【aspnetcore】让aspnetcore支持less文件

第一步：新建文件 CustomerFileExtensionContentTypeProvider

namespace xxx
{
    public class CustomerFileExtensionContentTypeProvider : FileExtensionContentTypeProvider
    {
        public CustomerFileExtensionContentTypeProvider() :
            base((IDictionary<string, string>) new Dictionary<string, string>(
                (IEqualityComparer<string>) StringComparer.OrdinalIgnoreCase)
            {
                {
                    ".323",
                    "text/h323"
                },
                {
                    ".3g2",
                    "video/3gpp2"
                },
                {
                    ".3gp2",
                    "video/3gpp2"
                },
                {
                    ".3gp",
                    "video/3gpp"
                },
                {
                    ".3gpp",
                    "video/3gpp"
                },
                {
                    ".aac",
                    "audio/aac"
                },
                {
                    ".aaf",
                    "application/octet-stream"
                },
                {
                    ".aca",
                    "application/octet-stream"
                },
                {
                    ".accdb",
                    "application/msaccess"
                },
                {
                    ".accde",
                    "application/msaccess"
                },
                {
                    ".accdt",
                    "application/msaccess"
                },
                {
                    ".acx",
                    "application/internet-property-stream"
                },
                {
                    ".adt",
                    "audio/vnd.dlna.adts"
                },
                {
                    ".adts",
                    "audio/vnd.dlna.adts"
                },
                {
                    ".afm",
                    "application/octet-stream"
                },
                {
                    ".ai",
                    "application/postscript"
                },
                {
                    ".aif",
                    "audio/x-aiff"
                },
                {
                    ".aifc",
                    "audio/aiff"
                },
                {
                    ".aiff",
                    "audio/aiff"
                },
                {
                    ".appcache",
                    "text/cache-manifest"
                },
                {
                    ".application",
                    "application/x-ms-application"
                },
                {
                    ".art",
                    "image/x-jg"
                },
                {
                    ".asd",
                    "application/octet-stream"
                },
                {
                    ".asf",
                    "video/x-ms-asf"
                },
                {
                    ".asi",
                    "application/octet-stream"
                },
                {
                    ".asm",
                    "text/plain"
                },
                {
                    ".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/vnd.ms-cab-compressed"
                },
                {
                    ".calx",
                    "application/vnd.ms-office.calx"
                },
                {
                    ".cat",
                    "application/vnd.ms-pki.seccat"
                },
                {
                    ".cdf",
                    "application/x-cdf"
                },
                {
                    ".chm",
                    "application/octet-stream"
                },
                {
                    ".class",
                    "application/x-java-applet"
                },
                {
                    ".clp",
                    "application/x-msclip"
                },
                {
                    ".cmx",
                    "image/x-cmx"
                },
                {
                    ".cnf",
                    "text/plain"
                },
                {
                    ".cod",
                    "image/cis-cod"
                },
                {
                    ".cpio",
                    "application/x-cpio"
                },
                {
                    ".cpp",
                    "text/plain"
                },
                {
                    ".crd",
                    "application/x-mscardfile"
                },
                {
                    ".crl",
                    "application/pkix-crl"
                },
                {
                    ".crt",
                    "application/x-x509-ca-cert"
                },
                {
                    ".csh",
                    "application/x-csh"
                },
                {
                    ".css",
                    "text/css"
                },
                {
                    ".csv",
                    "application/octet-stream"
                },
                {
                    ".cur",
                    "application/octet-stream"
                },
                {
                    ".dcr",
                    "application/x-director"
                },
                {
                    ".deploy",
                    "application/octet-stream"
                },
                {
                    ".der",
                    "application/x-x509-ca-cert"
                },
                {
                    ".dib",
                    "image/bmp"
                },
                {
                    ".dir",
                    "application/x-director"
                },
                {
                    ".disco",
                    "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"
                },
                {
                    ".dtd",
                    "text/xml"
                },
                {
                    ".dvi",
                    "application/x-dvi"
                },
                {
                    ".dvr-ms",
                    "video/x-ms-dvr"
                },
                {
                    ".dwf",
                    "drawing/x-dwf"
                },
                {
                    ".dwp",
                    "application/octet-stream"
                },
                {
                    ".dxr",
                    "application/x-director"
                },
                {
                    ".eml",
                    "message/rfc822"
                },
                {
                    ".emz",
                    "application/octet-stream"
                },
                {
                    ".eot",
                    "application/vnd.ms-fontobject"
                },
                {
                    ".eps",
                    "application/postscript"
                },
                {
                    ".etx",
                    "text/x-setext"
                },
                {
                    ".evy",
                    "application/envoy"
                },
                {
                    ".fdf",
                    "application/vnd.fdf"
                },
                {
                    ".fif",
                    "application/fractals"
                },
                {
                    ".fla",
                    "application/octet-stream"
                },
                {
                    ".flr",
