How to update TextBox Control on Subform ?

selece28

Hi Nav Masters,
I have created a Header Details form like in Sales Order.
Then when i change one of the field in Header, i want to update the TextBox control in the Subform.
For information, the TextBox in subform is like the "Availability ()" in the Item Information Pane. It Call a function to calculate and return decimal.

Is there anyway to do it?
Because it seems that using : Updatecontrols and Currform.Subform.Update cannot do it.

Thanks in advance

kine

As in other cases - add new function into the subform which call CurrForm.Update or update the control in another way and call this function from the main form... ;-)