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Problem with initial value of property
Message
De
28/09/2012 19:26:08
 
 
À
28/09/2012 19:16:45
Information générale
Forum:
Visual FoxPro
Catégorie:
Classes - VCX
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows XP SP2
Database:
Visual FoxPro
Divers
Thread ID:
01553671
Message ID:
01553909
Vues:
58
You wrote: It cannot possibly be by design, as it has nowhere been documented.

I disagree with your assertion. Simply because something is not documented does not mean it is not a result of the design. Some features
are only "documented" by word of mouth, which is how Iearned of this, long ago, here in the UT.



>Hi Doug,
>
>Your Nope is simply incorrect. It cannot possibly be by design, as it has nowhere been documented.
>
>The reason you mention is far sought, as it would have been only a simple extra piece of code to re-initialize the properties, without almost any impact on the performance.
>
>I am also almost sure that this flaw is not occurring in scx's.
>
>>Hi Peter.
>>
>>>'By-design' may be what has been told to you, but to me that sounds like a rationalisation, to hide the real reason: a design flaw or simply a blind spot for this when implementing it, in both cases a flaw they somehow didn't want to repair.
>>
>>Nope, Jim is right -- it's by design, and has been there since VFP 3.0. The reason is the way VFP handles classes: a class is a template for an object. As Jim notes, when you instantiate a class for the first time, the class is read into memory and any properties with "=" are evaluated. VFP then copies the class definition to create the object. Instantiating it again creates another copy, but with the same property values as the class. So, properties with "=" are evaluated for the first object only.
>>
>>(Thanks to Christof Wollenhaupt for explaining this to me.)
>>
>>Doug
Jim Nelson
Newbury Park, CA
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