {".doc", "application/msword"},

     {".docm", "application/vnd.ms-word.document.macroEnabled.12"},

     {".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},

     {".dot", "application/msword"},

     {".dotm", "application/vnd.ms-word.template.macroEnabled.12"},

     {".dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template"},

     {".dsp", "application/octet-stream"},

     {".dsw", "text/plain"},

     {".dtd", "text/xml"},

     {".dtsConfig", "text/xml"},

     {".dv", "video/x-dv"},

     {".dvi", "application/x-dvi"},

     {".dwf", "drawing/x-dwf"},

     {".dwp", "application/octet-stream"},

     {".dxr", "application/x-director"},

     {".eml", "message/rfc822"},

     {".emz", "application/octet-stream"},

     {".eot", "application/octet-stream"},

     {".eps", "application/postscript"},

     {".etl", "application/etl"},

     {".etx", "text/x-setext"},

     {".evy", "application/envoy"},

     {".exe", "application/octet-stream"},

     {".exe.config", "text/xml"},

     {".fdf", "application/vnd.fdf"},

     {".fif", "application/fractals"},

     {".filters", "Application/xml"},

     {".fla", "application/octet-stream"},

     {".flr", "x-world/x-vrml"},

     {".flv", "video/x-flv"},

     {".fsscript", "application/fsharp-script"},

     {".fsx", "application/fsharp-script"},

     {".generictest", "application/xml"},

     {".gif", "image/gif"},

     {".group", "text/x-ms-group"},

     {".gsm", "audio/x-gsm"},

     {".gtar", "application/x-gtar"},

     {".gz", "application/x-gzip"},

     {".h", "text/plain"},

     {".hdf", "application/x-hdf"},

     {".hdml", "text/x-hdml"},

     {".hhc", "application/x-oleobject"},

     {".hhk", "application/octet-stream"},

     {".hhp", "application/octet-stream"},

     {".hlp", "application/winhlp"},

     {".hpp", "text/plain"},

     {".hqx", "application/mac-binhex40"},

     {".hta", "application/hta"},

     {".htc", "text/x-component"},

     {".htm", "text/html"},

     {".html", "text/html"},

     {".htt", "text/webviewhtml"},

     {".hxa", "application/xml"},

     {".hxc", "application/xml"},

     {".hxd", "application/octet-stream"},

     {".hxe", "application/xml"},

     {".hxf", "application/xml"},

     {".hxh", "application/octet-stream"},

     {".hxi", "application/octet-stream"},

     {".hxk", "application/xml"},

     {".hxq", "application/octet-stream"},

     {".hxr", "application/octet-stream"},

     {".hxs", "application/octet-stream"},

     {".hxt", "text/html"},

     {".hxv", "application/xml"},

     {".hxw", "application/octet-stream"},

     {".hxx", "text/plain"},

     {".i", "text/plain"},

     {".ico", "image/x-icon"},

     {".ics", "application/octet-stream"},

     {".idl", "text/plain"},

     {".ief", "image/ief"},

     {".iii", "application/x-iphone"},

     {".inc", "text/plain"},

     {".inf", "application/octet-stream"},

     {".inl", "text/plain"},

     {".ins", "application/x-internet-signup"},

     {".ipa", "application/x-itunes-ipa"},

     {".ipg", "application/x-itunes-ipg"},

     {".ipproj", "text/plain"},

     {".ipsw", "application/x-itunes-ipsw"},

     {".iqy", "text/x-ms-iqy"},

     {".isp", "application/x-internet-signup"},

     {".ite", "application/x-itunes-ite"},

     {".itlp", "application/x-itunes-itlp"},

     {".itms", "application/x-itunes-itms"},

     {".itpc", "application/x-itunes-itpc"},

     {".IVF", "video/x-ivf"},

     {".jar", "application/java-archive"},

     {".java", "application/octet-stream"},

     {".jck", "application/liquidmotion"},

     {".jcz", "application/liquidmotion"},

     {".jfif", "image/pjpeg"},

     {".jnlp", "application/x-java-jnlp-file"},

     {".jpb", "application/octet-stream"},

     {".jpe", "image/jpeg"},

     {".jpeg", "image/jpeg"},

     {".jpg", "image/jpeg"},

     {".js", "application/x-javascript"},

     {".jsx", "text/jscript"},

     {".jsxbin", "text/plain"},

     {".latex", "application/x-latex"},

     {".library-ms", "application/windows-library+xml"},

     {".lit", "application/x-ms-reader"},

     {".loadtest", "application/xml"},

     {".lpk", "application/octet-stream"},

     {".lsf", "video/x-la-asf"},

     {".lst", "text/plain"},

     {".lsx", "video/x-la-asf"},

     {".lzh", "application/octet-stream"},

     {".m13", "application/x-msmediaview"},

