Modeling M-V-VM

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

using WorldDataLib.Model;

namespace TestTreeViewWithRightBarView.ViewModel
{
    public class CountryViewModel : ITreeViewWithChildrenNode, ICountryViewModel, ISelectionSectionPresenter, INotifyPropertyChanged
    {
        #region Members

        IViewModel m_Parent;
        Country m_Country;
        ObservableCollection<ITreeViewNode> m_Children;

        #endregion

        #region Properties

        #region ITreeViewWithChildrenNode Members

        public ObservableCollection<ITreeViewNode> Children
        {
            get 
            {
                return m_Children; 
            }
        }

        #endregion

        #region ITreeViewNode Members

        public string Caption
        {
            get 
            {
                string str = string.Empty;
                if (m_Country != null)
                {
                    str = m_Country.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 CurrenciesEnum Currency
        {
            get;
            set;
        }

        #endregion

        #region Methods

        #region Ctor

        public CountryViewModel(IViewModel parent, Country country)
        {
            m_Parent = parent;
            m_Country = country;
            m_Children = new ObservableCollection<ITreeViewNode>();
            if ((m_Country != null) && (m_Country.Cities != null))
            {
                for(int iter = 0; iter < m_Country.Cities.Count; iter++)
                {
                    m_Children.Add(new CityViewModel(this, m_Country.Cities[iter]));
                }
            }
        }

        #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.GetCountryCurrency);
            }
        }

        #endregion

        #region ICountryViewModel Members

        public void SetCurrency(CurrenciesEnum currency)
        {
            Currency = currency;
            Title = string.Format("{0} currency is {1}",Caption, Currency);
            OnPropertyChanged("Title");
        }

        #endregion

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

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

        #endregion

        #endregion



    }
}