设计模式之单例模式代码示例

using System;
namespace SingletonFunc{
    public class Singleton{

        private static object obj = new object();
        private static Singleton singleton;

        public static Singleton CreateSingleton()
        {
            if(singleton == null){
                lock(obj)
                {
                    if(singleton == null)
                    {
                        singleton = new Singleton();
                    }
                }
            }
            return singleton;
        }
        
        public override bool Equals(object obj)
        {
            if(obj == null) return false;
            if(singleton == obj as Singleton) return true;
            else 
                return false;
        }
    }

    public class EntryPoint{
        
        public static void Main(string[] args){
            Singleton singleton1 = Singleton.CreateSingleton();
            Singleton singleton2 = Singleton.CreateSingleton();
//            bool compare = System.Object.ReferenceEquals(singleton1,singleton2);
            bool compare = System.Object.Equals(singleton1,singleton2);
            compare = singleton1.Equals(singleton2);
            if(compare){
                Console.Write("true");
            }
            else{
                Console.Write("false");
            }
            Console.Read();
        }
    }
}