public class PrpertiesWindowViewModel : BaseViewModel
      {
        private string name;
        public string Name 
        {
          get { return name; }
          set
          {
            name = value; 
            OnPropertyChanged("Name");
            OnPropertyChanged("IsEnabled");
          }
        }
        private string address;
        public string Address
        {
          get { return address; }
          set
          {
            address = value;
            OnPropertyChanged("Address");
            OnPropertyChanged("IsEnabled");
          }
        }
        private readonly ICommand buttonCommand;
        public ICommand ButtonCommand
        {
          get { return this.buttonCommand; }
        }
        public List<int> Rooms { get; set; }
        public PrpertiesWindowViewModel()
        {
          Rooms = new List<int>();
          FillList();
         
          this.buttonCommand = new RelayCommand(CmdExec, CanCmdExec);
        }
        private void CmdExec(object parameter)
        {
          // Code to save data here.
          MessageBox.Show(" clicked ");
         
    
        }
        private bool CanCmdExec(object obj) => true;
    
        public bool IsEnabled
        {
          get
          {
            return !(((string.IsNullOrEmpty(this.Name)) || (string.IsNullOrEmpty(this.Address)) ));
          }
        }
        private void FillList()
        {
    
          for (int i = 1; i < 50; i++)
          {
            Rooms.Add(i);
          }
        }
      }
     
       
      
      public class RelayCommand : ICommand
      {
        private readonly Predicate<object> _canExecute;
        private readonly Action<object> _action;
        public RelayCommand(Action<object> action, Predicate<object> canExecute) { _action = action; _canExecute = canExecute; }
        public void Execute(object o) => _action(o);
        public bool CanExecute(object o) => _canExecute == null ? true : _canExecute(o);
        public event EventHandler CanExecuteChanged
        {
          add { CommandManager.RequerySuggested += value; }
          remove { CommandManager.RequerySuggested -= value; }
        }
      }