blocks|key|325186|text|这取决于您需要MIME类型的目的。通常，对于服务(web应用程序、web服务等)，建议不要使用依赖于操作系统设置的MIME列表，或者仅在无法找到MIME信息的情况下才使用备用列表。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|325187|我认为这也是为什么微软选择将常量MIME类型放在他们的System.Web.MimeMapping类中的原因(不幸的是，无论出于什么原因，它都是内部的)。|offset|length|style|CODE|325188|编辑：|325189|包装器(<=+.NET+3.5)|325190|public+static+class+MimeExtensionHelper
{
++++static+object+locker+=+new+object();
++++static+object+mimeMapping;
++++static+MethodInfo+getMimeMappingMethodInfo;

++++static+MimeExtensionHelper()
++++{
++++++++Type+mimeMappingType+=+Assembly.GetAssembly(typeof(HttpRuntime)).GetType("System.Web.MimeMapping");
++++++++if+(mimeMappingType+==+null)
++++++++++++throw+new+SystemException("Couldnt+find+MimeMapping+type");
++++++++ConstructorInfo+constructorInfo+=+mimeMappingType.GetConstructor(BindingFlags.NonPublic+%7C+BindingFlags.Instance,+null,+Type.EmptyTypes,+null);
++++++++if+(constructorInfo+==+null)
++++++++++++throw+new+SystemException("Couldnt+find+default+constructor+for+MimeMapping");
++++++++mimeMapping+=+constructorInfo.Invoke(null);
++++++++if+(mimeMapping+==+null)
++++++++++++throw+new+SystemException("Couldnt+find+MimeMapping");
++++++++getMimeMappingMethodInfo+=+mimeMappingType.GetMethod("GetMimeMapping",+BindingFlags.Static+%7C+BindingFlags.NonPublic);
++++++++if+(getMimeMappingMethodInfo+==+null)
++++++++++++throw+new+SystemException("Couldnt+find+GetMimeMapping+method");
++++++++if+(getMimeMappingMethodInfo.ReturnType+!=+typeof(string))
++++++++++++throw+new+SystemException("GetMimeMapping+method+has+invalid+return+type");
++++++++if+(getMimeMappingMethodInfo.GetParameters().Length+!=+1+&&+getMimeMappingMethodInfo.GetParameters()[0].ParameterType+!=+typeof(string))
++++++++++++throw+new+SystemException("GetMimeMapping+method+has+invalid+parameters");
++++}
++++public+static+string+GetMimeType(string+filename)
++++{
++++++++lock+(locker)
++++++++++++return+(string)getMimeMappingMethodInfo.Invoke(mimeMapping,+new+object[]+{+filename+});
++++}
}|code-block|syntax|javascript|325191|包装器(.NET+4.0)|325192|public+static+class+MimeExtensionHelper
++++{
++++++++static+object+locker+=+new+object();
++++++++static+object+mimeMapping;
++++++++static+MethodInfo+getMimeMappingMethodInfo;

++++++++static+MimeExtensionHelper()
++++++++{
++++++++++++Type+mimeMappingType+=+Assembly.GetAssembly(typeof(HttpRuntime)).GetType("System.Web.MimeMapping");
++++++++++++if+(mimeMappingType+==+null)
++++++++++++++++throw+new+SystemException("Couldnt+find+MimeMapping+type");++++++++++++
++++++++++++getMimeMappingMethodInfo+=+mimeMappingType.GetMethod("GetMimeMapping",+BindingFlags.Static+%7C+BindingFlags.NonPublic+%7C+BindingFlags.Public);
++++++++++++if+(getMimeMappingMethodInfo+==+null)
++++++++++++++++throw+new+SystemException("Couldnt+find+GetMimeMapping+method");
++++++++++++if+(getMimeMappingMethodInfo.ReturnType+!=+typeof(string))
++++++++++++++++throw+new+SystemException("GetMimeMapping+method+has+invalid+return+type");
++++++++++++if+(getMimeMappingMethodInfo.GetParameters().Length+!=+1+&&+getMimeMappingMethodInfo.GetParameters()[0].ParameterType+!=+typeof(string))
++++++++++++++++throw+new+SystemException("GetMimeMapping+method+has+invalid+parameters");
++++++++}
++++++++public+static+string+GetMimeType(string+filename)
++++++++{
++++++++++++lock+(locker)
++++++++++++++++return+(string)getMimeMappingMethodInfo.Invoke(mimeMapping,+new+object[]+{+filename+});
++++++++}
++++}|325193|.NET+4.5%2B|BOLD|325194|不需要包装，直接调用公共方法System.Web.MimeMapping.GetMimeMapping。|325195|entityMap|0|LINK|mutability|MUTABLE|url|https://msdn.microsoft.com/en-us/library/system.web.mimemapping.getmimemapping(v=vs.110).aspx^0|0|R|M|0|0|0|0|0|0|0|9|0|E|11|E|11|0|0^^$0|@$1|2|3|4|5|6|7|17|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|18|8|@$D|19|E|1A|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|1B|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1C|8|@]|9|@]|A|$]]|$1|L|3|M|5|N|7|1D|8|@]|9|@]|A|$O|P]]|$1|Q|3|R|5|6|7|1E|8|@]|9|@]|A|$]]|$1|S|3|T|5|N|7|1F|8|@]|9|@]|A|$O|P]]|$1|U|3|V|5|6|7|1G|8|@$D|1H|E|1I|F|W]]|9|@]|A|$]]|$1|X|3|Y|5|6|7|1J|8|@$D|1K|E|1L|F|G]]|9|@$D|1M|E|1N|1|1O]]|A|$]]|$1|Z|3|-4|5|6|7|1P|8|@]|9|@]|A|$]]]|10|$11|$5|12|13|14|A|$15|16]]]]

It depends what you need the MIME type for. In general, for services (web apps, web service, etc.), it's advisable not to use a MIME list which is dependent on the OS settings, or only as fallback if you cannot find MIME information otherwise.

I think that this is also the reason why MS chose to put constant MIME types in their <code>System.Web.MimeMapping</code> class (unfortunately it's internal, for whatever reason).

Edit:

<h3>Wrapper (&lt;= .NET 3.5)</h3>

<pre><code>public static class MimeExtensionHelper
{
 static object locker = new object();
 static object mimeMapping;
 static MethodInfo getMimeMappingMethodInfo;

 static MimeExtensionHelper()
 {
 Type mimeMappingType = Assembly.GetAssembly(typeof(HttpRuntime)).GetType("System.Web.MimeMapping");
 if (mimeMappingType == null)
 throw new SystemException("Couldnt find MimeMapping type");
 ConstructorInfo constructorInfo = mimeMappingType.GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, Type.EmptyTypes, null);
 if (constructorInfo == null)
 throw new SystemException("Couldnt find default constructor for MimeMapping");
 mimeMapping = constructorInfo.Invoke(null);
 if (mimeMapping == null)
 throw new SystemException("Couldnt find MimeMapping");
 getMimeMappingMethodInfo = mimeMappingType.GetMethod("GetMimeMapping", BindingFlags.Static | BindingFlags.NonPublic);
 if (getMimeMappingMethodInfo == null)
 throw new SystemException("Couldnt find GetMimeMapping method");
 if (getMimeMappingMethodInfo.ReturnType != typeof(string))
 throw new SystemException("GetMimeMapping method has invalid return type");
 if (getMimeMappingMethodInfo.GetParameters().Length != 1 &amp;&amp; getMimeMappingMethodInfo.GetParameters()[0].ParameterType != typeof(string))
 throw new SystemException("GetMimeMapping method has invalid parameters");
 }
 public static string GetMimeType(string filename)
 {
 lock (locker)
 return (string)getMimeMappingMethodInfo.Invoke(mimeMapping, new object[] { filename });
 }
}
</code></pre>

<h3>Wrapper (.NET 4.0)</h3>

<pre><code>public static class MimeExtensionHelper
 {
 static object locker = new object();
 static object mimeMapping;
 static MethodInfo getMimeMappingMethodInfo;

 static MimeExtensionHelper()
 {
 Type mimeMappingType = Assembly.GetAssembly(typeof(HttpRuntime)).GetType("System.Web.MimeMapping");
 if (mimeMappingType == null)
 throw new SystemException("Couldnt find MimeMapping type"); 
 getMimeMappingMethodInfo = mimeMappingType.GetMethod("GetMimeMapping", BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public);
 if (getMimeMappingMethodInfo == null)
 throw new SystemException("Couldnt find GetMimeMapping method");
 if (getMimeMappingMethodInfo.ReturnType != typeof(string))
 throw new SystemException("GetMimeMapping method has invalid return type");
 if (getMimeMappingMethodInfo.GetParameters().Length != 1 &amp;&amp; getMimeMappingMethodInfo.GetParameters()[0].ParameterType != typeof(string))
 throw new SystemException("GetMimeMapping method has invalid parameters");
 }
 public static string GetMimeType(string filename)
 {
 lock (locker)
 return (string)getMimeMappingMethodInfo.Invoke(mimeMapping, new object[] { filename });
 }
 }
</code></pre>

