On Dec 23, 2006, at 6:35 AM, Tom Benson wrote:
On 23/12/2006, at 9:47 AM, Tom Benson wrote:
Woudn't you need to cast it as a MyEditField (rather than a
vanilla Editfield) in order to trigger a custom method..
ie.
if app.LayoutPraticiens.Control(i) isa MyEditField then
MyEditField(app.LayoutPraticiens.Control(i)).raz
If the method is, as seems the case here, a method of MyEditField
then yes and there will be a compiler error to tell you that raz
is not a method of EditField.
The other two possibilities:
1) the method is in EditField and then a polymorphic override
exists with a copy in MyEditField. In that case, despatching via
the parent class will be legal and the normal virtual method
resolution will take place. (In C++ terms, you are casting a
pointer to point to the parent class.)
Are you sure Andy? I would have thought that
a) if you'd overridden an Editfield method, and
b) then cast a control in a loop like this as an Editfield and not
as a MyEditfield
then the result would be a call to the Editfield function, and not
the MyEditfield function...
He's right.
In fact I rely on this heavily in a number of my projects (being
able to call a superclasses method that I have overridden by
casting the object as it's superclass)
The correct way to do this is to call such a method using Super --
Super.Foo.
Charles Yeomans
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