                    "x-world/x-vrml"
                },
                {
                    ".flv",
                    "video/x-flv"
                },
                {
                    ".gif",
                    "image/gif"
                },
                {
                    ".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"
                },
                {
                    ".hqx",
                    "application/mac-binhex40"
                },
                {
                    ".hta",
                    "application/hta"
                },
                {
                    ".htc",
                    "text/x-component"
                },
                {
                    ".htm",
                    "text/html"
                },
                {
                    ".html",
                    "text/html"
                },
                {
                    ".htt",
                    "text/webviewhtml"
                },
                {
                    ".hxt",
                    "text/html"
                },
                {
                    ".ical",
                    "text/calendar"
                },
                {
                    ".icalendar",
                    "text/calendar"
                },
                {
                    ".ico",
                    "image/x-icon"
                },
                {
                    ".ics",
                    "text/calendar"
                },
                {
                    ".ief",
                    "image/ief"
                },
                {
                    ".ifb",
                    "text/calendar"
                },
                {
                    ".iii",
                    "application/x-iphone"
                },
                {
                    ".inf",
                    "application/octet-stream"
                },
                {
                    ".ins",
                    "application/x-internet-signup"
                },
                {
                    ".isp",
                    "application/x-internet-signup"
                },
                {
                    ".IVF",
                    "video/x-ivf"
                },
                {
                    ".jar",
                    "application/java-archive"
                },
                {
                    ".java",
                    "application/octet-stream"
                },
                {
                    ".jck",
                    "application/liquidmotion"
                },
                {
                    ".jcz",
                    "application/liquidmotion"
                },
                {
                    ".jfif",
                    "image/pjpeg"
                },
                {
                    ".jpb",
                    "application/octet-stream"
                },
                {
                    ".jpe",
                    "image/jpeg"
                },
                {
                    ".jpeg",
                    "image/jpeg"
                },
                {
                    ".jpg",
                    "image/jpeg"
                },
                {
                    ".js",
                    "application/javascript"
                },
                {
                    ".json",
                    "application/json"
                },
                {
                    ".jsx",
                    "text/jscript"
                },
                {
                    ".latex",
                    "application/x-latex"
                },
                {
                    ".lit",
                    "application/x-ms-reader"
                },
                {
                    ".lpk",
                    "application/octet-stream"
                },
                {
                    ".lsf",
                    "video/x-la-asf"
                },
                {
                    ".lsx",
                    "video/x-la-asf"
                },
                {
                    ".lzh",
                    "application/octet-stream"
                },
                {
                    ".m13",
                    "application/x-msmediaview"
                },
                {
                    ".m14",
                    "application/x-msmediaview"
                },
                {
                    ".m1v",
                    "video/mpeg"
                },
                {
                    ".m2ts",
                    "video/vnd.dlna.mpeg-tts"
                },
                {
                    ".m3u",
                    "audio/x-mpegurl"
                },
                {
                    ".m4a",
                    "audio/mp4"
                },
                {
                    ".m4v",
                    "video/mp4"
                },
                {
                    ".man",
                    "application/x-troff-man"
                },
                {
                    ".manifest",
                    "application/x-ms-manifest"
                },
                {
                    ".map",
                    "text/plain"
                },
                {
                    ".markdown",
                    "text/markdown"
                },
                {
                    ".md",
                    "text/markdown"
                },
                {
                    ".mdb",
                    "application/x-msaccess"
                },
                {
                    ".mdp",
                    "application/octet-stream"
                },
                {
                    ".me",
                    "application/x-troff-me"
                },
                {
                    ".mht",
                    "message/rfc822"
                },
                {
                    ".mhtml",
                    "message/rfc822"
                },
                {
                    ".mid",
                    "audio/mid"
                },
                {
                    ".midi",
                    "audio/mid"
                },
                {
                    ".mix",
                    "application/octet-stream"
                },
                {
                    ".mmf",
                    "application/x-smaf"
                },
                {
                    ".mno",
                    "text/xml"
                },
                {
                    ".mny",
                    "application/x-msmoney"
                },
                {
                    ".mov",
                    "video/quicktime"
                },
                {
                    ".movie",
                    "video/x-sgi-movie"
                },
                {
                    ".mp2",
                    "video/mpeg"
                },
                {
                    ".mp3",
                    "audio/mpeg"
                },
                {
                    ".mp4",
                    "video/mp4"
                },
                {
                    ".mp4v",
                    "video/mp4"
                },
                {
                    ".mpa",
                    "video/mpeg"
                },
                {
                    ".mpe",
                    "video/mpeg"
                },
                {
                    ".mpeg",
                    "video/mpeg"
                },
                {
                    ".mpg",
                    "video/mpeg"
                },
                {
                    ".mpp",