.NET 4.5+

No wrapper required, call the public method <a href="https://msdn.microsoft.com/en-us/library/system.web.mimemapping.getmimemapping(v=vs.110).aspx" rel="noreferrer"><code>System.Web.MimeMapping.GetMimeMapping</code></a> directly.

blocks|key|325202|text|我已经在我的实用工具库中组合了所有这些方法，也许除了第三种方法。顺便说一句，no.2+(urlmon.dll)不需要静态文件，它只需要一些字节，无论它们来自哪里。这是我当前的班级|type|unstyled|depth|inlineStyleRanges|entityRanges|data|325203|namespace+Components
{
++++using+System;
++++using+System.Collections.Generic;
++++using+System.IO;
++++using+System.Runtime.InteropServices;
++++using+System.Text;
++++using+System.Xml.Serialization;
++++using+Microsoft.Win32;

++++public+sealed+class+MimeExtensionHelper
++++{
++++++++private+MimeExtensionHelper()+{+}

++++++++///+<summary>Finds+extension+associated+with+specified+mime+type</summary>
++++++++///+<param+name="mimeType">mime+type+you+search+extension+for,+e.g.:+"application/octet-stream"</param>
++++++++///+<returns>most+used+extension,+associated+with+provided+type,+e.g.:+".bin"</returns>
++++++++public+static+string+FindExtension(string+mimeType)
++++++++{
++++++++++++return+ExtensionTypes.GetExtension(mimeType);
++++++++}

++++++++///+<summary>Finds+mime+type+using+provided+extension+and/or+file's+binary+content.</summary>
++++++++///+<param+name="file">Full+file+path</param>
++++++++///+<param+name="verifyFromContent">Should+the+file's+content+be+examined+to+verify+founded+value.</param>
++++++++///+<returns>mime+type+of+file,+e.g.:+"application/octet-stream"</returns>
++++++++public+static+string+FindMime(string+file,bool+verifyFromContent)
++++++++{
++++++++++++string+extension+=+Path.GetExtension(file);
++++++++++++string+mimeType+=+string.Empty;
++++++++++++try
++++++++++++{
++++++++++++++++if+(!String.IsNullOrEmpty(extension))
++++++++++++++++++++mimeType+=+ExtensionTypes.GetMimeType(extension);
++++++++++++++++if+(verifyFromContent
++++++++++++++++++++%7C%7C+(String.IsNullOrEmpty(mimeType)+&&+File.Exists(file)))
++++++++++++++++++++mimeType+=+FindMimeByContent(file,mimeType);
++++++++++++}
++++++++++++catch+{+}
++++++++++++return+(mimeType+??+string.Empty).Trim();//"application/octet-stream"
++++++++}

++++++++///+<summary>Finds+mime+type+for+file+using+it's+binary+data.</summary>
++++++++///+<param+name="file">Full+path+to+file.</param>
++++++++///+<param+name="proposedType">Optional.+Expected+file's+type.</param>
++++++++///+<returns>mime+type,+e.g.:+"application/octet-stream"</returns>
++++++++public+static+string+FindMimeByContent(string+file
++++++++++++,string+proposedType)
++++++++{
++++++++++++FileInfo+fi+=+new+FileInfo(file);
++++++++++++if+(!fi.Exists)
++++++++++++++++throw+new+FileNotFoundException(file);
++++++++++++byte[]+buf+=+new+byte[Math.Min(4096L,fi.Length)];
++++++++++++using+(FileStream+fs+=+File.OpenRead(file))
++++++++++++++++fs.Read(buf,0,buf.Length);
++++++++++++return+FindMimeByData(buf,proposedType);
++++++++}

++++++++///+<summary>Finds+mime+type+for+binary+data.</summary>
++++++++///+<param+name="dataBytes">Binary+data+to+examine.</param>
++++++++///+<param+name="mimeProposed">Optional.+Expected+mime+type.</param>
++++++++///+<returns>mime+type,+e.g.:+"application/octet-stream"</returns>
++++++++public+static+string+FindMimeByData(byte[]+dataBytes,string+mimeProposed)
++++++++{
++++++++++++if+(dataBytes+==+null+%7C%7C+dataBytes.Length+==+0)
++++++++++++++++throw+new+ArgumentNullException("dataBytes");
++++++++++++string+mimeRet+=+String.Empty;
++++++++++++IntPtr+outPtr+=+IntPtr.Zero;
++++++++++++if+(!String.IsNullOrEmpty(mimeProposed))
++++++++++++++++mimeRet+=+mimeProposed;
++++++++++++int+result+=+FindMimeFromData(IntPtr.Zero
++++++++++++++++,null
++++++++++++++++,dataBytes
++++++++++++++++,dataBytes.Length
++++++++++++++++,String.IsNullOrEmpty(mimeProposed)+?+null+:+mimeProposed
++++++++++++++++,0
++++++++++++++++,out+outPtr
++++++++++++++++,0);
++++++++++++if+(result+!=+0)
++++++++++++++++throw+Marshal.GetExceptionForHR(result);
++++++++++++if+(outPtr+!=+null+&&+outPtr+!=+IntPtr.Zero)
++++++++++++{
++++++++++++++++mimeRet+=+Marshal.PtrToStringUni(outPtr);
++++++++++++++++Marshal.FreeCoTaskMem(outPtr);
++++++++++++}
++++++++++++return+mimeRet;
++++++++}

++++++++[DllImport("urlmon.dll"
++++++++++++,CharSet+=+CharSet.Unicode
++++++++++++,ExactSpelling+=+true
++++++++++++,SetLastError+=+true)]
++++++++static+extern+Int32+FindMimeFromData(IntPtr+pBC
++++++++++++,[MarshalAs(UnmanagedType.LPWStr)]+String+pwzUrl
++++++++++++,[MarshalAs(UnmanagedType.LPArray,ArraySubType+=+UnmanagedType.I1,SizeParamIndex+=+3)]+Byte[]+pBuffer
++++++++++++,Int32+cbSize
++++++++++++,[MarshalAs(UnmanagedType.LPWStr)]+String+pwzMimeProposed
++++++++++++,Int32+dwMimeFlags
++++++++++++,out+IntPtr+ppwzMimeOut
++++++++++++,Int32+dwReserved);

++++++++private+static+MimeTypeCollection+_extensionTypes+=+null;
++++++++private+static+MimeTypeCollection+ExtensionTypes
++++++++{
++++++++++++get
++++++++++++{
++++++++++++++++if+(_extensionTypes+==+null)
++++++++++++++++++++_extensionTypes+=+new+MimeTypeCollection();
++++++++++++++++return+_extensionTypes;
++++++++++++}
++++++++}

++++++++[Serializable]
++++++++[XmlRoot(ElementName+=+"mimeTypes")]
++++++++private+class+MimeTypeCollection+:+List<MimeTypeCollection.mimeTypeInfo>
++++++++{
++++++++++++private+SortedList<string,string>+_extensions;
++++++++++++private+SortedList<string,List<string>>+_mimes;

++++++++++++private+void+Init()
++++++++++++{
++++++++++++++++if+(_extensions+==+null+%7C%7C+_mimes+==+null
++++++++++++++++++++%7C%7C+_extensions.Count+==+0+%7C%7C+_mimes.Count+==+0)
++++++++++++++++{
++++++++++++++++++++_extensions+=+new+SortedList<string,string>(StringComparer.OrdinalIgnoreCase);
++++++++++++++++++++_mimes+=+new+SortedList<string,List<string>>(StringComparer.OrdinalIgnoreCase);
++++++++++++++++++++foreach+(var+mime+in+this)
++++++++++++++++++++{
++++++++++++++++++++++++_mimes.Add(mime.MimeType,new+List<string>(mime.Extensions));
++++++++++++++++++++++++foreach+(string+ext+in+mime.Extensions)
++++++++++++++++++++++++++++if+(!_extensions.ContainsKey(ext))
++++++++++++++++++++++++++++++++_extensions.Add(ext,mime.MimeType);
++++++++++++++++++++}
++++++++++++++++}
++++++++++++}

++++++++++++public+String+GetExtension(string+type)
++++++++++++{
++++++++++++++++Init();
++++++++++++++++return+_mimes.ContainsKey(type)+?+_mimes[type][0]+:+string.Empty;
++++++++++++}

++++++++++++public+String+GetMimeType(string+extension)
++++++++++++{
++++++++++++++++Init();
++++++++++++++++return+_extensions.ContainsKey(extension)+?+_extensions[extension]+:+string.Empty;
++++++++++++}

