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,或者仅在无法以其他方式找到MIME信息时才将其作为后备.
我认为这也是MS Select 在System.Web.MimeMapping
类中放入常量MIME类型的原因(不幸的是,不管出于什么原因,它是内部的).
编辑:
Wrapper (<= .NET 3.5)
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 && 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 });
}
}
包装器(.NET 4.0)
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 && 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 });
}
}
.NET 4.5+
不需要包装器,直接调用公共方法System.Web.MimeMapping.GetMimeMapping
.