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RE: [platform-swt-dev] ordering problem adding buttons to a GridL ayout
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Title: Message
Thanks for the code. I'm aware of this technique, and in fact
your code gives a really good example to be discussed. Here's some
questions that illustrate the issues with imposing the lack of zero-arg
constructors for Controls:
1. In order to create the button instance, you absolutely have to
have carnal knowledge of the constructor and class you are working with.
Otherwise, you don't know which Constructor to use, or how to address
it.
2. This code makes the assumption that the final parent shell
instance is available at the time the button instance needs to be
created. This shouldn't always have to be the
case.
3. From a previous thread, it is apparent that a control cannot be
added / removed from a composite at runtime, but only associated with a single
parent via its constructor argument on creation. So rather than builder
being able to add / remove Controls from parents, they have to be continually
disposed and recreated (with all of its children).
It's worse than
that. Some things that builders like to treat as properties really are
style bits on the constructor (because that's how Windows works). So
whenever the user changes one of those "properties", you have to dispose
and recreate the control (and its
children).
But think about it:
Visual Basic, Delphi, C++ Builder, and any other Windows-based GUI builder that
manipulates Windows controls has exactly the same problem to solve. If
they can do it, we can too. (Hope to see you over at the Sweet
project.) :-)
Dave
