c# 反射（1）

 /// 1 dll-IL-metadata-反射
 /// 2 反射加载dll，读取module、类、方法、特性
 /// 3 破坏单例 创建泛型
namespace MyReflection
{
    class Program
    {
       
        static void Main(string[] args)
        {
            #region Reflection
            {
                Assembly assembly = Assembly.Load("DB.Mysql");
                //1 动态加载 一个完整dll名称不需要后缀  从exe所在的路径进行查找
                Assembly assembly1 = Assembly.LoadFile(@"E:\MyReflection\MyReflection\bin\Debug\DB.Mysql.dll");//完整路径
                Assembly assembly2 = Assembly.LoadFrom("DB.Mysql.dll");//当前路径
                Assembly assembly3 = Assembly.LoadFrom(@"E:\MyReflection\MyReflection\bin\Debug\DB.Mysql.dll");//当前路径

                foreach (var type in assembly.GetTypes())
                {
                    //type.IsGenericType
                    Console.WriteLine(type.Name);       //类名
                    foreach (var method in type.GetMethods())
                    {
                        Console.WriteLine(method.Name);//方法名
                    }
                }
            }
            #endregion

            #region MyRegion
            {
                Assembly assembly = Assembly.Load("DB.Mysql");         //1 动态加载
                Type type = assembly.GetType("DB.Mysql.MySqlHelper");//2 获取类型 完整类型名称
                object oDBHelper = Activator.CreateInstance(type);//3 创建对象

                //oDBHelper.Query();
                //不能直接Query  ,实际上oDBHelper是有Query方法的，只是因为编译器不认可
                //C#是一种强类型语言，静态语言，编译时就确定好类型保证安全
                //dynamic dDBHelper= Activator.CreateInstance(type);
                //dDBHelper.Query();//dynamic编译器不检查，，运行时才检查
                IDBHelper iDBHelper = oDBHelper as IDBHelper;//4 类型转换  不报错，类型不对就返回null
                iDBHelper.Query();//5 方法调用
            }
            #endregion
            {
                Console.WriteLine("**************ctor&parameter*************");
                Assembly assembly = Assembly.Load("DB.Mysql");
                Type type = assembly.GetType("DB.Mysql.MySqlHelper");
                foreach (ConstructorInfo ctor in type.GetConstructors())
                {
                    Console.WriteLine(ctor.Name);
                    foreach (var parameter in ctor.GetParameters())
                    {
                        Console.WriteLine(parameter.ParameterType);   //构造函数参数类型
                    }
                }
                object oTest1 = Activator.CreateInstance(type);
                object oTest2 = Activator.CreateInstance(type, new object[] { 123 });  //调用有参数构造函数
                object oTest3 = Activator.CreateInstance(type, new object[] { "陌殇" });
            }
            {
                //反射破坏单例---就是发射调用私有构造函数
                Assembly assembly = Assembly.Load("DB.Mysql");
                Type type = assembly.GetType("DB.Mysql.Singleton");
                Singleton singletonA = (Singleton)Activator.CreateInstance(type, true);
                Singleton singletonB = (Singleton)Activator.CreateInstance(type, true);
                Console.WriteLine($"{object.ReferenceEquals(singletonA, singletonB)}");
            }
            #region 反射创建泛型
            {
                Assembly assembly = Assembly.Load("DB.Mysql");
                Type type = assembly.GetType("DB.Mysql.Generic`3");
                Type typeMake = type.MakeGenericType(new Type[] { typeof(string), typeof(int), typeof(DateTime) });
                object oGeneric = Activator.CreateInstance(typeMake);
            }
            #endregion
            Console.ReadKey();
        }
    }
}

namespace DB.Interface
{
    public interface IDBHelper
    {
        void Query();
    }
}

namespace DB.Mysql
{
    public class MySqlHelper : IDBHelper
    {
        public string name { get; set; }
        public MySqlHelper()
        {
            Console.WriteLine("{0}被构造", this.GetType().Name);
        }
        /// <summary>
        /// 带参数构造函数
        /// </summary>
        /// <param name="name"></param>
        public MySqlHelper(string name)
        {
            Console.WriteLine("这里是{0} 有参数构造函数", this.GetType());
        }

        public MySqlHelper(int id)
        {
            Console.WriteLine("这里是{0} 有参数构造函数", this.GetType());
        }

        public void Test()
        {
            Console.WriteLine("");
        }

        public void Query()
        {
            Console.WriteLine("{0}.Query", this.GetType().Name);
        }
    }
    public class SqlServerHelper
    {
        public SqlServerHelper()
        {
            Console.WriteLine("{0}被构造", this.GetType().Name);
        }
    }
}

namespace DB.Mysql
{
    public sealed class Singleton
    {
        private static Singleton _Singleton = null;
        private Singleton()
        {
            Console.WriteLine("Singleton被构造");
        }

        static Singleton()
        {
            _Singleton = new Singleton();
        }

        public static Singleton GetInstance()
        {
            return _Singleton;
        }
    }
}

namespace DB.Mysql
{
    public class MySqlHelper : IDBHelper
    {
        public string name { get; set; }
        public MySqlHelper()
        {
            Console.WriteLine("{0}被构造", this.GetType().Name);
        }
        /// <summary>
        /// 带参数构造函数
        /// </summary>
        /// <param name="name"></param>
        public MySqlHelper(string name)
        {
            Console.WriteLine("这里是{0} 有参数构造函数", this.GetType());
        }

        public MySqlHelper(int id)
        {
            Console.WriteLine("这里是{0} 有参数构造函数", this.GetType());
        }

        public void Test()
        {
            Console.WriteLine("");
        }

        public void Query()
        {
            Console.WriteLine("{0}.Query", this.GetType().Name);
        }
    }
    public class SqlServerHelper
    {
        public SqlServerHelper()
        {
            Console.WriteLine("{0}被构造", this.GetType().Name);
        }
    }
}