class Program    {        static void Main(string[] args)        {            string file = Assembly.GetEntryAssembly().Location;            FileAttributes attributes = File.GetAttributes(file);            Console.WriteLine("Is {0} hidden?{1}", file, (attributes & FileAttributes.Hidden) != 0);            //  File.SetAttributes(file, FileAttributes.ReadOnly | FileAttributes.Hidden);            Action actions = Action.Read | Action.Delete;//未加Flags输出为5。Flags将把它视为一组位标志,输出Read,Delete            //Action actions = Action.Read & Action.Delete;            Console.WriteLine(actions.ToString());            FileAttributes fa = FileAttributes.System;            fa = fa.Set(FileAttributes.ReadOnly);            Console.ReadKey();        }    }    //17 & 13 = 10001 & 01101 = 00001 也就是1    //17 | 13 = 10001 | 01101 = 11101 也就是 29              [Flags]    internal enum Action    {        None = 0,        Read = 0x0001,        Write = 0x0002,        ReadWrite = Action.Read | Action.Write,        Delete = 0x0004,        Query = 0x0008,        Sync = 0x0010    }    internal static class FileAttributesExtensionMethods    {        public static Boolean IsSet(this FileAttributes flags, FileAttributes flagToTest)        {                return (flags & flagToTest) == flagToTest;        }        public static FileAttributes Set(this FileAttributes flags, FileAttributes setFlags)        {            return flags | setFlags;        }    }