Check if an enum has a field that equals a string

public enum FileExtentions {
    mp3,
    mpeg
}

FileExtensions.Any(e=>e.ToString().Equals(file.Extension));

Enum.GetNames(typeof(FileExtensions)).Any(f=>f.Equals("."+file.Extension))

public static bool HasExtension(this FileInfo file)
{
    var ext = file.Extension.StartsWith(".") ? file.Extension.Substring(1)
                                             : file.Extension;

    return Enum.GetNames(typeof(FileExtensions))
               .Any(f => f.Equals(ext));
}

bool hasExtension = file.HasExtension();

string extension = Enum.GetName(typeof(FileExtensions), FileExtensions.mp3);

if (extension == file.Extension)
  // do something here

bool result = Enum.GetNames(typeof(FileExtensions)).Contains("mp3");

Enum.IsDefined(typeof(FileExtension), file.Extension.Substring(1).ToLower())

IEnumerable<string> GetNames(this Type t) {
   if (!t.IsEnum) throw new ArgumentException();

   return Enum.GetNames(t);
}

typeof(FileExtensions).GetNames().Any(e=>e.ToString().Equals(file.Extension));

bool IsDefined(this Type t, string name) {
   if (!t.IsEnum) throw new ArgumentException();

   return Enum.IsDefined(t, name);
}

typeof(FileExtension).IsDefined(file.Extension);