Model-View-ViewModel in WPF

using System;
using System.Globalization;
using System.Windows.Data;

namespace TaskList
{
    public class TitleConverter : IValueConverter
    {
        #region IValueConverter Members

        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            string title = value.ToString();
            if (string.IsNullOrEmpty(title))
                return "Task List";
            return string.Format(CultureInfo.CurrentUICulture, "Task List - {0}", title);
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }

        #endregion
    }
}