设计模式 - 线程安全的单例模式（C#）

标签：线程安全的单例模式   c#   

1、饿汉式单例模式

// 饿汉式单例模式 - by Chimomo
namespace CSharpLearning
{
    public sealed class Singleton
    {
        private static readonly Singleton instance = new Singleton();
        private Singleton() { }

        public static Singleton Instance
        {
            get { return instance; }
        }
    }
}

2、懒汉式单例模式

2.1、借助内部类

// 懒汉式单例模式：借助内部类 - by Chimomo
namespace CSharpLearning
{
    public sealed class Singleton
    {
        private Singleton() { }

        private static class SingletonHolder
        {
            public static readonly Singleton instance = new Singleton();
        }
        public static Singleton Instance
        {
            get { return SingletonHolder.instance; }
        }
    }
}

// 懒汉式单例模式：普通加锁 - by Chimomo
namespace CSharpLearning
{
    public sealed class Singleton
    {
        private static volatile Singleton instance;
        private static readonly object syncRoot = new object();
        private Singleton() { }
        public static Singleton Instance
        {
            get
            {
                lock (syncRoot)
                {
                    if (instance == null)
                    {
                        instance = new Singleton();
                    }
                }
                return instance;
            }
        }
    }
}

// 懒汉式单例模式：双重检测加锁 - by Chimomo
namespace CSharpLearning
{
    public sealed class Singleton
    {
        private static volatile Singleton instance;
        private static readonly object syncRoot = new object();
        private Singleton() { }
        public static Singleton Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (syncRoot)
                    {
                        if (instance == null)
                        {
                            instance = new Singleton();
                        }
                    }
                }
                return instance;
            }
        }
    }
}

设计模式 - 线程安全的单例模式（C#）

标签：线程安全的单例模式   c#   

原文地址：http://blog.csdn.net/troubleshooter/article/details/41480349