C# 工厂单例

 public class BusinessFactory
    {
        private static BusinessFactory instance = null;
        private static readonly object syncObj = new object();

        /// <summary>  
        /// 业务逻辑创建工厂实例
        /// </summary>
        public static BusinessFactory Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (syncObj)
                    {
                        if (instance == null)
                        {
                            instance = new BusinessFactory();
                        }
                    }
                }

                return instance;
            }
        }


        //下边定义方法来产生你的业务逻辑实体

        #region"个人事务--大事记管理"
        /// <summary>
        /// 个人事务
        /// 公司大记事
        /// </summary>
        /// <returns></returns>
        public ICompanyBigEventBLL CreateCompanyBigEvent()
        {
            return new CompanyBigEventBLL();
        }