     {".m14", "application/x-msmediaview"},

     {".m1v", "video/mpeg"},

     {".m2t", "video/vnd.dlna.mpeg-tts"},

     {".m2ts", "video/vnd.dlna.mpeg-tts"},

     {".m2v", "video/mpeg"},

     {".m3u", "audio/x-mpegurl"},

     {".m3u8", "audio/x-mpegurl"},

     {".m4a", "audio/m4a"},

     {".m4b", "audio/m4b"},

     {".m4p", "audio/m4p"},

     {".m4r", "audio/x-m4r"},

     {".m4v", "video/x-m4v"},

     {".mac", "image/x-macpaint"},

     {".mak", "text/plain"},

     {".man", "application/x-troff-man"},

     {".manifest", "application/x-ms-manifest"},

     {".map", "text/plain"},

     {".master", "application/xml"},

     {".mda", "application/msaccess"},

     {".mdb", "application/x-msaccess"},

     {".mde", "application/msaccess"},

     {".mdp", "application/octet-stream"},

     {".me", "application/x-troff-me"},

     {".mfp", "application/x-shockwave-flash"},

     {".mht", "message/rfc822"},

     {".mhtml", "message/rfc822"},

     {".mid", "audio/mid"},

     {".midi", "audio/mid"},

     {".mix", "application/octet-stream"},

     {".mk", "text/plain"},

     {".mmf", "application/x-smaf"},

     {".mno", "text/xml"},

     {".mny", "application/x-msmoney"},

     {".mod", "video/mpeg"},

     {".mov", "video/quicktime"},

     {".movie", "video/x-sgi-movie"},

     {".mp2", "video/mpeg"},

     {".mp2v", "video/mpeg"},

     {".mp3", "audio/mpeg"},

     {".mp4", "video/mp4"},

     {".mp4v", "video/mp4"},

     {".mpa", "video/mpeg"},

     {".mpe", "video/mpeg"},

     {".mpeg", "video/mpeg"},

     {".mpf", "application/vnd.ms-mediapackage"},

     {".mpg", "video/mpeg"},

     {".mpp", "application/vnd.ms-project"},

     {".mpv2", "video/mpeg"},

     {".mqv", "video/quicktime"},

     {".ms", "application/x-troff-ms"},

     {".msi", "application/octet-stream"},

     {".mso", "application/octet-stream"},

     {".mts", "video/vnd.dlna.mpeg-tts"},

     {".mtx", "application/xml"},

     {".mvb", "application/x-msmediaview"},

     {".mvc", "application/x-miva-compiled"},

     {".mxp", "application/x-mmxp"},

     {".nc", "application/x-netcdf"},

     {".nsc", "video/x-ms-asf"},

     {".nws", "message/rfc822"},

     {".ocx", "application/octet-stream"},

     {".oda", "application/oda"},

     {".odc", "text/x-ms-odc"},

     {".odh", "text/plain"},

     {".odl", "text/plain"},

     {".odp", "application/vnd.oasis.opendocument.presentation"},

     {".ods", "application/oleobject"},

     {".odt", "application/vnd.oasis.opendocument.text"},

     {".one", "application/onenote"},

     {".onea", "application/onenote"},

     {".onepkg", "application/onenote"},

     {".onetmp", "application/onenote"},

     {".onetoc", "application/onenote"},

     {".onetoc2", "application/onenote"},

     {".orderedtest", "application/xml"},

     {".osdx", "application/opensearchdescription+xml"},

     {".p10", "application/pkcs10"},

     {".p12", "application/x-pkcs12"},

     {".p7b", "application/x-pkcs7-certificates"},

     {".p7c", "application/pkcs7-mime"},

     {".p7m", "application/pkcs7-mime"},

     {".p7r", "application/x-pkcs7-certreqresp"},

     {".p7s", "application/pkcs7-signature"},

     {".pbm", "image/x-portable-bitmap"},

     {".pcast", "application/x-podcast"},

     {".pct", "image/pict"},

     {".pcx", "application/octet-stream"},

     {".pcz", "application/octet-stream"},

     {".pdf", "application/pdf"},

     {".pfb", "application/octet-stream"},

     {".pfm", "application/octet-stream"},

     {".pfx", "application/x-pkcs12"},

     {".pgm", "image/x-portable-graymap"},

     {".pic", "image/pict"},

     {".pict", "image/pict"},

     {".pkgdef", "text/plain"},

     {".pkgundef", "text/plain"},

     {".pko", "application/vnd.ms-pki.pko"},

     {".pls", "audio/scpls"},

     {".pma", "application/x-perfmon"},

     {".pmc", "application/x-perfmon"},

     {".pml", "application/x-perfmon"},

     {".pmr", "application/x-perfmon"},

     {".pmw", "application/x-perfmon"},

     {".png", "image/png"},

     {".pnm", "image/x-portable-anymap"},

     {".pnt", "image/x-macpaint"},

     {".pntg", "image/x-macpaint"},

     {".pnz", "image/png"},

     {".pot", "application/vnd.ms-powerpoint"},

     {".potm", "application/vnd.ms-powerpoint.template.macroEnabled.12"},

     {".potx", "application/vnd.openxmlformats-officedocument.presentationml.template"},

