title: WPF binding with where clause possible?
body: <p>If I had an <code>Observable</code> collection like so :</p>
  
  <pre><code>public ObservableCollection&lt;SpecialPriceRow&gt; SpecialPriceRows = new ObservableCollection&lt;SpecialPriceRow&gt;();
  </code></pre>
  
  <p><code>SpecialPriceRow</code> class :</p>
  
  <pre><code>public class SpecialPriceRow : INotifyPropertyChanged
  {
      public enum ChangeStatus
      {
          Original,
          Added,
          ToDelete,
          Edited
      }
  
      public ChangeStatus Status { get; set; }
      public string PartNo { get; set; }
  
      private decimal _price;
      public decimal Price
      {
          get
          {
              return _price;
          }
          set
          {
              if (value != _price)
              {
                  _price = value;
                  Status = ChangeStatus.Edited;
                  OnPropertyChanged("Status");
              }
          }
      }
  
      public event PropertyChangedEventHandler PropertyChanged;
      private void OnPropertyChanged(string name)
      {
          PropertyChangedEventHandler handler = PropertyChanged;
          if (handler != null)
          {
              handler(this, new PropertyChangedEventArgs(name));
          }
      }
  }
  </code></pre>
  
  <p>Would it be possible for me to bind a Label in the XAML to the count of objects that are say ... Added? So I could get something like this :</p>
  
  <p><img src="https://i.stack.imgur.com/uIAp4.png" alt="enter image description here"></p>
  
  <p>Where green is the count of "Added" objects within the collection. How would I go about doing something like this?</p>