++++++++public+MimeTypeCollection()
++++++++{
++++++++++++this.Add(new+mimeTypeInfo("application/applixware",new+List<string>(new[]+{+".aw"+})));
++++++++++++this.Add(new+mimeTypeInfo("application/atom%2Bxml",new+List<string>(new[]+{+".atom"+})));
++++++++++++//+...+Whole+list+from+apache's+site
++++++++++++this.Add(new+mimeTypeInfo("x-x509-ca-cert",new+List<string>(new[]+{+".cer"+})));
++++++++++++try
++++++++++++{
++++++++++++++++using+(RegistryKey+classesRoot+=+Registry.ClassesRoot)
++++++++++++++++using+(RegistryKey+typeKey+=+classesRoot.OpenSubKey(@"MIME\Database\Content+Type"))
++++++++++++++++{
++++++++++++++++++++string[]+subKeyNames+=+typeKey.GetSubKeyNames();
++++++++++++++++++++string+extension+=+string.Empty;
++++++++++++++++++++foreach+(string+keyname+in+subKeyNames)
++++++++++++++++++++{
++++++++++++++++++++++++string+trimmed+=+(keyname+??+string.Empty).Trim();
++++++++++++++++++++++++if+(string.IsNullOrEmpty(trimmed))
++++++++++++++++++++++++++++continue;
++++++++++++++++++++++++if+(!String.IsNullOrEmpty(GetExtension(trimmed)))
++++++++++++++++++++++++++++continue;
++++++++++++++++++++++++string+subKey+=+"MIME\\Database\\Content+Type\\"+%2B+trimmed;
++++++++++++++++++++++++using+(RegistryKey+curKey+=+classesRoot.OpenSubKey(subKey))
++++++++++++++++++++++++{
++++++++++++++++++++++++++++extension+=+(curKey.GetValue("Extension")+as+string+??+string.Empty).Trim();
++++++++++++++++++++++++++++if+(extension.Length+>+0)
++++++++++++++++++++++++++++++++this.Add(new+mimeTypeInfo(trimmed
++++++++++++++++++++++++++++++++++++,new+List<string>(new[]+{+extension+})));
++++++++++++++++++++++++}
++++++++++++++++++++}
++++++++++++++++}
++++++++++++}
++++++++++++catch+(Exception+ex)
++++++++++++{
++++++++++++++++string+s+=+ex.ToString();
++++++++++++}
++++++++}

++++++++[Serializable]
++++++++public+class+mimeTypeInfo
++++++++{
++++++++++++[XmlAttribute(AttributeName+=+"mimeType")]
++++++++++++public+String+MimeType+{+get;+set;+}

++++++++++++[XmlElement("extension")]
++++++++++++public+List<String>+Extensions+{+get;+set;+}

++++++++++++public+mimeTypeInfo(string+mimeType,List<string>+extensions)
++++++++++++{
++++++++++++++++MimeType+=+mimeType;
++++++++++++++++Extensions+=+extensions;
++++++++++++}

++++++++++++public+mimeTypeInfo()+{+}
++++++++}
++++}
}|code-block|syntax|javascript|325204|}|325205|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I have combined all these approaches in my utility lib, except maybe no.3.
Btw, no.2 (urlmon.dll) doesn't require static file, it simply takes some bytes no matter where they had come from.
Here's my current class

<pre><code>namespace Components
{
 using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Runtime.InteropServices;
 using System.Text;
 using System.Xml.Serialization;
 using Microsoft.Win32;

 public sealed class MimeExtensionHelper
 {
 private MimeExtensionHelper() { }

 /// &lt;summary&gt;Finds extension associated with specified mime type&lt;/summary&gt;
 /// &lt;param name="mimeType"&gt;mime type you search extension for, e.g.: "application/octet-stream"&lt;/param&gt;
 /// &lt;returns&gt;most used extension, associated with provided type, e.g.: ".bin"&lt;/returns&gt;
 public static string FindExtension(string mimeType)
 {
 return ExtensionTypes.GetExtension(mimeType);
 }

 /// &lt;summary&gt;Finds mime type using provided extension and/or file's binary content.&lt;/summary&gt;
 /// &lt;param name="file"&gt;Full file path&lt;/param&gt;
 /// &lt;param name="verifyFromContent"&gt;Should the file's content be examined to verify founded value.&lt;/param&gt;
 /// &lt;returns&gt;mime type of file, e.g.: "application/octet-stream"&lt;/returns&gt;
 public static string FindMime(string file,bool verifyFromContent)
 {
 string extension = Path.GetExtension(file);
 string mimeType = string.Empty;
 try
 {
 if (!String.IsNullOrEmpty(extension))
 mimeType = ExtensionTypes.GetMimeType(extension);
 if (verifyFromContent
 || (String.IsNullOrEmpty(mimeType) &amp;&amp; File.Exists(file)))
 mimeType = FindMimeByContent(file,mimeType);
 }
 catch { }
 return (mimeType ?? string.Empty).Trim();//"application/octet-stream"
 }

 /// &lt;summary&gt;Finds mime type for file using it's binary data.&lt;/summary&gt;
 /// &lt;param name="file"&gt;Full path to file.&lt;/param&gt;
 /// &lt;param name="proposedType"&gt;Optional. Expected file's type.&lt;/param&gt;
 /// &lt;returns&gt;mime type, e.g.: "application/octet-stream"&lt;/returns&gt;
 public static string FindMimeByContent(string file
 ,string proposedType)
 {
 FileInfo fi = new FileInfo(file);
 if (!fi.Exists)
 throw new FileNotFoundException(file);
 byte[] buf = new byte[Math.Min(4096L,fi.Length)];
 using (FileStream fs = File.OpenRead(file))
 fs.Read(buf,0,buf.Length);
 return FindMimeByData(buf,proposedType);
 }

 /// &lt;summary&gt;Finds mime type for binary data.&lt;/summary&gt;
 /// &lt;param name="dataBytes"&gt;Binary data to examine.&lt;/param&gt;
 /// &lt;param name="mimeProposed"&gt;Optional. Expected mime type.&lt;/param&gt;
 /// &lt;returns&gt;mime type, e.g.: "application/octet-stream"&lt;/returns&gt;
 public static string FindMimeByData(byte[] dataBytes,string mimeProposed)
 {
 if (dataBytes == null || dataBytes.Length == 0)
 throw new ArgumentNullException("dataBytes");
 string mimeRet = String.Empty;
 IntPtr outPtr = IntPtr.Zero;
 if (!String.IsNullOrEmpty(mimeProposed))
 mimeRet = mimeProposed;
 int result = FindMimeFromData(IntPtr.Zero
 ,null
 ,dataBytes
 ,dataBytes.Length
 ,String.IsNullOrEmpty(mimeProposed) ? null : mimeProposed
 ,0
 ,out outPtr
 ,0);
 if (result != 0)
 throw Marshal.GetExceptionForHR(result);
 if (outPtr != null &amp;&amp; outPtr != IntPtr.Zero)
 {
 mimeRet = Marshal.PtrToStringUni(outPtr);
 Marshal.FreeCoTaskMem(outPtr);
 }
 return mimeRet;
 }

 [DllImport("urlmon.dll"
 ,CharSet = CharSet.Unicode
 ,ExactSpelling = true
 ,SetLastError = true)]
 static extern Int32 FindMimeFromData(IntPtr pBC
 ,[MarshalAs(UnmanagedType.LPWStr)] String pwzUrl
 ,[MarshalAs(UnmanagedType.LPArray,ArraySubType = UnmanagedType.I1,SizeParamIndex = 3)] Byte[] pBuffer
 ,Int32 cbSize
 ,[MarshalAs(UnmanagedType.LPWStr)] String pwzMimeProposed
 ,Int32 dwMimeFlags
 ,out IntPtr ppwzMimeOut
 ,Int32 dwReserved);

 private static MimeTypeCollection _extensionTypes = null;
 private static MimeTypeCollection ExtensionTypes
 {
 get
 {
 if (_extensionTypes == null)
 _extensionTypes = new MimeTypeCollection();
 return _extensionTypes;
 }
 }

 [Serializable]
 [XmlRoot(ElementName = "mimeTypes")]
 private class MimeTypeCollection : List&lt;MimeTypeCollection.mimeTypeInfo&gt;
 {
 private SortedList&lt;string,string&gt; _extensions;
 private SortedList&lt;string,List&lt;string&gt;&gt; _mimes;

 private void Init()
 {
 if (_extensions == null || _mimes == null
 || _extensions.Count == 0 || _mimes.Count == 0)
 {
 _extensions = new SortedList&lt;string,string&gt;(StringComparer.OrdinalIgnoreCase);
 _mimes = new SortedList&lt;string,List&lt;string&gt;&gt;(StringComparer.OrdinalIgnoreCase);
 foreach (var mime in this)
 {
 _mimes.Add(mime.MimeType,new List&lt;string&gt;(mime.Extensions));
 foreach (string ext in mime.Extensions)
 if (!_extensions.ContainsKey(ext))
 _extensions.Add(ext,mime.MimeType);
 }
 }
 }

 public String GetExtension(string type)
 {
 Init();
 return _mimes.ContainsKey(type) ? _mimes[type][0] : string.Empty;
 }

 public String GetMimeType(string extension)
 {
 Init();
 return _extensions.ContainsKey(extension) ? _extensions[extension] : string.Empty;
 }

 public MimeTypeCollection()
 {
 this.Add(new mimeTypeInfo("application/applixware",new List&lt;string&gt;(new[] { ".aw" })));
 this.Add(new mimeTypeInfo("application/atom+xml",new List&lt;string&gt;(new[] { ".atom" })));
 // ... Whole list from apache's site
 this.Add(new mimeTypeInfo("x-x509-ca-cert",new List&lt;string&gt;(new[] { ".cer" })));
 try
 {
 using (RegistryKey classesRoot = Registry.ClassesRoot)
 using (RegistryKey typeKey = classesRoot.OpenSubKey(@"MIME\Database\Content Type"))
 {
 string[] subKeyNames = typeKey.GetSubKeyNames();
 string extension = string.Empty;
 foreach (string keyname in subKeyNames)
 {
 string trimmed = (keyname ?? string.Empty).Trim();
 if (string.IsNullOrEmpty(trimmed))
 continue;
 if (!String.IsNullOrEmpty(GetExtension(trimmed)))
 continue;
 string subKey = "MIME\\Database\\Content Type\\" + trimmed;
 using (RegistryKey curKey = classesRoot.OpenSubKey(subKey))
 {
 extension = (curKey.GetValue("Extension") as string ?? string.Empty).Trim();
 if (extension.Length &gt; 0)
 this.Add(new mimeTypeInfo(trimmed
 ,new List&lt;string&gt;(new[] { extension })));
 }
 }
 }
 }
 catch (Exception ex)
 {
 string s = ex.ToString();
 }
 }

