As mentioned above form1 should provide a predicate that can return the text:
interface form1 supports formThat is the simple part, the difficult part is how form2 should obtain form1, because in generel there are nothing that guarenties that there is one and only one instance of a certain form.
getEditControlText : () -> string Text.
implement form1 ...
getEditControlText() = editControl_ctl:getText().
end implement form1.
Your program may of course have some special properties that ensures that there is exactly one form1 open. But it will require that form1 cannot be closed, and that additional form1's cannot be opened.
In that case it seems relatively safe to assert the form in a class fact somewhere so that form2 can access it through that fact.