Antonio,
If I'm understanding what you want to do, I think you have misunderstood what Tim has proposed, which is what I would do as well.

You would use the Validated() method of each of the two fields that affect the third field. Any time the user changes either of the fields used in the calculation of the third, you would recalculate the value of the third field. I would put the recalculation code in a separate method that is called by each of the fields involved in the recalculation. Show the 3rd field in a readonly textbox. You could also add double-click code to the readonly textbox that would also fire the recalculation code.



>Hi Tim,
>
>Thanks for your early response.
>
>The problem that I have is that the user needs to see the result in the form and allow them to change this result with a doubleclick, so it cannot be validated, it is one a suggested value.
>
>My question was about the posibility of using the PropertyChanged event to do this.
>
>Best Regards,
>Antonio Llano