 [Serializable]
 public class mimeTypeInfo
 {
 [XmlAttribute(AttributeName = "mimeType")]
 public String MimeType { get; set; }

 [XmlElement("extension")]
 public List&lt;String&gt; Extensions { get; set; }

 public mimeTypeInfo(string mimeType,List&lt;string&gt; extensions)
 {
 MimeType = mimeType;
 Extensions = extensions;
 }

 public mimeTypeInfo() { }
 }
 }
}
</code></pre>

}

blocks|key|325223|text|Nisus+-你愿意在某个地方发布你的实用工具的全部源代码吗？这真的会很有帮助。谢谢!|type|unstyled|depth|inlineStyleRanges|entityRanges|data|325224|不要紧……|325225|我编辑了apache定义文件，使其只包含具有已定义扩展名的条目，然后扩展代码，以便在运行时从文本文件加载类型/扩展名。也许不是很优雅，但肯定比为mime类型创建/维护630行源代码要好。|325226|[在应用程序的构造函数中，而不是这个东西中:this.Add(mimeTypeInfo(“MimeTypeCollection+/applixware”，new+List(new[]+{+".aw“})；]|325227|++++++++//+import+mime/extension+definition+list+to+facilitate+maintenance
++++string+dir+=+AppDomain.CurrentDomain.BaseDirectory;
++++using+(TextReader+streamReader+=+new+StreamReader(Path.Combine(dir,+"MimeDefinitions.txt")))
++++{
++++++string+input;
++++++while+((input+=+streamReader.ReadLine())+!=+null)
++++++{
++++++++if+(input.Substring(0,+1)+!=+"#")
++++++++{
++++++++++//+text+line+format+::=+[contenttype]<tab>[space+delimited+list+of+extensions,+without+dot]
++++++++++string+contentType+=+input.Group("0\t1");
++++++++++string+extensionList+=+input.Group("1\t1");
++++++++++string[]+extensions+=+extensionList.Split("+".ToCharArray());
++++++++++List<string>+extensionSet+=+new+List<string>();
++++++++++foreach+(string+term+in+extensions)
++++++++++{
++++++++++++extensionSet.Add("."%2Bterm);
++++++++++}
++++++++++this.Add(new+mimeTypeInfo(contentType,+extensionSet));
++++++++}
++++++}
++++}|code-block|syntax|javascript|325228|我还发现将调用Init()方法，而_extensions和_mime成员不会完全初始化，因此我将其更改为：|325229|if+(_extensions+==+null+%7C%7C+_mimes+==+null+%7C%7C+_mimes.Count+!=+this.Count)|325230|无论如何，我现在知道如何创建一个类来处理我所需要的外部defs和本地注册表。|325231|谢谢!|325232|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Y|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|12|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|14|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

Nisus - would you be willing to post the entire source code for your utility somewhere? that would really be helpful. thanks!

Never mind....

I edited the apache definition file to only contain entries with defined extensions, then extended the code to load in the types/extensions from the text file at run time. Not elegant perhaps but sure beats creating/maintaining 630 lines of source code for the mime types. 

[in the constructor for MimeTypeCollection instead of this stuff:
this.Add(new mimeTypeInfo("application/applixware",new List(new[] { ".aw" })));]

<pre><code> // import mime/extension definition list to facilitate maintenance
 string dir = AppDomain.CurrentDomain.BaseDirectory;
 using (TextReader streamReader = new StreamReader(Path.Combine(dir, "MimeDefinitions.txt")))
 {
 string input;
 while ((input = streamReader.ReadLine()) != null)
 {
 if (input.Substring(0, 1) != "#")
 {
 // text line format ::= [contenttype]&lt;tab&gt;[space delimited list of extensions, without dot]
 string contentType = input.Group("0\t1");
 string extensionList = input.Group("1\t1");
 string[] extensions = extensionList.Split(" ".ToCharArray());
 List&lt;string&gt; extensionSet = new List&lt;string&gt;();
 foreach (string term in extensions)
 {
 extensionSet.Add("."+term);
 }
 this.Add(new mimeTypeInfo(contentType, extensionSet));
 }
 }
 }
</code></pre>

I also found that the Init() method would be called and the _extensions and _mime members would not be completely initialized so I changed it to read:

<pre><code>if (_extensions == null || _mimes == null || _mimes.Count != this.Count)
</code></pre>

Anyway, I now how a class that can handle the external defs and local registry I needed.

Thanks!

blocks|key|326858|text|我还发现将调用Init()方法，而_extensions和_mime成员不会完全初始化，因此我将其更改为read，最好的方法是从MimeTypeCollection中删除构造函数中的GetExtension调用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|326859|++++++++public+MimeTypeCollection()
++++++++{
++++++++++++this.Add(new+mimeTypeInfo("application/applixware",+new+List<string>(new[]+{+".aw"+})));
++++++++++++this.Add(new+mimeTypeInfo("application/atom%2Bxml",+new+List<string>(new[]+{+".atom"+})));
++++++++++++//+...+Whole+list+from+apache's+site
++++++++++++this.Add(new+mimeTypeInfo("x-x509-ca-cert",+new+List<string>(new[]+{+".cer"+})));
++++++++++++try
++++++++++++{
++++++++++++++++using+(RegistryKey+classesRoot+=+Registry.ClassesRoot)
++++++++++++++++using+(RegistryKey+typeKey+=+classesRoot.OpenSubKey(@"MIME\Database\Content+Type"))
++++++++++++++++{
++++++++++++++++++++string[]+subKeyNames+=+typeKey.GetSubKeyNames();
++++++++++++++++++++string+extension+=+string.Empty;
++++++++++++++++++++foreach+(string+keyname+in+subKeyNames)
++++++++++++++++++++{
++++++++++++++++++++++++string+trimmed+=+(keyname+??+string.Empty).Trim();
++++++++++++++++++++++++if+(string.IsNullOrEmpty(trimmed))
++++++++++++++++++++++++++++continue;
++++++++++++++++++++++++if+(this.Exists(mime+=>+mime.MimeType+==+trimmed))
++++++++++++++++++++++++++++continue;
++++++++++++++++++++++++//if+(!String.IsNullOrEmpty(GetExtension(trimmed)))
++++++++++++++++++++++++//++continue;
++++++++++++++++++++++++string+subKey+=+"MIME\\Database\\Content+Type\\"+%2B+trimmed;
++++++++++++++++++++++++using+(RegistryKey+curKey+=+classesRoot.OpenSubKey(subKey))
++++++++++++++++++++++++{
++++++++++++++++++++++++++++extension+=+(curKey.GetValue("Extension")+as+string+??+string.Empty).Trim();
++++++++++++++++++++++++++++if+(extension.Length+>+0)
++++++++++++++++++++++++++++++++this.Add(new+mimeTypeInfo(trimmed
++++++++++++++++++++++++++++++++++++++++,+new+List<string>(new[]+{+extension+})));
++++++++++++++++++++++++}
++++++++++++++++++++}
++++++++++++++++}
++++++++++++}
++++++++++++catch+(Exception+ex)
++++++++++++{
++++++++++++++++string+s+=+ex.ToString();
++++++++++++}
++++++++}|code-block|syntax|javascript|326860|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I also found that the Init() method would be called and the _extensions and _mime members would not be completely initialized so I changed it to read, and the best way is, remove call GetExtension in constructor from MimeTypeCollection:

<pre><code> public MimeTypeCollection()
 {
 this.Add(new mimeTypeInfo("application/applixware", new List&lt;string&gt;(new[] { ".aw" })));
 this.Add(new mimeTypeInfo("application/atom+xml", new List&lt;string&gt;(new[] { ".atom" })));
 // ... Whole list from apache's site
 this.Add(new mimeTypeInfo("x-x509-ca-cert", new List&lt;string&gt;(new[] { ".cer" })));
 try
 {
 using (RegistryKey classesRoot = Registry.ClassesRoot)
 using (RegistryKey typeKey = classesRoot.OpenSubKey(@"MIME\Database\Content Type"))
 {
 string[] subKeyNames = typeKey.GetSubKeyNames();
 string extension = string.Empty;
 foreach (string keyname in subKeyNames)
 {
 string trimmed = (keyname ?? string.Empty).Trim();
 if (string.IsNullOrEmpty(trimmed))
 continue;
 if (this.Exists(mime =&gt; mime.MimeType == trimmed))
 continue;
 //if (!String.IsNullOrEmpty(GetExtension(trimmed)))
 // continue;
 string subKey = "MIME\\Database\\Content Type\\" + trimmed;
 using (RegistryKey curKey = classesRoot.OpenSubKey(subKey))
 {
 extension = (curKey.GetValue("Extension") as string ?? string.Empty).Trim();
 if (extension.Length &gt; 0)
 this.Add(new mimeTypeInfo(trimmed
 , new List&lt;string&gt;(new[] { extension })));
 }
 }
 }
 }
 catch (Exception ex)
 {
 string s = ex.ToString();
 }
 }
</code></pre>

blocks|key|3296113|text|我已经编写了一个程序来获取Apache+mime.types文件并将其转换为以文件扩展名为关键字的C#+Dictionary<string,+string>。它在这里：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3296114|https://github.com/cymen/ApacheMimeTypesToDotNet|3296115|实际的输出是这个文件：|3296116|https://github.com/cymen/ApacheMimeTypesToDotNet/blob/master/ApacheMimeTypes.cs|3296117|希望其他人也能找到有用的东西！|3296118|entityMap|0|LINK|mutability|MUTABLE|url|1^0|1G|Q|0|0|1C|0|0|0|0|27|1|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Y|8|@]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|H|3|I|5|6|7|12|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|13|8|@]|D|@$9|14|A|15|1|16]]|E|$]]|$1|L|3|M|5|6|7|17|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|O|$P|$5|Q|R|S|E|$T|G]]|U|$5|Q|R|S|E|$T|K]]]]

I've written a program to fetch and convert the Apache mime.types file to a C# <code>Dictionary&lt;string, string&gt;</code> keyed by file extension. It's here:

<a href="https://github.com/cymen/ApacheMimeTypesToDotNet">https://github.com/cymen/ApacheMimeTypesToDotNet</a>

The actual output is this file:

<a href="https://github.com/cymen/ApacheMimeTypesToDotNet/blob/master/ApacheMimeTypes.cs">https://github.com/cymen/ApacheMimeTypesToDotNet/blob/master/ApacheMimeTypes.cs</a>

Hopefully someone else finds it useful too!

blocks|key|3082815|text|System.Web.MimeMapping有3个版本-两个版本4.0(其中一个是内部的)，然后是2.0版本，也是内部的。正如所指出的，在用于.NET+4.5框架的System.Web+version+4.0中有一个类的公共版本。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3082816|对于RoadkillWiki，我基本上对它进行了逆向工程，以省去每次反映的麻烦，Wiki的文件处理程序在默认情况下尝试使用IIS/applicationhost.config，然后使用MimeMapping类：|3082817|private+string+GetMimeType(string+fileExtension,+ServerManager+serverManager)
{
++++try
++++{
++++++++string+mimeType+=+"text/plain";

++++++++Microsoft.Web.Administration.Configuration+config+=+serverManager.GetApplicationHostConfiguration();
++++++++ConfigurationSection+staticContentSection+=+config.GetSection("system.webServer/staticContent");
++++++++ConfigurationElementCollection+mimemaps+=+staticContentSection.GetCollection();

++++++++ConfigurationElement+element+=+mimemaps.FirstOrDefault(m+=>+m.Attributes["fileExtension"].Value.ToString()+==+fileExtension);

++++++++if+(element+!=+null)
++++++++++++mimeType+=+element.Attributes["mimeType"].Value.ToString();

++++++++return+mimeType;
++++}
++++catch+(UnauthorizedAccessException)
++++{
++++++++//+Shared+hosting+won't+have+access+to+the+applicationhost.config+file
++++++++return+MimeMapping.GetMimeMapping("."+%2BfileExtension);
++++}
}|code-block|syntax|javascript|3082818|和MimeMapping：|3082819|public+class+MimeMapping
{
++++private+static+Dictionary<string,+string>+ExtensionMap+=+new+Dictionary<string,+string>();