     {".ppa", "application/vnd.ms-powerpoint"},

     {".ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12"},

     {".ppm", "image/x-portable-pixmap"},

     {".pps", "application/vnd.ms-powerpoint"},

     {".ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12"},

     {".ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow"},

     {".ppt", "application/vnd.ms-powerpoint"},

     {".pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12"},

     {".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"},

     {".prf", "application/pics-rules"},

     {".prm", "application/octet-stream"},

     {".prx", "application/octet-stream"},

     {".ps", "application/postscript"},

     {".psc1", "application/PowerShell"},

     {".psd", "application/octet-stream"},

     {".psess", "application/xml"},

     {".psm", "application/octet-stream"},

     {".psp", "application/octet-stream"},

     {".pub", "application/x-mspublisher"},

     {".pwz", "application/vnd.ms-powerpoint"},

     {".qht", "text/x-html-insertion"},

     {".qhtm", "text/x-html-insertion"},

     {".qt", "video/quicktime"},

     {".qti", "image/x-quicktime"},

     {".qtif", "image/x-quicktime"},

     {".qtl", "application/x-quicktimeplayer"},

     {".qxd", "application/octet-stream"},

     {".ra", "audio/x-pn-realaudio"},

     {".ram", "audio/x-pn-realaudio"},

     {".rar", "application/octet-stream"},

     {".ras", "image/x-cmu-raster"},

     {".rat", "application/rat-file"},

     {".rc", "text/plain"},

     {".rc2", "text/plain"},

     {".rct", "text/plain"},

     {".rdlc", "application/xml"},

     {".resx", "application/xml"},

     {".rf", "image/vnd.rn-realflash"},

     {".rgb", "image/x-rgb"},

     {".rgs", "text/plain"},

     {".rm", "application/vnd.rn-realmedia"},

     {".rmi", "audio/mid"},

     {".rmp", "application/vnd.rn-rn_music_package"},

     {".roff", "application/x-troff"},

     {".rpm", "audio/x-pn-realaudio-plugin"},

     {".rqy", "text/x-ms-rqy"},

     {".rtf", "application/rtf"},

     {".rtx", "text/richtext"},

     {".ruleset", "application/xml"},

     {".s", "text/plain"},

     {".safariextz", "application/x-safari-safariextz"},

     {".scd", "application/x-msschedule"},

     {".sct", "text/scriptlet"},

     {".sd2", "audio/x-sd2"},

     {".sdp", "application/sdp"},

     {".sea", "application/octet-stream"},

     {".searchConnector-ms", "application/windows-search-connector+xml"},

     {".setpay", "application/set-payment-initiation"},

     {".setreg", "application/set-registration-initiation"},

     {".settings", "application/xml"},

     {".sgimb", "application/x-sgimb"},

     {".sgml", "text/sgml"},

     {".sh", "application/x-sh"},

     {".shar", "application/x-shar"},

     {".shtml", "text/html"},

     {".sit", "application/x-stuffit"},

     {".sitemap", "application/xml"},

     {".skin", "application/xml"},

     {".sldm", "application/vnd.ms-powerpoint.slide.macroEnabled.12"},

     {".sldx", "application/vnd.openxmlformats-officedocument.presentationml.slide"},

     {".slk", "application/vnd.ms-excel"},

     {".sln", "text/plain"},

     {".slupkg-ms", "application/x-ms-license"},

     {".smd", "audio/x-smd"},

     {".smi", "application/octet-stream"},

     {".smx", "audio/x-smd"},

     {".smz", "audio/x-smd"},

