title: WPF mvvm property in viewmodel without setter?
body: <p>I'm dealing with some WPF problems using and sticking to the MVVM pattern.</p>
  
  <p>Most of my properties look like this:</p>
  
  <pre><code>public string Period
  {
      get { return _primaryModel.Period; }
      set
      {
          if (_primaryModel.Period != value)
          {
              _primaryModel.Period = value;
              RaisePropertyChanged("Period");
          }
      }
  }
  </code></pre>
  
  <p>This works excellent.</p>
  
  <p>However I also have some properties like this:</p>
  
  <pre><code>public bool EnableConsignor
  {
      get
      {
          return (ConsignorViewModel.Id != 0);
      }
  }
  </code></pre>
  
  <p>It doesn't have a setter as the id is changed "automatically" (every time the save of <code>ConsignorViewModel</code> is called. However this leads to the problem that the "system" doesn't know when the bool changes from false to true (as no <code>RaisePropertyChanged</code> is called).</p>