c# - How to structure two classes that "intersect" and output certain values (Mediator design pattern)? -

i have 2 classes: user , site. user , site have many-to-many relationship. site object s has property indicating whether or not user u should validated before u added s. validate user, application retrieves validation rules site , checks see user's properties' values match validation rules' values. if match/pass, user "valid" added site.

how structure relationship? first thought create intermediate class (i.e. mediator design pattern?) has field of type ienumerable<user> , site can encapsulate site validation setting retrieval. also, i'm thinking of adding "isvalid" property user class. need? want make sure things not tightly coupled.

thoughts?

here's similar code wrote up:

public class user {     public int _userid;     public string _fname;     public string _lname;      public user(string connectionstring, int id)     {         using (var dc = new datacontext(connectionstring))         {             var user = dc.users.singleordefault(u => u.id == id);             _userid = user.id;             _fname = user.fname;             _lname = user.lname;         }     }      public bool isvaliduser(int siteid)     {         bool isvalid = true;         // logic here won't change         var conditions = site.getconditions(_userid);         // e.g. checks _fname, _lname         return site.usermeetsconditions(_id, conditions);     } }  public class site {     public int _siteid;     public list<setting> _sitesettings;      public site(string connectionstring, int id)     {         using (var dc = new datacontext(connectionstring))         {             var site = dc.sites.singleordefault(u => u.id == id);             _siteid = site.id;         }     }      public void setsitesettings(string connectionstring)     {         using (var dc = new datacontext(connectionstring))         {             _sitesettings = dc.sitesettings.select(s => s).tolist();         }     }      public bool siterequiresvaliditycheck()     {         return _sitesettings.any(s => s.settingid = 100 && s.value == true);     } }  public validator {     public list<user> users;     public bool _requiresvaliditycheck;      public bool usersarevalid(int siteid)     {         bool usersarevalid = true;         if (_requiresvaliditycheck)         {             foreach (var user in users)             {                 if (!user.isvalid)                 {                     usersarevalid = false;                     break;                 }             }         }          return usersarevalid;     } }  static void main() {     string cs = myconnectionstring;     var user1 = new user(cs, 1);     var user2 = new user(cs, 2);     list<user> users = new list<user>() { user1, user2 };     var site = new site(cs, 10);     site.setsitesettings(cs);     var validator = new validator();     validator.users = users;     validator._requiresvaliditycheck = site.siterequiresvaliditycheck();      bool usersarevalid = validator.usersarevalid(site._siteid);  } 

if poco class or model use dataannotations on class attributes. user

[required]  

etc attributes each attribute. data annotations has support cross attribute checking can implement too. take @ them here: https://msdn.microsoft.com/en-us/library/dd901590%28vs.95%29.aspx