     {".snd", "audio/basic"},

     {".snippet", "application/xml"},

     {".snp", "application/octet-stream"},

     {".sol", "text/plain"},

     {".sor", "text/plain"},

     {".spc", "application/x-pkcs7-certificates"},

     {".spl", "application/futuresplash"},

     {".src", "application/x-wais-source"},

     {".srf", "text/plain"},

     {".SSISDeploymentManifest", "text/xml"},

     {".ssm", "application/streamingmedia"},

     {".sst", "application/vnd.ms-pki.certstore"},

     {".stl", "application/vnd.ms-pki.stl"},

     {".sv4cpio", "application/x-sv4cpio"},

     {".sv4crc", "application/x-sv4crc"},

     {".svc", "application/xml"},

     {".swf", "application/x-shockwave-flash"},

     {".t", "application/x-troff"},

     {".tar", "application/x-tar"},

     {".tcl", "application/x-tcl"},

     {".testrunconfig", "application/xml"},

     {".testsettings", "application/xml"},

     {".tex", "application/x-tex"},

     {".texi", "application/x-texinfo"},

     {".texinfo", "application/x-texinfo"},

     {".tgz", "application/x-compressed"},

     {".thmx", "application/vnd.ms-officetheme"},

     {".thn", "application/octet-stream"},

     {".tif", "image/tiff"},

     {".tiff", "image/tiff"},

     {".tlh", "text/plain"},

     {".tli", "text/plain"},

     {".toc", "application/octet-stream"},

     {".tr", "application/x-troff"},

     {".trm", "application/x-msterminal"},

     {".trx", "application/xml"},

     {".ts", "video/vnd.dlna.mpeg-tts"},

     {".tsv", "text/tab-separated-values"},

     {".ttf", "application/octet-stream"},

     {".tts", "video/vnd.dlna.mpeg-tts"},

     {".txt", "text/plain"},

     {".u32", "application/octet-stream"},

     {".uls", "text/iuls"},

     {".user", "text/plain"},

     {".ustar", "application/x-ustar"},

     {".vb", "text/plain"},

     {".vbdproj", "text/plain"},

     {".vbk", "video/mpeg"},

     {".vbproj", "text/plain"},

     {".vbs", "text/vbscript"},

     {".vcf", "text/x-vcard"},

     {".vcproj", "Application/xml"},

     {".vcs", "text/plain"},

     {".vcxproj", "Application/xml"},

     {".vddproj", "text/plain"},

     {".vdp", "text/plain"},

     {".vdproj", "text/plain"},

     {".vdx", "application/vnd.ms-visio.viewer"},

     {".vml", "text/xml"},

     {".vscontent", "application/xml"},

     {".vsct", "text/xml"},

     {".vsd", "application/vnd.visio"},

     {".vsi", "application/ms-vsi"},

     {".vsix", "application/vsix"},

     {".vsixlangpack", "text/xml"},

     {".vsixmanifest", "text/xml"},

     {".vsmdi", "application/xml"},

     {".vspscc", "text/plain"},

     {".vss", "application/vnd.visio"},

     {".vsscc", "text/plain"},

     {".vssettings", "text/xml"},

     {".vssscc", "text/plain"},

     {".vst", "application/vnd.visio"},

     {".vstemplate", "text/xml"},

     {".vsto", "application/x-ms-vsto"},

     {".vsw", "application/vnd.visio"},

     {".vsx", "application/vnd.visio"},

     {".vtx", "application/vnd.visio"},

     {".wav", "audio/wav"},

     {".wave", "audio/wav"},

     {".wax", "audio/x-ms-wax"},

     {".wbk", "application/msword"},

     {".wbmp", "image/vnd.wap.wbmp"},

     {".wcm", "application/vnd.ms-works"},

     {".wdb", "application/vnd.ms-works"},

     {".wdp", "image/vnd.ms-photo"},

     {".webarchive", "application/x-safari-webarchive"},

