how to autofill a field in subform based on main form

[sami1900]

I have a field which I want make it takes its value from the main form. For example, I have a field in main form [Saled Quantity] and the same field in subform and I entered 1000 in the main form as value, I want this value shows in the subform directly.

same Value with one entry in each form

many Thanks

[ranman256]

use the builder to get the path and object names correct....

sub Saled_Quantity_afterupdate()
  me.subormName.form.txtBox = me.Saled_Quantity
end sub

[sami1900]

but when no names here for main form I mean I didn't find the field which I will take the value from it, all things here from subform.