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How do we check for the existence of an object?
Message
De
15/07/1999 21:51:26
 
 
À
13/07/1999 15:39:15
Information générale
Forum:
Visual FoxPro
Catégorie:
Gestionnaire d'écran & Écrans
Divers
Thread ID:
00240965
Message ID:
00242116
Vues:
30
>If a grid doesn't already exist on a form, I want to add it along the lines of:
>
>if not (object_exist())
> addobject(mygrid)
>endif
>
>how do we do it in vfp?
>
>Thanks
>
>Harry




For me, I used PemStatus() instead of Type()

I agree that Type(...) = "O" is confident sure that it is a object,
whereas PemStatus() only detect if the property, procedure, object name exist!!

e.g.
* Suppose there is a "Button Form" do as menu to show other forms..

IF !PemStatus(ThisFormSet, "FrmABC1", 5)
    Thisformset.Addobject("FrmABC1", "FrmABC")
ENDIF

Thisformset.FrmABC1.visible = .T.  && Line 5
Thisformset.FrmABC1.Zorder(1)

* At this point, the post-condition will sure Thisformset.FrmABC1 will
* show and put the top of forms order!
* If prompt error because FrmABC1 not exit at Line 5
* Use Event handlier to capture the First Destroy() just behind Init()



Sometimes, pre-condition, post-condition is very good logical method to
decision on design!! ^_~
The weak wait for chance, The strong bid for chance,
The clever notch up chance, but The merciful give you chance.
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