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public class Singleton { private static Singleton _instance = null; private Singleton(){} public static Singleton CreateInstance() { if(_instance == null) { _instance = new Singleton(); } return _instance; } } 第二种考虑了线程安全，不过有点烦，但绝对是正规写法，经典的一叉 public class Singleton { private volatile static Singleton _instance = null; private static readonly object lockHelper = new object(); private Singleton(){} public static Singleton CreateInstance() { if(_instance == null) { lock(lockHelper) { if(_instance == null) _instance = new Singleton(); } } return _instance; } } 第三种可能是C#这样的高级语言特有的，实在懒得出奇 public class Singleton { private Singleton(){} public static readonly Singleton instance = new Singleton(); } 哦，shit！标签：
原文地址：http://www.cnblogs.com/dullbaby/p/4763097.html
