<i><font color="#663300">CB seems to very nicely handle multiple instances of a form, but what if I *don't* want to allow a form to have multiple instances? How do I stop it please?</font></i>
Add code to the Init() that will check for existing instances of that form class. Something like:
<code> LOCAL laInst[1]
IF AINSTANCES(laInst, This.Class) > 0
RETURN .F.
ENDIF
</code>
Since this is a function that is probably needed for many form classes, it would probably be best to add it to your a superclass for your form (such as iBaseForm). I'd then add a property named <b>lSingleton</b>, defaulting to .F., Then, any class you want to exhibit this Singleton pattern can be set by switching that property to .T. The code would then look like:
<code> LOCAL laInst[1]
IF This.lSingleton
IF AINSTANCES(laInst, This.Class) > 0
RETURN .F.
ENDIF
ENDIF
</code>
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Ed Leafe
©2002 Ed Leafe |