     {".webtest", "application/xml"},

     {".wiq", "application/xml"},

     {".wiz", "application/msword"},

     {".wks", "application/vnd.ms-works"},

     {".WLMP", "application/wlmoviemaker"},

     {".wlpginstall", "application/x-wlpg-detect"},

     {".wlpginstall3", "application/x-wlpg3-detect"},

     {".wm", "video/x-ms-wm"},

     {".wma", "audio/x-ms-wma"},

     {".wmd", "application/x-ms-wmd"},

     {".wmf", "application/x-msmetafile"},

     {".wml", "text/vnd.wap.wml"},

     {".wmlc", "application/vnd.wap.wmlc"},

     {".wmls", "text/vnd.wap.wmlscript"},

     {".wmlsc", "application/vnd.wap.wmlscriptc"},

     {".wmp", "video/x-ms-wmp"},

     {".wmv", "video/x-ms-wmv"},

     {".wmx", "video/x-ms-wmx"},

     {".wmz", "application/x-ms-wmz"},

     {".wpl", "application/vnd.ms-wpl"},

     {".wps", "application/vnd.ms-works"},

     {".wri", "application/x-mswrite"},

     {".wrl", "x-world/x-vrml"},

     {".wrz", "x-world/x-vrml"},

     {".wsc", "text/scriptlet"},

     {".wsdl", "text/xml"},

     {".wvx", "video/x-ms-wvx"},

     {".x", "application/directx"},

     {".xaf", "x-world/x-vrml"},

     {".xaml", "application/xaml+xml"},

     {".xap", "application/x-silverlight-app"},

     {".xbap", "application/x-ms-xbap"},

     {".xbm", "image/x-xbitmap"},

     {".xdr", "text/plain"},

     {".xht", "application/xhtml+xml"},

     {".xhtml", "application/xhtml+xml"},

     {".xla", "application/vnd.ms-excel"},

     {".xlam", "application/vnd.ms-excel.addin.macroEnabled.12"},

     {".xlc", "application/vnd.ms-excel"},

     {".xld", "application/vnd.ms-excel"},

     {".xlk", "application/vnd.ms-excel"},

     {".xll", "application/vnd.ms-excel"},

     {".xlm", "application/vnd.ms-excel"},

     {".xls", "application/vnd.ms-excel"},

     {".xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12"},

     {".xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12"},

     {".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},

     {".xlt", "application/vnd.ms-excel"},

     {".xltm", "application/vnd.ms-excel.template.macroEnabled.12"},

     {".xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template"},

     {".xlw", "application/vnd.ms-excel"},

     {".xml", "text/xml"},

     {".xmta", "application/xml"},

     {".xof", "x-world/x-vrml"},

     {".XOML", "text/plain"},

     {".xpm", "image/x-xpixmap"},

     {".xps", "application/vnd.ms-xpsdocument"},

     {".xrm-ms", "text/xml"},

     {".xsc", "application/xml"},

     {".xsd", "text/xml"},

     {".xsf", "text/xml"},

     {".xsl", "text/xml"},

     {".xslt", "text/xml"},

     {".xsn", "application/octet-stream"},

     {".xss", "application/xml"},

     {".xtp", "application/octet-stream"},

     {".xwd", "image/x-xwindowdump"},

     {".z", "application/x-compress"},

     {".zip", "application/x-zip-compressed"},

     #endregion

 

     };

 

     public static string GetMimeType(string extension)

     {

         if (extension == null)

         {

             throw new ArgumentNullException("extension");

         }

 

         if (!extension.StartsWith("."))

         {

             extension = "." + extension;

         }

 

         string mime;

 

         return _mappings.TryGetValue(extension, out mime) ? mime : "application/octet-stream";

     }

 }