类成员怎么获取类对象实例

类成员如何获取类对象实例
    class Company
    {
        List<Department> deptList;

        private List<Department> DeptList
        {
            get { return deptList; }
            set { deptList = value; }
        }

    }
    class Department
    {
        private Company parent;

        internal Company Parent
        {
            get 
            {
                //这里怎么写才能获得当前Company的对象实例？？？
            }
            //set { parent = value; }
        }
    }
[解决办法]
class Department
     {
        private Company _parent;

        public Department(Company parent)
        {
             this._parent = parent;
        }

        internal Company Parent
         {
             get 
             { return this._parent;}
             //set { _parent = value; }
         }
     } 

在Company类中，给List<Department>赋值时使用带参的构造函数来New Department(this)
如果Department的无参构造是必需的，使用Department.Parent时就判断下是否为null
[解决办法]
真要较真的话就做成静态的

 class Company
    {
     private static Company _Company;
      public static Company Company
      {
         get;
      }

   
        List<Department> deptList;

        private List<Department> DeptList
        {
            get { return deptList; }
            set { deptList = value; }
        } 
 

    }