++++static+MimeMapping()
++++{
++++++++ExtensionMap.Add(".323",+"text/h323");
++++++++ExtensionMap.Add(".asx",+"video/x-ms-asf");
++++++++ExtensionMap.Add(".acx",+"application/internet-property-stream");
++++++++ExtensionMap.Add(".ai",+"application/postscript");
++++++++ExtensionMap.Add(".aif",+"audio/x-aiff");
++++++++ExtensionMap.Add(".aiff",+"audio/aiff");
++++++++ExtensionMap.Add(".axs",+"application/olescript");
++++++++ExtensionMap.Add(".aifc",+"audio/aiff");
++++++++ExtensionMap.Add(".asr",+"video/x-ms-asf");
++++++++ExtensionMap.Add(".avi",+"video/x-msvideo");
++++++++ExtensionMap.Add(".asf",+"video/x-ms-asf");
++++++++ExtensionMap.Add(".au",+"audio/basic");
++++++++ExtensionMap.Add(".application",+"application/x-ms-application");
++++++++ExtensionMap.Add(".bin",+"application/octet-stream");
++++++++ExtensionMap.Add(".bas",+"text/plain");
++++++++ExtensionMap.Add(".bcpio",+"application/x-bcpio");
++++++++ExtensionMap.Add(".bmp",+"image/bmp");
++++++++ExtensionMap.Add(".cdf",+"application/x-cdf");
++++++++ExtensionMap.Add(".cat",+"application/vndms-pkiseccat");
++++++++ExtensionMap.Add(".crt",+"application/x-x509-ca-cert");
++++++++ExtensionMap.Add(".c",+"text/plain");
++++++++ExtensionMap.Add(".css",+"text/css");
++++++++ExtensionMap.Add(".cer",+"application/x-x509-ca-cert");
++++++++ExtensionMap.Add(".crl",+"application/pkix-crl");
++++++++ExtensionMap.Add(".cmx",+"image/x-cmx");
++++++++ExtensionMap.Add(".csh",+"application/x-csh");
++++++++ExtensionMap.Add(".cod",+"image/cis-cod");
++++++++ExtensionMap.Add(".cpio",+"application/x-cpio");
++++++++ExtensionMap.Add(".clp",+"application/x-msclip");
++++++++ExtensionMap.Add(".crd",+"application/x-mscardfile");
++++++++ExtensionMap.Add(".deploy",+"application/octet-stream");
++++++++ExtensionMap.Add(".dll",+"application/x-msdownload");
++++++++ExtensionMap.Add(".dot",+"application/msword");
++++++++ExtensionMap.Add(".doc",+"application/msword");
++++++++ExtensionMap.Add(".dvi",+"application/x-dvi");
++++++++ExtensionMap.Add(".dir",+"application/x-director");
++++++++ExtensionMap.Add(".dxr",+"application/x-director");
++++++++ExtensionMap.Add(".der",+"application/x-x509-ca-cert");
++++++++ExtensionMap.Add(".dib",+"image/bmp");
++++++++ExtensionMap.Add(".dcr",+"application/x-director");
++++++++ExtensionMap.Add(".disco",+"text/xml");
++++++++ExtensionMap.Add(".exe",+"application/octet-stream");
++++++++ExtensionMap.Add(".etx",+"text/x-setext");
++++++++ExtensionMap.Add(".evy",+"application/envoy");
++++++++ExtensionMap.Add(".eml",+"message/rfc822");
++++++++ExtensionMap.Add(".eps",+"application/postscript");
++++++++ExtensionMap.Add(".flr",+"x-world/x-vrml");
++++++++ExtensionMap.Add(".fif",+"application/fractals");
++++++++ExtensionMap.Add(".gtar",+"application/x-gtar");
++++++++ExtensionMap.Add(".gif",+"image/gif");
++++++++ExtensionMap.Add(".gz",+"application/x-gzip");
++++++++ExtensionMap.Add(".hta",+"application/hta");
++++++++ExtensionMap.Add(".htc",+"text/x-component");
++++++++ExtensionMap.Add(".htt",+"text/webviewhtml");
++++++++ExtensionMap.Add(".h",+"text/plain");
++++++++ExtensionMap.Add(".hdf",+"application/x-hdf");
++++++++ExtensionMap.Add(".hlp",+"application/winhlp");
++++++++ExtensionMap.Add(".html",+"text/html");
++++++++ExtensionMap.Add(".htm",+"text/html");
++++++++ExtensionMap.Add(".hqx",+"application/mac-binhex40");
++++++++ExtensionMap.Add(".isp",+"application/x-internet-signup");
++++++++ExtensionMap.Add(".iii",+"application/x-iphone");
++++++++ExtensionMap.Add(".ief",+"image/ief");
++++++++ExtensionMap.Add(".ivf",+"video/x-ivf");
++++++++ExtensionMap.Add(".ins",+"application/x-internet-signup");
++++++++ExtensionMap.Add(".ico",+"image/x-icon");
++++++++ExtensionMap.Add(".jpg",+"image/jpeg");
++++++++ExtensionMap.Add(".jfif",+"image/pjpeg");
++++++++ExtensionMap.Add(".jpe",+"image/jpeg");
++++++++ExtensionMap.Add(".jpeg",+"image/jpeg");
++++++++ExtensionMap.Add(".js",+"application/x-javascript");
++++++++ExtensionMap.Add(".lsx",+"video/x-la-asf");
++++++++ExtensionMap.Add(".latex",+"application/x-latex");
++++++++ExtensionMap.Add(".lsf",+"video/x-la-asf");
++++++++ExtensionMap.Add(".manifest",+"application/x-ms-manifest");
++++++++ExtensionMap.Add(".mhtml",+"message/rfc822");
++++++++ExtensionMap.Add(".mny",+"application/x-msmoney");
++++++++ExtensionMap.Add(".mht",+"message/rfc822");
++++++++ExtensionMap.Add(".mid",+"audio/mid");
++++++++ExtensionMap.Add(".mpv2",+"video/mpeg");
++++++++ExtensionMap.Add(".man",+"application/x-troff-man");
++++++++ExtensionMap.Add(".mvb",+"application/x-msmediaview");
++++++++ExtensionMap.Add(".mpeg",+"video/mpeg");
++++++++ExtensionMap.Add(".m3u",+"audio/x-mpegurl");
++++++++ExtensionMap.Add(".mdb",+"application/x-msaccess");
++++++++ExtensionMap.Add(".mpp",+"application/vnd.ms-project");
++++++++ExtensionMap.Add(".m1v",+"video/mpeg");
++++++++ExtensionMap.Add(".mpa",+"video/mpeg");
++++++++ExtensionMap.Add(".me",+"application/x-troff-me");
++++++++ExtensionMap.Add(".m13",+"application/x-msmediaview");
++++++++ExtensionMap.Add(".movie",+"video/x-sgi-movie");
++++++++ExtensionMap.Add(".m14",+"application/x-msmediaview");
++++++++ExtensionMap.Add(".mpe",+"video/mpeg");
++++++++ExtensionMap.Add(".mp2",+"video/mpeg");
++++++++ExtensionMap.Add(".mov",+"video/quicktime");
++++++++ExtensionMap.Add(".mp3",+"audio/mpeg");
++++++++ExtensionMap.Add(".mpg",+"video/mpeg");
++++++++ExtensionMap.Add(".ms",+"application/x-troff-ms");
++++++++ExtensionMap.Add(".nc",+"application/x-netcdf");
++++++++ExtensionMap.Add(".nws",+"message/rfc822");
++++++++ExtensionMap.Add(".oda",+"application/oda");
++++++++ExtensionMap.Add(".ods",+"application/oleobject");
++++++++ExtensionMap.Add(".pmc",+"application/x-perfmon");
++++++++ExtensionMap.Add(".p7r",+"application/x-pkcs7-certreqresp");
++++++++ExtensionMap.Add(".p7b",+"application/x-pkcs7-certificates");
++++++++ExtensionMap.Add(".p7s",+"application/pkcs7-signature");
++++++++ExtensionMap.Add(".pmw",+"application/x-perfmon");
++++++++ExtensionMap.Add(".ps",+"application/postscript");
++++++++ExtensionMap.Add(".p7c",+"application/pkcs7-mime");
++++++++ExtensionMap.Add(".pbm",+"image/x-portable-bitmap");
++++++++ExtensionMap.Add(".ppm",+"image/x-portable-pixmap");
++++++++ExtensionMap.Add(".pub",+"application/x-mspublisher");
++++++++ExtensionMap.Add(".pnm",+"image/x-portable-anymap");
++++++++ExtensionMap.Add(".pml",+"application/x-perfmon");
++++++++ExtensionMap.Add(".p10",+"application/pkcs10");
++++++++ExtensionMap.Add(".pfx",+"application/x-pkcs12");
++++++++ExtensionMap.Add(".p12",+"application/x-pkcs12");
++++++++ExtensionMap.Add(".pdf",+"application/pdf");
++++++++ExtensionMap.Add(".pps",+"application/vnd.ms-powerpoint");
++++++++ExtensionMap.Add(".p7m",+"application/pkcs7-mime");
++++++++ExtensionMap.Add(".pko",+"application/vndms-pkipko");
++++++++ExtensionMap.Add(".ppt",+"application/vnd.ms-powerpoint");
++++++++ExtensionMap.Add(".pmr",+"application/x-perfmon");
++++++++ExtensionMap.Add(".pma",+"application/x-perfmon");
++++++++ExtensionMap.Add(".pot",+"application/vnd.ms-powerpoint");
++++++++ExtensionMap.Add(".prf",+"application/pics-rules");
++++++++ExtensionMap.Add(".pgm",+"image/x-portable-graymap");
++++++++ExtensionMap.Add(".qt",+"video/quicktime");
++++++++ExtensionMap.Add(".ra",+"audio/x-pn-realaudio");
++++++++ExtensionMap.Add(".rgb",+"image/x-rgb");
++++++++ExtensionMap.Add(".ram",+"audio/x-pn-realaudio");
++++++++ExtensionMap.Add(".rmi",+"audio/mid");
++++++++ExtensionMap.Add(".ras",+"image/x-cmu-raster");
++++++++ExtensionMap.Add(".roff",+"application/x-troff");
++++++++ExtensionMap.Add(".rtf",+"application/rtf");
++++++++ExtensionMap.Add(".rtx",+"text/richtext");
++++++++ExtensionMap.Add(".sv4crc",+"application/x-sv4crc");
++++++++ExtensionMap.Add(".spc",+"application/x-pkcs7-certificates");
++++++++ExtensionMap.Add(".setreg",+"application/set-registration-initiation");
++++++++ExtensionMap.Add(".snd",+"audio/basic");
++++++++ExtensionMap.Add(".stl",+"application/vndms-pkistl");
++++++++ExtensionMap.Add(".setpay",+"application/set-payment-initiation");
++++++++ExtensionMap.Add(".stm",+"text/html");
++++++++ExtensionMap.Add(".shar",+"application/x-shar");
++++++++ExtensionMap.Add(".sh",+"application/x-sh");
++++++++ExtensionMap.Add(".sit",+"application/x-stuffit");
++++++++ExtensionMap.Add(".spl",+"application/futuresplash");
++++++++ExtensionMap.Add(".sct",+"text/scriptlet");
++++++++ExtensionMap.Add(".scd",+"application/x-msschedule");
++++++++ExtensionMap.Add(".sst",+"application/vndms-pkicertstore");
++++++++ExtensionMap.Add(".src",+"application/x-wais-source");
++++++++ExtensionMap.Add(".sv4cpio",+"application/x-sv4cpio");
++++++++ExtensionMap.Add(".tex",+"application/x-tex");
++++++++ExtensionMap.Add(".tgz",+"application/x-compressed");
++++++++ExtensionMap.Add(".t",+"application/x-troff");
++++++++ExtensionMap.Add(".tar",+"application/x-tar");
++++++++ExtensionMap.Add(".tr",+"application/x-troff");
++++++++ExtensionMap.Add(".tif",+"image/tiff");
++++++++ExtensionMap.Add(".txt",+"text/plain");
++++++++ExtensionMap.Add(".texinfo",+"application/x-texinfo");
++++++++ExtensionMap.Add(".trm",+"application/x-msterminal");
++++++++ExtensionMap.Add(".tiff",+"image/tiff");
++++++++ExtensionMap.Add(".tcl",+"application/x-tcl");
++++++++ExtensionMap.Add(".texi",+"application/x-texinfo");
++++++++ExtensionMap.Add(".tsv",+"text/tab-separated-values");
++++++++ExtensionMap.Add(".ustar",+"application/x-ustar");
++++++++ExtensionMap.Add(".uls",+"text/iuls");
++++++++ExtensionMap.Add(".vcf",+"text/x-vcard");
++++++++ExtensionMap.Add(".wps",+"application/vnd.ms-works");
++++++++ExtensionMap.Add(".wav",+"audio/wav");
++++++++ExtensionMap.Add(".wrz",+"x-world/x-vrml");
++++++++ExtensionMap.Add(".wri",+"application/x-mswrite");
++++++++ExtensionMap.Add(".wks",+"application/vnd.ms-works");
++++++++ExtensionMap.Add(".wmf",+"application/x-msmetafile");
++++++++ExtensionMap.Add(".wcm",+"application/vnd.ms-works");
++++++++ExtensionMap.Add(".wrl",+"x-world/x-vrml");
++++++++ExtensionMap.Add(".wdb",+"application/vnd.ms-works");
++++++++ExtensionMap.Add(".wsdl",+"text/xml");
++++++++ExtensionMap.Add(".xml",+"text/xml");
++++++++ExtensionMap.Add(".xlm",+"application/vnd.ms-excel");
++++++++ExtensionMap.Add(".xaf",+"x-world/x-vrml");
++++++++ExtensionMap.Add(".xla",+"application/vnd.ms-excel");
++++++++ExtensionMap.Add(".xls",+"application/vnd.ms-excel");
++++++++ExtensionMap.Add(".xof",+"x-world/x-vrml");
++++++++ExtensionMap.Add(".xlt",+"application/vnd.ms-excel");
++++++++ExtensionMap.Add(".xlc",+"application/vnd.ms-excel");
++++++++ExtensionMap.Add(".xsl",+"text/xml");
++++++++ExtensionMap.Add(".xbm",+"image/x-xbitmap");
++++++++ExtensionMap.Add(".xlw",+"application/vnd.ms-excel");
++++++++ExtensionMap.Add(".xpm",+"image/x-xpixmap");
++++++++ExtensionMap.Add(".xwd",+"image/x-xwindowdump");
++++++++ExtensionMap.Add(".xsd",+"text/xml");
++++++++ExtensionMap.Add(".z",+"application/x-compress");
++++++++ExtensionMap.Add(".zip",+"application/x-zip-compressed");
++++++++ExtensionMap.Add(".*",+"application/octet-stream");
++++}

++++public+static+string+GetMimeMapping(string+fileExtension)
++++{
++++++++if+(ExtensionMap.ContainsKey(fileExtension))
++++++++++++return+ExtensionMap[fileExtension];
++++++++else
++++++++++++return+ExtensionMap[".*"];
++++}
}|3082820|entityMap^0|0|M|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|X|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|R|$]]

The <code>System.Web.MimeMapping</code> has 3 versions - two version 4.0s (where one of these is internal), and then a version 2.0 which is also internal. As pointed out, there is a public version of the class in System.Web version 4.0 for the .NET 4.5 framework.

