Modeling M-V-VM

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Input;
using System.ComponentModel;

using WorldDataLib.Model;

namespace TestTreeViewWithRightBarView.ViewModel
{
     public class CityViewModel : ITreeViewNode, ICityViewModel, ISelectionSectionPresenter, INotifyPropertyChanged
     {
         #region Members

         IViewModel m_Parent;
         City m_City;

         #endregion

         #region Properties

         #region ITreeViewNode Members

         public string Caption
         {
             get 
             {
                 string str = string.Empty;
                 if (m_City != null)
                 {
                     str = m_City.Name;
                 }
                 return str; 
             }
         }        
        
         #endregion

         #region IViewModel Members

         public IViewModel VMParent
         {
             get 
             {
                 return m_Parent; 
             }
         }

         #endregion

         #region ISelectionSectionPresenter Members

         public string Title
         {
             get;
             set;
         }

         #endregion

         public double Temprature
         {
             get;
             set;
         }

         #endregion

         #region Methods   
     
         #region Ctor

         public CityViewModel(IViewModel parent, City city)
         {
             m_Parent = parent;
             m_City = city;
         }

         #endregion

         #region IViewModel Members

        public void HandleEvent(IViewModel sender, object param, ViewModelOperationsEnum viewModelEvent)
        {
            if (m_Parent != null)
            {
                m_Parent.HandleEvent(sender, param, viewModelEvent);
            }
        }

        #endregion

         #region GotFocus

         public ICommand GotFocus
         {
             get
             {
                 return new DelegateCommand(this.ControlGotFocus);
             }
         }

         /// <summary>
        /// When the control gets focus, an event is fired for external handling
        /// </summary>
        public void ControlGotFocus()
        {
            if (VMParent != null)
            {
                VMParent.HandleEvent(this, null, ViewModelOperationsEnum.GotFocus);
                VMParent.HandleEvent(this, Caption, ViewModelOperationsEnum.GetCityTemprature);
            }
        }

        #endregion

         #region ICityViewModel Members

        public void SetTemprature(double fTemprature)
        {
            Temprature = fTemprature;
            Title = string.Format("City: {0}. Current temprature: {1}", Caption, Temprature);
            OnPropertyChanged("Title");
        }         

        #endregion

        #endregion        

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string str)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(str));
            }
        }

        #endregion



        
     }
}