MVVM for Multi Platforms

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

namespace GeographicRepresentation.Interfaces
{
    /// <summary>
    /// Present data of a city
    /// </summary>
    public interface ICityViewModel
    {
        #region Properties

        /// <summary>
        /// A unique key for specifying the city. This property can't be edited
        /// </summary>
        Guid Id
        {
            get;
        }

        string CityName
        {
            get;
            set;
        }

        int Population
        {
            get;
            set;
        }

        /// <summary>
        /// The difference of the Time zone
        /// </summary>
        short TimeZone
        {
            get;
            set;
        }

        #endregion 

        #region Methods

        /// <summary>
        /// Get the current time in the destination
        /// </summary>
        /// <returns></returns>
        DateTime GetCurrentTime();

        #endregion
    }

    /// <summary>
    /// This interface presents a view model for simply viewing data over the city, without the ability to change it
    /// </summary>
    public interface IReadOnlyCityViewModel : ICityViewModel, IReadOnlyViewModel
    {
        
    }

    /// <summary>
    /// This interface presents a view model for adding or editing data over a city
    /// </summary>
    public interface IEditableCityViewModel : ICityViewModel, IEditableObject
    {
    }
}