I fully agree that bindevent is perferct for this application, however I would not recommend binding to the interactive change as this event fires for EVERY keystroke! Rather I would use the following code:

Form::Init
* -- Use this "SET PROCEDURE" technique if using a "STANDARD" method to calculate
*------------------------------------------------------------------------------
if atc('\MySpecialCalc.',set('Procedure') = 0 && Check for "Standard" procedure 
  set procedure to MySpecialCalc additive
endif
*------------------------------------------------------------------------------
Bindevent(this.txtMyValue1,"lostfocus",this,"CalcResult",1)
Bindevent(this.txtMyValue2,"lostfocus",this,"CalcResult",1)
Bindevent(this.txtMyValue3,"lostfocus",this,"CalcResult",1)
* -- Initially calculate the result
*------------------------------------------------------------------------------
this.CalcResult()
*------------------------------------------------------------------------------

Add new method to the form and/or use a "standard" procedure to calculate the result. If this calculation is used in various places in your system it would be advisable to make a "standard" procedure.

Form::CalcResult
<pre>
with this
  .txtMyValue4.value=.txtMyValue1.value + .txtMyValue2.value + .txtMyValue3.value
endwith

Or

with this
  This.txtMyValue4.value=MySpecialCalc(.txtMyValue1.value, .txtMyValue2.value,.txtMyValue3.value)
endwith

>For this purpose, Bindevent is perfect!
>In the textbox where you want the result, I call it txtResult, you have something like this in the Refresh:

>This.value=this.parent.txtMyValue1.value + this.parent.txtMyValue2.value + this.parent.txtMyValue3.value

>Add these lines to your form, for instance in the Gotfocus method:

>Bindevent(thisform.txtMyValue1,"interactivechange",thisform.txtResult,"refresh")
>Bindevent(thisform.txtMyValue2,"interactivechange",thisform.txtResult,"refresh")
>Bindevent(thisform.txtMyValue3,"interactivechange",thisform.txtResult,"refresh")

>Then whenever you change any of the values in txtMyValue1, txtMyValue2 or txtMyValue3, txtResult will also get updated.
>
>>How do you experts implement form calculations? What I mean by this is, a form has several numeric fields and I want to make calculations based on these fields and display the results on the form, updating the results every time there is a change.
>>
>>When the form is displayed, it should calculate and display the results. When there are any changes in the numeric fields it should recalculate and display the results.
>>
>>In that I am not much of a programmer, the more specific the answer the better.
>>
>>Thanks.