                    "application/vnd.ms-project"
                },
                {
                    ".mpv2",
                    "video/mpeg"
                },
                {
                    ".ms",
                    "application/x-troff-ms"
                },
                {
                    ".msi",
                    "application/octet-stream"
                },
                {
                    ".mso",
                    "application/octet-stream"
                },
                {
                    ".mvb",
                    "application/x-msmediaview"
                },
                {
                    ".mvc",
                    "application/x-miva-compiled"
                },
                {
                    ".nc",
                    "application/x-netcdf"
                },
                {
                    ".nsc",
                    "video/x-ms-asf"
                },
                {
                    ".nws",
                    "message/rfc822"
                },
                {
                    ".ocx",
                    "application/octet-stream"
                },
                {
                    ".oda",
                    "application/oda"
                },
                {
                    ".odc",
                    "text/x-ms-odc"
                },
                {
                    ".ods",
                    "application/oleobject"
                },
                {
                    ".oga",
                    "audio/ogg"
                },
                {
                    ".ogg",
                    "video/ogg"
                },
                {
                    ".ogv",
                    "video/ogg"
                },
                {
                    ".ogx",
                    "application/ogg"
                },
                {
                    ".one",
                    "application/onenote"
                },
                {
                    ".onea",
                    "application/onenote"
                },
                {
                    ".onetoc",
                    "application/onenote"
                },
                {
                    ".onetoc2",
                    "application/onenote"
                },
                {
                    ".onetmp",
                    "application/onenote"
                },
                {
                    ".onepkg",
                    "application/onenote"
                },
                {
                    ".osdx",
                    "application/opensearchdescription+xml"
                },
                {
                    ".otf",
                    "font/otf"
                },
                {
                    ".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"
                },
                {
                    ".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"
                },
                {
                    ".pko",
                    "application/vnd.ms-pki.pko"
                },
                {
                    ".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"
                },
                {
                    ".pnz",
                    "image/png"
                },
                {
                    ".pot",
                    "application/vnd.ms-powerpoint"
                },
                {
                    ".potm",
                    "application/vnd.ms-powerpoint.template.macroEnabled.12"
                },
                {
                    ".potx",
                    "application/vnd.openxmlformats-officedocument.presentationml.template"
                },
                {
                    ".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"
                },
                {
                    ".psd",
                    "application/octet-stream"
                },
                {
                    ".psm",
                    "application/octet-stream"
                },
                {
                    ".psp",
                    "application/octet-stream"
                },
                {
                    ".pub",
                    "application/x-mspublisher"
                },
                {
                    ".qt",
                    "video/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"
                },
                {
                    ".rf",
                    "image/vnd.rn-realflash"
                },
                {
                    ".rgb",
                    "image/x-rgb"
                },
                {
                    ".rm",
                    "application/vnd.rn-realmedia"
                },
                {
                    ".rmi",
                    "audio/mid"
                },
                {
                    ".roff",
                    "application/x-troff"
                },
                {
                    ".rpm",
                    "audio/x-pn-realaudio-plugin"
                },
                {
                    ".rtf",
                    "application/rtf"
                },
                {
                    ".rtx",
                    "text/richtext"
                },
                {
                    ".scd",
                    "application/x-msschedule"
                },
                {
                    ".sct",
                    "text/scriptlet"
                },
                {
                    ".sea",
                    "application/octet-stream"
                },
                {
                    ".setpay",
                    "application/set-payment-initiation"
                },
                {
                    ".setreg",
                    "application/set-registration-initiation"
                },
                {
                    ".sgml",
                    "text/sgml"
                },
                {
                    ".sh",
                    "application/x-sh"
                },
                {
                    ".shar",
                    "application/x-shar"
                },
                {
                    ".sit",
                    "application/x-stuffit"
                },
                {
                    ".sldm",
                    "application/vnd.ms-powerpoint.slide.macroEnabled.12"
                },
                {
                    ".sldx",
                    "application/vnd.openxmlformats-officedocument.presentationml.slide"
                },
                {
                    ".smd",
                    "audio/x-smd"
                },
                {
                    ".smi",
                    "application/octet-stream"
                },
                {
                    ".smx",
                    "audio/x-smd"
                },
                {
                    ".smz",
                    "audio/x-smd"
                },
                {
                    ".snd",
                    "audio/basic"
                },
                {
                    ".snp",
                    "application/octet-stream"
                },
                {
                    ".spc",
                    "application/x-pkcs7-certificates"
                },
                {
                    ".spl",
                    "application/futuresplash"
                },
                {
                    ".spx",
                    "audio/ogg"
                },
                {
                    ".src",
                    "application/x-wais-source"