For RoadkillWiki I've basically reverse engineered it to save the bother of reflecting each time, the Wiki's file handler tries to the use IIS/applicationhost.config by default, and then falls through to the MimeMapping class:

<pre><code>private string GetMimeType(string fileExtension, ServerManager serverManager)
{
 try
 {
 string mimeType = "text/plain";

 Microsoft.Web.Administration.Configuration config = serverManager.GetApplicationHostConfiguration();
 ConfigurationSection staticContentSection = config.GetSection("system.webServer/staticContent");
 ConfigurationElementCollection mimemaps = staticContentSection.GetCollection();

 ConfigurationElement element = mimemaps.FirstOrDefault(m =&gt; m.Attributes["fileExtension"].Value.ToString() == fileExtension);

 if (element != null)
 mimeType = element.Attributes["mimeType"].Value.ToString();

 return mimeType;
 }
 catch (UnauthorizedAccessException)
 {
 // Shared hosting won't have access to the applicationhost.config file
 return MimeMapping.GetMimeMapping("." +fileExtension);
 }
}
</code></pre>

And MimeMapping:

<pre><code>public class MimeMapping
{
 private static Dictionary&lt;string, string&gt; ExtensionMap = new Dictionary&lt;string, string&gt;();

 static MimeMapping()
 {
 ExtensionMap.Add(".323", "text/h323");
 ExtensionMap.Add(".asx", "video/x-ms-asf");
 ExtensionMap.Add(".acx", "application/internet-property-stream");
 ExtensionMap.Add(".ai", "application/postscript");
 ExtensionMap.Add(".aif", "audio/x-aiff");
 ExtensionMap.Add(".aiff", "audio/aiff");
 ExtensionMap.Add(".axs", "application/olescript");
 ExtensionMap.Add(".aifc", "audio/aiff");
 ExtensionMap.Add(".asr", "video/x-ms-asf");
 ExtensionMap.Add(".avi", "video/x-msvideo");
 ExtensionMap.Add(".asf", "video/x-ms-asf");
 ExtensionMap.Add(".au", "audio/basic");
 ExtensionMap.Add(".application", "application/x-ms-application");
 ExtensionMap.Add(".bin", "application/octet-stream");
 ExtensionMap.Add(".bas", "text/plain");
 ExtensionMap.Add(".bcpio", "application/x-bcpio");
 ExtensionMap.Add(".bmp", "image/bmp");
 ExtensionMap.Add(".cdf", "application/x-cdf");
 ExtensionMap.Add(".cat", "application/vndms-pkiseccat");
 ExtensionMap.Add(".crt", "application/x-x509-ca-cert");
 ExtensionMap.Add(".c", "text/plain");
 ExtensionMap.Add(".css", "text/css");
 ExtensionMap.Add(".cer", "application/x-x509-ca-cert");
 ExtensionMap.Add(".crl", "application/pkix-crl");
 ExtensionMap.Add(".cmx", "image/x-cmx");
 ExtensionMap.Add(".csh", "application/x-csh");
 ExtensionMap.Add(".cod", "image/cis-cod");
 ExtensionMap.Add(".cpio", "application/x-cpio");
 ExtensionMap.Add(".clp", "application/x-msclip");
 ExtensionMap.Add(".crd", "application/x-mscardfile");
 ExtensionMap.Add(".deploy", "application/octet-stream");
 ExtensionMap.Add(".dll", "application/x-msdownload");
 ExtensionMap.Add(".dot", "application/msword");
 ExtensionMap.Add(".doc", "application/msword");
 ExtensionMap.Add(".dvi", "application/x-dvi");
 ExtensionMap.Add(".dir", "application/x-director");
 ExtensionMap.Add(".dxr", "application/x-director");
 ExtensionMap.Add(".der", "application/x-x509-ca-cert");
 ExtensionMap.Add(".dib", "image/bmp");
 ExtensionMap.Add(".dcr", "application/x-director");
 ExtensionMap.Add(".disco", "text/xml");
 ExtensionMap.Add(".exe", "application/octet-stream");
 ExtensionMap.Add(".etx", "text/x-setext");
 ExtensionMap.Add(".evy", "application/envoy");
 ExtensionMap.Add(".eml", "message/rfc822");
 ExtensionMap.Add(".eps", "application/postscript");
 ExtensionMap.Add(".flr", "x-world/x-vrml");
 ExtensionMap.Add(".fif", "application/fractals");
 ExtensionMap.Add(".gtar", "application/x-gtar");
 ExtensionMap.Add(".gif", "image/gif");
 ExtensionMap.Add(".gz", "application/x-gzip");
 ExtensionMap.Add(".hta", "application/hta");
 ExtensionMap.Add(".htc", "text/x-component");
 ExtensionMap.Add(".htt", "text/webviewhtml");
 ExtensionMap.Add(".h", "text/plain");
 ExtensionMap.Add(".hdf", "application/x-hdf");
 ExtensionMap.Add(".hlp", "application/winhlp");
 ExtensionMap.Add(".html", "text/html");
 ExtensionMap.Add(".htm", "text/html");
 ExtensionMap.Add(".hqx", "application/mac-binhex40");
 ExtensionMap.Add(".isp", "application/x-internet-signup");
 ExtensionMap.Add(".iii", "application/x-iphone");
 ExtensionMap.Add(".ief", "image/ief");
 ExtensionMap.Add(".ivf", "video/x-ivf");
 ExtensionMap.Add(".ins", "application/x-internet-signup");
 ExtensionMap.Add(".ico", "image/x-icon");
 ExtensionMap.Add(".jpg", "image/jpeg");
 ExtensionMap.Add(".jfif", "image/pjpeg");
 ExtensionMap.Add(".jpe", "image/jpeg");
 ExtensionMap.Add(".jpeg", "image/jpeg");
 ExtensionMap.Add(".js", "application/x-javascript");
 ExtensionMap.Add(".lsx", "video/x-la-asf");
 ExtensionMap.Add(".latex", "application/x-latex");
 ExtensionMap.Add(".lsf", "video/x-la-asf");
 ExtensionMap.Add(".manifest", "application/x-ms-manifest");
 ExtensionMap.Add(".mhtml", "message/rfc822");
 ExtensionMap.Add(".mny", "application/x-msmoney");
 ExtensionMap.Add(".mht", "message/rfc822");
 ExtensionMap.Add(".mid", "audio/mid");
 ExtensionMap.Add(".mpv2", "video/mpeg");
 ExtensionMap.Add(".man", "application/x-troff-man");
 ExtensionMap.Add(".mvb", "application/x-msmediaview");
 ExtensionMap.Add(".mpeg", "video/mpeg");
 ExtensionMap.Add(".m3u", "audio/x-mpegurl");
 ExtensionMap.Add(".mdb", "application/x-msaccess");
 ExtensionMap.Add(".mpp", "application/vnd.ms-project");
 ExtensionMap.Add(".m1v", "video/mpeg");
 ExtensionMap.Add(".mpa", "video/mpeg");
 ExtensionMap.Add(".me", "application/x-troff-me");
 ExtensionMap.Add(".m13", "application/x-msmediaview");
 ExtensionMap.Add(".movie", "video/x-sgi-movie");
 ExtensionMap.Add(".m14", "application/x-msmediaview");
 ExtensionMap.Add(".mpe", "video/mpeg");
 ExtensionMap.Add(".mp2", "video/mpeg");
 ExtensionMap.Add(".mov", "video/quicktime");
 ExtensionMap.Add(".mp3", "audio/mpeg");
 ExtensionMap.Add(".mpg", "video/mpeg");
 ExtensionMap.Add(".ms", "application/x-troff-ms");
 ExtensionMap.Add(".nc", "application/x-netcdf");
 ExtensionMap.Add(".nws", "message/rfc822");
 ExtensionMap.Add(".oda", "application/oda");
 ExtensionMap.Add(".ods", "application/oleobject");
 ExtensionMap.Add(".pmc", "application/x-perfmon");
 ExtensionMap.Add(".p7r", "application/x-pkcs7-certreqresp");
 ExtensionMap.Add(".p7b", "application/x-pkcs7-certificates");
 ExtensionMap.Add(".p7s", "application/pkcs7-signature");
 ExtensionMap.Add(".pmw", "application/x-perfmon");
 ExtensionMap.Add(".ps", "application/postscript");
 ExtensionMap.Add(".p7c", "application/pkcs7-mime");
 ExtensionMap.Add(".pbm", "image/x-portable-bitmap");
 ExtensionMap.Add(".ppm", "image/x-portable-pixmap");
 ExtensionMap.Add(".pub", "application/x-mspublisher");
 ExtensionMap.Add(".pnm", "image/x-portable-anymap");
 ExtensionMap.Add(".pml", "application/x-perfmon");
 ExtensionMap.Add(".p10", "application/pkcs10");
 ExtensionMap.Add(".pfx", "application/x-pkcs12");
 ExtensionMap.Add(".p12", "application/x-pkcs12");
 ExtensionMap.Add(".pdf", "application/pdf");
 ExtensionMap.Add(".pps", "application/vnd.ms-powerpoint");
 ExtensionMap.Add(".p7m", "application/pkcs7-mime");
 ExtensionMap.Add(".pko", "application/vndms-pkipko");
 ExtensionMap.Add(".ppt", "application/vnd.ms-powerpoint");
 ExtensionMap.Add(".pmr", "application/x-perfmon");
 ExtensionMap.Add(".pma", "application/x-perfmon");
 ExtensionMap.Add(".pot", "application/vnd.ms-powerpoint");
 ExtensionMap.Add(".prf", "application/pics-rules");
 ExtensionMap.Add(".pgm", "image/x-portable-graymap");
 ExtensionMap.Add(".qt", "video/quicktime");
 ExtensionMap.Add(".ra", "audio/x-pn-realaudio");
 ExtensionMap.Add(".rgb", "image/x-rgb");
 ExtensionMap.Add(".ram", "audio/x-pn-realaudio");
 ExtensionMap.Add(".rmi", "audio/mid");
 ExtensionMap.Add(".ras", "image/x-cmu-raster");
 ExtensionMap.Add(".roff", "application/x-troff");
 ExtensionMap.Add(".rtf", "application/rtf");
 ExtensionMap.Add(".rtx", "text/richtext");
 ExtensionMap.Add(".sv4crc", "application/x-sv4crc");
 ExtensionMap.Add(".spc", "application/x-pkcs7-certificates");
 ExtensionMap.Add(".setreg", "application/set-registration-initiation");
 ExtensionMap.Add(".snd", "audio/basic");
 ExtensionMap.Add(".stl", "application/vndms-pkistl");
 ExtensionMap.Add(".setpay", "application/set-payment-initiation");
 ExtensionMap.Add(".stm", "text/html");
 ExtensionMap.Add(".shar", "application/x-shar");
 ExtensionMap.Add(".sh", "application/x-sh");
 ExtensionMap.Add(".sit", "application/x-stuffit");
 ExtensionMap.Add(".spl", "application/futuresplash");
 ExtensionMap.Add(".sct", "text/scriptlet");
 ExtensionMap.Add(".scd", "application/x-msschedule");
 ExtensionMap.Add(".sst", "application/vndms-pkicertstore");
 ExtensionMap.Add(".src", "application/x-wais-source");
 ExtensionMap.Add(".sv4cpio", "application/x-sv4cpio");
 ExtensionMap.Add(".tex", "application/x-tex");
 ExtensionMap.Add(".tgz", "application/x-compressed");
 ExtensionMap.Add(".t", "application/x-troff");
 ExtensionMap.Add(".tar", "application/x-tar");
 ExtensionMap.Add(".tr", "application/x-troff");
 ExtensionMap.Add(".tif", "image/tiff");
 ExtensionMap.Add(".txt", "text/plain");
 ExtensionMap.Add(".texinfo", "application/x-texinfo");
 ExtensionMap.Add(".trm", "application/x-msterminal");
 ExtensionMap.Add(".tiff", "image/tiff");
 ExtensionMap.Add(".tcl", "application/x-tcl");
 ExtensionMap.Add(".texi", "application/x-texinfo");
 ExtensionMap.Add(".tsv", "text/tab-separated-values");
 ExtensionMap.Add(".ustar", "application/x-ustar");
 ExtensionMap.Add(".uls", "text/iuls");
 ExtensionMap.Add(".vcf", "text/x-vcard");
 ExtensionMap.Add(".wps", "application/vnd.ms-works");
 ExtensionMap.Add(".wav", "audio/wav");
 ExtensionMap.Add(".wrz", "x-world/x-vrml");
 ExtensionMap.Add(".wri", "application/x-mswrite");
 ExtensionMap.Add(".wks", "application/vnd.ms-works");
 ExtensionMap.Add(".wmf", "application/x-msmetafile");
 ExtensionMap.Add(".wcm", "application/vnd.ms-works");
 ExtensionMap.Add(".wrl", "x-world/x-vrml");
 ExtensionMap.Add(".wdb", "application/vnd.ms-works");
 ExtensionMap.Add(".wsdl", "text/xml");
 ExtensionMap.Add(".xml", "text/xml");
 ExtensionMap.Add(".xlm", "application/vnd.ms-excel");
 ExtensionMap.Add(".xaf", "x-world/x-vrml");
 ExtensionMap.Add(".xla", "application/vnd.ms-excel");
 ExtensionMap.Add(".xls", "application/vnd.ms-excel");
 ExtensionMap.Add(".xof", "x-world/x-vrml");
 ExtensionMap.Add(".xlt", "application/vnd.ms-excel");
 ExtensionMap.Add(".xlc", "application/vnd.ms-excel");
 ExtensionMap.Add(".xsl", "text/xml");
 ExtensionMap.Add(".xbm", "image/x-xbitmap");
 ExtensionMap.Add(".xlw", "application/vnd.ms-excel");
 ExtensionMap.Add(".xpm", "image/x-xpixmap");
 ExtensionMap.Add(".xwd", "image/x-xwindowdump");
 ExtensionMap.Add(".xsd", "text/xml");
 ExtensionMap.Add(".z", "application/x-compress");
 ExtensionMap.Add(".zip", "application/x-zip-compressed");
 ExtensionMap.Add(".*", "application/octet-stream");
 }

