Hi Stefan,

Thanks for your answer. I've taken a look at the links, but they don't provide a clear answer. Let me describe my context better:

Suppose I have a class which contains only a Value property:

public class ItemValue

{

  public decimal Value {get;set;}

}

and a view model class:

public class ViewModel

{

 public ItemValue A {get;set;}

 public ItemValue B {get;set;}

 public ItemValue Result {get;set;}

 private XamCalculationManager calcManager = new XamCalculationManager();

 public ViewModel()

 {

   // how do I configure calcaManager to compute A.Value + B.Value and store the result automatically in Result.Value.

  // ItemValue also implements INotifyPropertyChanged, but I left it out from the example for simplicity.

 }

}

Thanks,

Alex