c# - How to perform method -

i have class person, 2 child classes staff , student, interface iperson. have class database , class gateway. class database has

private string name = "username"; 

and method

public void getname() {return id;} 

both staff , student have getname() methods. need create request getname() student , staff classes database through gateway. class gateway has check if method getname() requested staff (then return id) or student (then return "go away!"). can please me that. thinking using gateway interface of database class, because trying learn c#, don't know how that. or maybe there's better way of doing this... please thanks

here's code:

public class staff : person   {       public staff() {}     public staff(string id): base(id) {}     public override string getname()     {         throw new notimplementedexception();     }     public override void update(object o)     {       console.writeline(id + " notified {1}", id, o.tostring());      }     public override void updatemessage(object p)     {       console.writeline(id + " notified new message in chat: {1}", id, p.tostring());      }   } 

---

public class student : person {     public student() {}     public student(string id): base(id) {}     public override string getname()     {         throw new notimplementedexception();     }     public override void update(object o)      {      console.writeline(id +"  notified {1}", id, o.tostring());     }     public override void updatemessage(object p)      {      console.writeline("message " + id + "  {1}", id, p.tostring());     } } 

---

 public abstract class person : iperson {     public string id;     public person() { }     public abstract string getname();     public person(string i) { this.id = i; }     public abstract void update(object o);     public abstract void updatemessage(object p); }  public interface iperson       {    void update(object o);    void updatemessage(object p);    string getname();  } 

---

 class database  {      public string username = "username";      private string name =  "user details";      private string grade = "user grade";       public string getname(object o)      {          if (o staff) { return name; }          else { return "go away!"; }      }      public string getgrade() { return grade; }  }    public class gateway    {     public void dosomethingwithperson(iperson person)     {         string id = person.getname();         if (person student)         {             return "go away!";         }         else if (person staff)         {             return name;         }     } } 

this convoluted question. so, first off, i'd point out few style issues c#.

• your database class lowercase while rest cased consistently. methods inconsistent (for example, use idiomatic pascalcase methods, , camelcase or lowercase others).
• iperson has no purpose here because can pass instances of staff , student around person , use in same way now. in cases, you'll want choose either interface or abstract base class, not both.
• c# has notion of "properties", convenient syntax getters , setters. preferred public fields (as in public string username in database class or public string id in person) because allows keep implementation of backing field private. syntax public string username { get; set; } if want default implementation. can expand more complicated things. example, maybe want ensure username trimmed. (1)
• minor nitpick, typically object lowercase o used.
• you don't have call .tostring() on objects in string formatting interpolation. (2)

(1)

private string m_username; public string username {     { return m_username; }     set { m_username = (value != null ? value.trim() : value); } } 

(2) these lines equivalent.

console.writeline(id + " notified {1}", id, o.tostring()); console.writeline("{0} notified {1}", id, o); 

now on problem. me, sounds want different behavior different classes. way it's phrased, sounds access/permissions issue. depending on how data store set (in case, looks constants in code, kind of query), like...

[flags] public enum permission {     none = 0,     getname = 1 }  public abstract class person {     /* ... */     public abstract permission permissions { get; } }  public class staff : person {     /* ... */     public override permission permissions {         { return permission.getname; }     } }  public class student : person {     /* ... */     public override permission permissions {         { return permission.none; }     } }  public class database {     /* ... */     private dictionary<string, string> namesdatabase { get; set; }     public string getname(string id) {         // consequence of being managed gateway, assume caller has access         return namesdatabase[id];     } }  public class gateway {     public string dosomethingwithperson(person person, string desirednamepersonid) {         if (person.permissions.hasflag(permission.getname)) {             database db = new database();             return db.getname(desirednamepersonid);         }         return "go away!";     } } 

supposing have constructor database such:

    public database() {         namesdatabase = new dictionary<string, string>(2);         namesdatabase["id1"] = "student amy";         namesdatabase["id2"] = "staff mary";     } 

and main such:

    static void main() {         gateway gate = new gateway();         console.writeline("student id1 looks staff id2: {0}", gate.dosomethingwithperson(new student("id1"), "id2"));         console.writeline("staff id2 looks student id1: {0}", gate.dosomethingwithperson(new staff("id2"), "id1"));          console.readline();     } 

the output is:

 student id1 looks staff id2: go away!  staff id2 looks student id1: student amy 

feel free ask clarifying questions if part unclear or i'm way off mark in assessment.