***的解决方案，我所知道的是查询注册表。你可以在这里找到示例代码。
http://cyotek.com/blog/mime-types-and-file-extensions

 公共静态字符串GetDefaultExtension（字符串mime类型）
 {
字符串结果; 
的RegistryKey关键; 
对象的值; 

键= Registry.ClassesRoot.OpenSubKey（@MIME\Database\Content Type\+ mime类型，FALSE）; 
 =键的值！= NULL？ key.GetValue（扩展，NULL）：空; 
结果=值！= NULL？ value.ToString（）的String.Empty; 

返回结果; 
} 
 

How can I get file extension by content type ?

Example I know that file is "text/css" so extension will be ".css".

private static string GetExtension(string contentType)
{
    string ext = ".";

    { DETERMINATION CODE IN HERE }

    return ext;
}

The "Best" solution that I know of is to query the registry. You can find example code here. http://cyotek.com/blog/mime-types-and-file-extensions

 public static string GetDefaultExtension(string mimeType)
    {
      string result;
      RegistryKey key;
      object value;

      key = Registry.ClassesRoot.OpenSubKey(@"MIME\Database\Content Type\" + mimeType, false);
      value = key != null ? key.GetValue("Extension", null) : null;
      result = value != null ? value.ToString() : string.Empty;

      return result;
    }