 public static string GetMimeMapping(string fileExtension)
 {
 if (ExtensionMap.ContainsKey(fileExtension))
 return ExtensionMap[fileExtension];
 else
 return ExtensionMap[".*"];
 }
}
</code></pre>

blocks|key|330317|text|我只想提醒您，在未根据文件的实际内容对其进行验证的情况下检索文件的Mime+/+content类型，因为这可能会给您的系统和用户带来严重的安全风险。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|330318|尽管这样的事情有一些有效的用例，但攻击者可能会攻击您的系统或将其用作将恶意文件传播给其他用户的机制，方法是将可执行文件或脚本伪装成其他非可疑文件类型。|330319|建议您在继续处理上传的文件(或使其可供下载)之前，认真考虑对上传的文件执行沙箱和深度内容检查。|330320|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

I would just like to caution you against retrieving the Mime / content type of a file without validating it against the actual content of the file, as it could pose a serious security risk to your system and users. 

Although there are valid use cases for something like this, attackers can potentially attack your system or use it as a mechanism to propagate malicious files to other users, by disguising executables or scripts as other, non-suspect file types.

It is advisable that you seriously consider sandboxing and performing deep content inspection on uploaded files before continuing to process it (or making it available for download).

I want to get a MIME Content-Type from a given extension (preferably without accessing the physical file). I have seen some questions about this and the methods described to perform this can be resumed in:

<ol>
<li>Use <a href="https://stackoverflow.com/questions/1029740/get-a-mime-from-an-extention/1029796#1029796">registry information</a>.</li>
<li>Use <a href="https://stackoverflow.com/questions/58510/in-c-how-can-you-find-the-mime-type-of-a-file-based-on-the-file-signature-not-th/58570#58570">urlmon.dll's FindMimeFromData</a>.</li>
<li>Use <a href="https://stackoverflow.com/questions/174888/asp-net-iis6-how-to-search-the-servers-mime-map/174988#174988">IIS information</a>.</li>
<li>Roll your own MIME mapping function. Based on <a href="http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types" rel="noreferrer">this table</a>, for example.</li>
</ol>

I've been using no.1 for some time but I realized that the information provided by the registry is not consistent and depends on the software installed on the machine. Some extensions, like .zip don't use to have a Content-Type specified.

Solution no.2 forces me to have the file on disk in order to read the first bytes, which is something slow but may get good results.

The third method is based on Directory Services and all that stuff, which is something I don't like much because I have to add COM references and I'm not sure it's consistent between IIS6 and IIS7. Also, I don't know the performance of this method.

Finally, I didn't want to use my own table but at the end seems the best option if I want a decent performance and consistency of the results between platforms (even Mono).

Do you think there's a better option than using my own table or one of other described methods are better? What's your experience?

File extensions and MIME Types in .NET

我想从给定的扩展名中获取一个MIME Content-Type (最好不访问物理文件)。我已经看到了一些关于这方面的问题，可以在下面的文章中继续介绍执行此操作的方法：.Use .Use .Roll 使用你自己的MIME映射函数。例如，基于。我使用no.1已经有一段时间了，但我意识到注册表提供的信息并不一致，并且取决于机...

问.NET中的文件扩展名和MIME类型
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