                },
                {
                    ".ssm",
                    "application/streamingmedia"
                },
                {
                    ".sst",
                    "application/vnd.ms-pki.certstore"
                },
                {
                    ".stl",
                    "application/vnd.ms-pki.stl"
                },
                {
                    ".sv4cpio",
                    "application/x-sv4cpio"
                },
                {
                    ".sv4crc",
                    "application/x-sv4crc"
                },
                {
                    ".svg",
                    "image/svg+xml"
                },
                {
                    ".svgz",
                    "image/svg+xml"
                },
                {
                    ".swf",
                    "application/x-shockwave-flash"
                },
                {
                    ".t",
                    "application/x-troff"
                },
                {
                    ".tar",
                    "application/x-tar"
                },
                {
                    ".tcl",
                    "application/x-tcl"
                },
                {
                    ".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"
                },
                {
                    ".toc",
                    "application/octet-stream"
                },
                {
                    ".tr",
                    "application/x-troff"
                },
                {
                    ".trm",
                    "application/x-msterminal"
                },
                {
                    ".ts",
                    "video/vnd.dlna.mpeg-tts"
                },
                {
                    ".tsv",
                    "text/tab-separated-values"
                },
                {
                    ".ttc",
                    "application/x-font-ttf"
                },
                {
                    ".ttf",
                    "application/x-font-ttf"
                },
                {
                    ".tts",
                    "video/vnd.dlna.mpeg-tts"
                },
                {
                    ".txt",
                    "text/plain"
                },
                {
                    ".u32",
                    "application/octet-stream"
                },
                {
                    ".uls",
                    "text/iuls"
                },
                {
                    ".ustar",
                    "application/x-ustar"
                },
                {
                    ".vbs",
                    "text/vbscript"
                },
                {
                    ".vcf",
                    "text/x-vcard"
                },
                {
                    ".vcs",
                    "text/plain"
                },
                {
                    ".vdx",
                    "application/vnd.ms-visio.viewer"
                },
                {
                    ".vml",
                    "text/xml"
                },
                {
                    ".vsd",
                    "application/vnd.visio"
                },
                {
                    ".vss",
                    "application/vnd.visio"
                },
                {
                    ".vst",
                    "application/vnd.visio"
                },
                {
                    ".vsto",
                    "application/x-ms-vsto"
                },
                {
                    ".vsw",
                    "application/vnd.visio"
                },
                {
                    ".vsx",
                    "application/vnd.visio"
                },
                {
                    ".vtx",
                    "application/vnd.visio"
                },
                {
                    ".wasm",
                    "application/wasm"
                },
                {
                    ".wav",
                    "audio/wav"
                },
                {
                    ".wax",
                    "audio/x-ms-wax"
                },
                {
                    ".wbmp",
                    "image/vnd.wap.wbmp"
                },
                {
                    ".wcm",
                    "application/vnd.ms-works"
                },
                {
                    ".wdb",
                    "application/vnd.ms-works"
                },
                {
                    ".webm",
                    "video/webm"
                },
                {
                    ".webp",
                    "image/webp"
                },
                {
                    ".wks",
                    "application/vnd.ms-works"
                },
                {
                    ".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"
                },
                {
                    ".woff",
                    "application/font-woff"
                },
                {
                    ".woff2",
                    "font/woff2"
                },
                {
                    ".wps",
                    "application/vnd.ms-works"
                },
                {
                    ".wri",
                    "application/x-mswrite"
                },
                {
                    ".wrl",
                    "x-world/x-vrml"
                },
                {
                    ".wrz",
                    "x-world/x-vrml"
                },
                {
                    ".wsdl",
                    "text/xml"
                },
                {
                    ".wtv",
                    "video/x-ms-wtv"
                },
                {
                    ".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"
                },
                {
                    ".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"
                },
                {
                    ".xof",
                    "x-world/x-vrml"
                },
                {
                    ".xpm",
                    "image/x-xpixmap"
                },
                {
                    ".xps",
                    "application/vnd.ms-xpsdocument"
                },
                {
                    ".xsd",
                    "text/xml"
                },
                {
                    ".xsf",
                    "text/xml"
                },
                {
                    ".xsl",
                    "text/xml"
                },
                {
                    ".xslt",
                    "text/xml"
                },
                {
                    ".xsn",
                    "application/octet-stream"
                },
                {
                    ".xtp",
                    "application/octet-stream"
                },
                {
                    ".xwd",
                    "image/x-xwindowdump"
                },
                {
                    ".z",
                    "application/x-compress"
                },
                {
                    ".zip",
                    "application/x-zip-compressed"
                },
                {
                    ".less",
                    "stylesheet/css"
                }
            })
        {
        }
    }
}

第二部：修改startup.cs，在Configure方法内：

app.UseStaticFiles(new StaticFileOptions
{
    ContentTypeProvider = new CustomerFileExtensionContentTypeProvider()
});