MVVM for Multi Platforms

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

using GeographicRepresentation.Lib;
using GeographicRepresentation.Interfaces;
using System.Threading;

namespace GeographicRepresentation.UILib.View
{
    /// <summary>
    /// Interaction logic for EditCityWindow.xaml
    /// </summary>
    public partial class EditCityWindow : Window, IDisposable    
    {
        #region Members

        Guid m_Id;
        bool m_bNew;
        IEditableCityViewModel m_DataContext;
        Timer m_Timer;
        DateTime m_CurrentTime;           

        public static RoutedUICommand cmd_SaveCity = new RoutedUICommand("saveCity", "saveCity", typeof(EditCityWindow));
        public static RoutedUICommand cmd_Cancel = new RoutedUICommand("cancelCity", "cancelCity", typeof(EditCityWindow));

        #endregion

        #region Methods

        #region Ctor
        
        /// <summary>
        /// Default Ctor
        /// </summary>
        /// <param name="bNew">a flag which determines if the purpose of the window is to create a new city or to edit an
        ///                    existing one</param>
        /// <param name="id">the id - country if new, city if edit</param>
        public EditCityWindow(bool bNew, Guid id)
        {
            m_bNew = bNew;
            m_Id = id;
            InitializeComponent();
            m_Timer = new Timer(this.GetCityTime);
        }
        

        #endregion

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            SimpleOperationDelegate delg = new SimpleOperationDelegate(this.GetDataContext);
            delg.BeginInvoke(new AsyncCallback(this.DataContextLoaded), delg);

            if (m_bNew)
            {
                this.Title = "Add city";
            }

            CommandBinding cb = new CommandBinding(cmd_SaveCity, onSave, canSave);
            CommandBindings.Add(cb);
            cb = new CommandBinding(cmd_Cancel, onCancel, canCancel);
            CommandBindings.Add(cb);
        }        

        /// <summary>
        /// A request for the data context
        /// </summary>
        private void GetDataContext()
        {
            if (m_bNew)
            {
                m_DataContext = InterfacesFactory.Instance.GetEditableCityViewModelForAdd(m_Id);
            }
            else
            {
                m_DataContext = InterfacesFactory.Instance.GetEditableCityViewModelForEdit(m_Id);
            }
        }

        /// <summary>
        /// The data context call back. Make all the adjustments in the main thread, using the dispatcher
        /// </summary>
        /// <param name="result"></param>
        private void DataContextLoaded(IAsyncResult result)
        {
            System.Windows.Application.Current.Dispatcher.BeginInvoke(new AsyncCallback(this.DataContextLoadedInMainThread), result);
        }

        /// <summary>
        /// Update the view
        /// </summary>
        /// <param name="result"></param>
        private void DataContextLoadedInMainThread(IAsyncResult result)
        {
            if (result.IsCompleted)
            {
                this.DataContext = m_DataContext;
                SimpleOperationDelegate delg = result.AsyncState as SimpleOperationDelegate;
                delg.EndInvoke(result);                
                Button saveButton = (Button)this.Template.FindName("saveButton", this);
                if (saveButton != null)
                {
                    saveButton.Command = EditCityWindow.cmd_SaveCity;
                }
                Button cancelButton = (Button)this.Template.FindName("cancelButton", this);
                if (cancelButton != null)
                {
                    cancelButton.Command = EditCityWindow.cmd_Cancel;
                }
                if (!m_bNew)
                {                    
                    this.Title = string.Format("Edit {0}", m_DataContext.CityName);
                    m_Timer.Change(1000, 1000);
                }                
            }
        }

        /// <summary>
        /// Use the view model to request data
        /// </summary>
        /// <param name="state"></param>
        private void GetCityTime(object state)
        {
            m_CurrentTime = m_DataContext.GetCurrentTime();
            // update the data from the main window
            System.Windows.Application.Current.Dispatcher.BeginInvoke(new SimpleOperationDelegate(this.UpdateCurrentTime));
        }

        private void UpdateCurrentTime()
        {
            this.Title = string.Format("Edit {0}. Current time at city {1}", m_DataContext.CityName, m_CurrentTime.ToLongTimeString());
        }

        private void onSave(object sender, ExecutedRoutedEventArgs args)
        {
            this.Cursor = Cursors.Wait;
            SimpleOperationDelegate delg = new SimpleOperationDelegate(this.SaveOperation);
            delg.BeginInvoke(this.OperationCompleted, delg);
        }

        /// <summary>
        /// Textual data validation
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="args"></param>
        private void canSave(object sender, CanExecuteRoutedEventArgs args)
        {
            int n;
            args.CanExecute = txtName.Text.Length > 0 &&
                              int.TryParse(txtPopulation.Text, out n) &&                              
                              n > 0;
        }       

        private void SaveOperation()
        {
            m_DataContext.Save();
        }

        /// <summary>
        /// The operation call back. Call the dispatcher to update the view from the main thread
        /// </summary>
        /// <param name="result"></param>
        private void OperationCompleted(IAsyncResult result)
        {
            System.Windows.Application.Current.Dispatcher.BeginInvoke(new AsyncCallback(this.EndOperation), result);
        }

        /// <summary>
        /// End the asynchronos call
        /// </summary>
        /// <param name="result"></param>
        private void EndOperation(IAsyncResult result)
        {
            this.Cursor = Cursors.Arrow;

            SimpleOperationDelegate delg = result.AsyncState as SimpleOperationDelegate;
            delg.EndInvoke(result);
            this.DialogResult = true;
            this.Close();   
        }

        /// <summary>
        /// The cancelation button should run if this is the edit mode, othewise, simply close the window
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="args"></param>
        private void onCancel(object sender, ExecutedRoutedEventArgs args)
        {
            if (!m_bNew)
            {
                this.Cursor = Cursors.Wait;
                SimpleOperationDelegate delg = new SimpleOperationDelegate(this.CancelOperation);
                delg.BeginInvoke(this.OperationCompleted, delg);
            }
            else
            {
                this.Close();
            }
        }


        private void canCancel(object sender, CanExecuteRoutedEventArgs args)
        {
            args.CanExecute = true;
        }

        private void CancelOperation()
        {
            m_DataContext.Cancel();
        }

        #region IDisposable Members

        public void Dispose()
        {
            if (m_Timer != null)
            {
                m_Timer.Change(Timeout.Infinite, Timeout.Infinite);
                m_Timer.Dispose();
            }
        }

        #endregion        

        #endregion

        
    }

    /// <summary>
    /// Create a collection for the data to present it in the XAML as an object data provider
    /// </summary>
    public class UTCTimePresenterCollection
    {
        public IList<short> GetValues()
        {
            List<short> list = new List<short>();
            for (short iter = -12; iter < 12; iter++)
            {
                list.Add(iter);
            }
            return list;
        }
    }
}