单例类的构造

    public class DataHelp
    {
        private static object objLock = new object();
        private static DataHelp instance = null;
        public static DataHelp Instance
        {
            get 
            {
                if (instance == null)
                {
                    lock (objLock)
                    {
                        if (instance == null)
                        {
                            instance = new DataHelp();
                        }
                    }
                }

                return instance;
            }
        }

        // DataHelp 非静态构造函数与方法
        private DataHelp()
        { 
        }

        public void DoSomething()
        { 
        }

        ...
    }

DataHelp.Instance.DoSomething();