Attributes

參考網站

using OnLineGame;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace CustomizedAttributesDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            AttributeLinqSample();
            Console.ReadLine();
        }

        static void AttributeLinqSample()
        {
            // Get all the Types which apply GamerB1Attribute
            // IEnumerable 是一個 Collection
            IEnumerable<System.Type> types = from t in Assembly.GetExecutingAssembly().GetTypes()
                                                 //where t.GetCustomAttributes<GamerB1Attribute>().Any() //這兩種寫法的意思是一樣的
                                             where t.GetCustomAttributes<GamerB1Attribute>().Count() > 0
                                             select t;
            Console.WriteLine("****** 以下列出所有套用 GamerB1Attribute 的 Class ******");

            foreach (Type t in types)
            {

                Console.WriteLine("Namespace：" + t.Namespace + "底下的：" + t.Name);
                Console.WriteLine("包含所有的 Property 如下：");
                foreach (PropertyInfo propertyInfo in t.GetProperties())
                {
                    Console.WriteLine("型別：" + propertyInfo.PropertyType.Name + ", Property名稱：" + propertyInfo.Name);
                }
                Console.WriteLine("");
                Console.WriteLine("包含所有的 Method 如下：");
                foreach (MethodInfo methodInfo in t.GetMethods())
                {
                    Console.WriteLine("型別：" + methodInfo.ReturnType.Name + ", Method名稱：" + methodInfo.Name);
                }

                Console.WriteLine("");
                Console.WriteLine("以上這些 Property 中，僅有Apply GamerB1Attribute 的 Property 如下：");
                IEnumerable<PropertyInfo> gamerB1AttributePropertyInfo = from pInfo in t.GetProperties()
                                                                         where pInfo.GetCustomAttributes<GamerB1Attribute>().Any()
                                                                         select pInfo;
                foreach (PropertyInfo propertyInfo in gamerB1AttributePropertyInfo)
                {
                    Console.WriteLine("型別：" + propertyInfo.PropertyType.Name + ", Method名稱：" + propertyInfo.Name);
                }

                Console.WriteLine("");
                Console.WriteLine("以上這些 Method 中，僅有Apply GamerB1Attribute 的 Method 如下：");
                IEnumerable<MethodInfo> gamerB1AttributeMethodInfo = from mInfo in t.GetMethods()
                                                                     where mInfo.GetCustomAttributes<GamerB1Attribute>().Any()
                                                                     select mInfo;
                foreach (MethodInfo methodInfo in gamerB1AttributeMethodInfo)
                {
                    Console.WriteLine("型別：" + methodInfo.ReturnType.Name + ", Method名稱：" + methodInfo.Name);
                }

                Console.WriteLine("");
            }
        }
    }
}


namespace OnLineGame
{
    //[AttributeUsage(AttributeTargets.All)] <-- 這行其實可以不用特別寫出來，因為預設就是這個
    //[AttributeUsage(AttributeTargets.All)] 代表的意思是可以被用在任何地方
    //例如：AttributeUsage(AttributeTargets.Class | AttributeTargets.Property | AttributeTargets.Method | ...etc.)]
    [AttributeUsage(AttributeTargets.All)]
    public class GamerA1Attribute : Attribute
    {
    }

    //也可以寫成 [GamerA1Attribute]，但是就多此一舉
    [GamerA1]
    public class GamerA
    {
        #region Properties
        [GamerA1]
        public int GameScore { get; set; }
        [GamerA1]
        public string Name { get; set; }
        #endregion

        #region Methods
        [GamerA1]
        public override string ToString()
        {
            return $"GameScore : {GameScore} ; Name : {Name}";
        }
        public void NoAttributeMethod()
        {
        }
        #endregion
    }

    // GamerB1Attribute 這個 Attribute 只能被用在 Class、Property、Method
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Property | AttributeTargets.Method)]
    public class GamerB1Attribute : Attribute
    {
        #region Property
        public string Name { get; set; }
        public double Version { get; set; }
        #endregion
    }

    // GamerB 這個 Class 套用了 GamerB1Attribute 這個 Attribute
    // 同時宣告了2個 Attribute 的值
    [GamerB1(Name = "GamerB", Version = 1.0)]
    public class GamerB
    {
        #region Property
        [GamerB1(Name = "GamerBMethod", Version = 1.0)]
        public int GameScore { get; set; }
        [GamerA1]
        public string Name { get; set; }
        #endregion
        #region Methods
        [GamerB1]
        public override string ToString()
        {
            return $"GameScore : {GameScore} ; Name : {Name}";
        }
        public void NoAttributeMethod()
        {
        }
        #endregion
    }
    [GamerB1(Name = "GamerB2", Version = 1.0)]
    public class GamerB2
    {
        #region Property
        [GamerB1(Name = "GamerB2Method", Version = 1.0)]
        public int GameScore { get; set; }
        [GamerA1]
        public string Name { get; set; }
        #endregion
        #region Methods
        [GamerB1]
        public override string ToString()
        {
            return $"GameScore : {GameScore} ; Name : {Name}";
        }
        #endregion
    }
}