自定义延迟加载类

延迟加载类

 1     public class LazyLoader<TModel> where TModel:class

 2     {

 3         TModel _data;

 4         Func<TModel> _loadDataFunc = null;

 5         bool _loaded = false;

 6         public LazyLoader():this(null){ }

 7         public LazyLoader(Func<TModel> loadDataFunc) 

 8         {

 9             _loadDataFunc = loadDataFunc;

10             _data = null;

11             _loaded = false;

12         }

13         public TModel QueryData() 

14         {

15             if (!_loaded && _loadDataFunc != null)

16             {

17                 _data = _loadDataFunc();

18             }

19             return _data;

20         }

21         public void SetData(TModel value) 

22         {

23             _data = value;

24             _loaded = true;

25         }

26     }

LazyLoader

使用方法（简单举列）

比如员工菜单 可能你再使用这个员工对象的时候并不需要去加载他的菜单 当你要用的时候再加载 这时候就需要延迟加载了 

 1     public class Employee

 2     {

 3         public LazyLoader<IEnumerable<Menu>> _menus;

 4         public Employee(Guid employeeId, string employeeNo, string name, string password, string email, string phone, bool enabled,  bool isAdministrtor, DateTime registerDate, string remark, string ipLimitation)

 5         {

 6             EmployeeId = employeeId;

 7             EmployeeNo = employeeNo;

 8             Name = name;

 9             Password = password;

10             Email = email;

11             Phone = phone;

12             Enabled = enabled;

13             IsAdministrator = isAdministrtor;

14             RegisterDate = registerDate;

15             Remark = remark;

16             IpLimitation = ipLimitation;

17             _menus = new LazyLoader<IEnumerable<Menu>>(() => SystemResourceService.QueryMenusByEmployeeId(employeeId));

18         }

19 

20         public Guid EmployeeId { get; private set; }

21         public string EmployeeNo { get; private set; }

22         public string Name { get; private set; }

23         public string Password { get; private set; }

24         public string Email { get; private set; }

25         public string Phone { get; private set; }

26         public bool Enabled { get; set; }

27         public bool IsAdministrator { get; private set; }

28         public DateTime RegisterDate { get; private set; }

29         public string Remark { get; private set; }

30         public string IpLimitation { get; set; }

31         public object Id

32         {

33             get { return EmployeeId; }

34         }

35     }

Employee