In fact, the GTK object has to be created whenever the fComponent is addressed, which is…
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-----Original Message-----
From: Michal Bukovjan
Sent: 16 August 1999 08:13 PM
To:
Subject: Re: [[lazarus] CreateComponent]
In fact, the GTK object has to be created whenever the fComponent is
addressed, which is in most messages that exist now.
In that case people should not refer to .fComponent, but .Handle (whose getter calls HandleNeeded which actually creates the control. I have actually implemented all this in my copy and will be ready for checking in soon by someone).
One solution would be to make Component property and GetComponent it's read method, which would create the component on demand, or have a method like ComponentNeeded.
As you say. Delphi does this in handleneeded.
The Windows way (of creating controls), however, is VERY different, which might be a problem.
They are different but it isn't actually a problem. I once wrapped some C graphing tools (Quinn Curtis - pretty nasty I thought) as Delphi controls and they were like this, but it worked OK.
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In a Windows control (which is not OO), you
supply nearly
all controls' properties at CreateWindow(Ex), and whenever you
want to change
a property, you call RecreateWnd. (the rest goes through messages).
But in the end it doesn't matter if the visible properties (caption etc) are set via messages or psuedo-properties.
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In GTK, the components are much like Delphi ones, i.e. they have a sort of
pseudo-properties that can be changed through various functions
(they are not
classes or objects to preserve C compatibility, but if you look
closely, they
are VERY much like them. In fact, I think they were converted
from what once
was a C++ code), without the need (and in fact there is no such thing) to
recreate control. Yes, you can destroy and then create the
control once again,
then setup all properties, but this is a DRAG.
Its not really a drag, its fully "automatic". There is no problem with it at all.
Sam