Implements IEnumerator : IEnumerator : Class C# Examples

    
using  System;
using  System.Collections;

class  User  {
        public  User(string  name)  {  this.name  =  name;  }
        string  name;
        public  string  Name  {  get  {  return  name;  }  }
};

class  DBManager  :  IEnumerable  {
        public  DBManager()  {
                onlineUsers.Add(new  User("T"));
                onlineUsers.Add(new  User("K"));
                onlineUsers.Add(new  User("E"));
        }
        ArrayList  onlineUsers  =  new  ArrayList();

        public  IEnumerator  GetEnumerator()  {
                return  new  Enumerator(onlineUsers);
        }

        class  Enumerator  :  IEnumerator  {
                const  string  INVALID_RECORD  =  "Use  MoveNext  before  calling  Current";

                public  Enumerator(ArrayList  onlineUsers)  {
                        foreach  (User  user  in  onlineUsers)  {
                                this.onlineUsers.Add(user);
                        }
                        Reset();
                }
                ArrayList  onlineUsers  =  new  ArrayList();

                int  index;
                public  bool  MoveNext()  {
                        return  (++index  <  onlineUsers.Count);
                }

                public  object  Current  {
                        get  {
                                if  (-1  ==  index)
                                        throw  new  InvalidOperationException(INVALID_RECORD);
                                if  (index  <  onlineUsers.Count)
                                        return  onlineUsers[index];
                                else
                                        return  null;
                        }
                }
                public  void  Reset()  {  index  =  -1;  }
        }
        static  void  Main(string[]  args)  {
                DBManager  db  =  new  DBManager();
                IEnumerator  e  =  db.GetEnumerator();

                while  (e.MoveNext())  {
                        User  user  =  (User)e.Current;
                        Console.WriteLine("User={0}",  user.Name);
                }
        }
}