Modeling M-V-VM

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

using WorldDataLib.Model;

namespace TestTreeViewWithRightBarView.ViewModel
{


    public class MainViewModel : IViewModel, INotifyPropertyChanged
    {
        #region Helper Classes

        private delegate void VMEventHandler(IViewModel sender, object param);

        #endregion

        #region Members

        /// <summary>
        /// A dictionary which holds delegates for handling the events
        /// </summary>
        Dictionary<ViewModelOperationsEnum, VMEventHandler> m_EventHandler;
        ObservableCollection<TreeRootViewModel> m_TreeRootViewModel;        

        #endregion

        #region Properties

        public ObservableCollection<TreeRootViewModel> TreeRootViewModel
        {
            get 
            { 
                return m_TreeRootViewModel; 
            }
        }

        /// <summary>
        /// The currently selected Tree node
        /// </summary>
        public ITreeViewNode CurrentNode
        {
            get;
            set;
        }

        #endregion

        #region Methods

        #region Ctor

        public MainViewModel()
        {
            m_EventHandler = new Dictionary<ViewModelOperationsEnum, VMEventHandler>();
            m_TreeRootViewModel = new ObservableCollection<TreeRootViewModel>();            
            InitEventHandlers();
            LoadDataFromFile();
        }

        #endregion

        #region IViewModel Members

        public IViewModel VMParent
        {
            get 
            {
                throw new NotImplementedException(); 
            }
        }

        /// <summary>
        /// Upon a comming event, check if it appears in the hanlder dictionary
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="param"></param>
        /// <param name="viewModelEvent"></param>
        public void HandleEvent(IViewModel sender, object param, ViewModelOperationsEnum viewModelEvent)
        {
            VMEventHandler handler;
            if (m_EventHandler.TryGetValue(viewModelEvent, out handler))
            {
                handler(sender, param);
            }
        }

        #endregion

        #region Event Handlers

        private void InitEventHandlers()
        {
            m_EventHandler.Add(ViewModelOperationsEnum.GotFocus, this.ControlGotFocus);
            m_EventHandler.Add(ViewModelOperationsEnum.GetContinentSize, this.GetContinentSize);
            m_EventHandler.Add(ViewModelOperationsEnum.GetCountryCurrency, this.GetCounrtyCurrency);
            m_EventHandler.Add(ViewModelOperationsEnum.GetCityTemprature, this.GetCityTemprature);
        }

        /// <summary>
        /// When an event of Got Focus appears. The current node should be updated
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="param"></param>
        public void ControlGotFocus(IViewModel sender, object param)
        {
            ITreeViewNode node = sender as ITreeViewNode;
            if (node != null)
            {
                CurrentNode = node;
                OnPropertyChanged("CurrentNode");
            }
        }

        public void GetContinentSize(IViewModel sender, object param)
        {
            using (WorldServiceReference.WorldDataServiceClient client = new TestTreeViewWithRightBarView.WorldServiceReference.WorldDataServiceClient())
            {
                double size = client.GetContinentSizeInSquareMiles(param as string);
                IContinentViewModel vm = sender as IContinentViewModel;
                if (vm != null)
                {
                    vm.SetSize(size);
                }
            }
        }

        public void GetCounrtyCurrency(IViewModel sender, object param)
        {
            using (WorldServiceReference.WorldDataServiceClient client = new TestTreeViewWithRightBarView.WorldServiceReference.WorldDataServiceClient())
            {
                CurrenciesEnum currency = client.GetCountryCurrency(param as string);
                ICountryViewModel vm = sender as ICountryViewModel;
                if (vm != null)
                {
                    vm.SetCurrency(currency);
                }
            }
        }

        public void GetCityTemprature(IViewModel sender, object param)
        {
            using (WorldServiceReference.WorldDataServiceClient client = new TestTreeViewWithRightBarView.WorldServiceReference.WorldDataServiceClient())
            {
                double temprature = client.GetCityCurrentTemprature(param as string);
                ICityViewModel vm = sender as ICityViewModel;
                if (vm != null)
                {
                    vm.SetTemprature(temprature);
                }
            }
        }

        #endregion

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

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

        #endregion

        private void LoadDataFromFile()
        {
            List<Continent> continents = null;

            System.Xml.Serialization.XmlSerializer serialzer = new System.Xml.Serialization.XmlSerializer(typeof(List<Continent>));
            System.IO.Stream stream = null;
            try
            {
                stream = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream("TestTreeViewWithRightBarView.Resources.Continents.xml");
                continents = (List<Continent>)serialzer.Deserialize(stream);
                m_TreeRootViewModel.Add(new TreeRootViewModel(this, continents));
            }
            catch (Exception)
            {
            }
            finally
            {
                if (stream != null)
                {
                    stream.Close();
                }
            }
            
        }

        #endregion

        
    }
}