Level Extreme platform
Subscription
Corporate profile
Products & Services
Support
Legal
Français
What's wrong with this variable?
Message
General information
Forum:
Visual FoxPro
Category:
Troubleshooting
Miscellaneous
Thread ID:
00818431
Message ID:
00818501
Views:
17
Hi Tom,
I think you hit it. When working on a collection instead of an array it works different. Have to remember that.
In my example, I was finding a match. I would trace it and see where it hit the "exit" command. It ALMOST makes sense that an object could go out of scope when leaving a for next loop but not a variable. Almost but not quite, but I'll live with it.


>Bill,
>
>Maybe its because the top example is done on a collection instead of on the array like in your second example.
>
>I am not sure in the first example if you are actually achievieng the exit from the FOR..ENDFOR because of a match or is it just dropping through when its done with no match.
>
>If it is dropping through, then it would make sense that lo would not be an object any longer because the FOR..Endfor has terminated.
>
>We have always assigned our matching object to a memory variable or a property when exiting the loop upon a sucessful match.
>
>Don't have to do it that way, but I know it works.
>
>HTH
>
>>Ok, I can deal with that. Don't understand it, but I can deal with it.
>>But how about explaining these 2 examples:
>>
>>myform.method()
>>  LOCAL lo, lc, loParent
>>  lo = 'some text'                            && locals window shows lo = 'some text'
>>  lc = WPARENT( THIS.NAME )
>>  FOR EACH lo IN _VFP.FORMS
>>    IF UPPER( lo.NAME ) == UPPER( lc )
>>      loParent = lo
>>      EXIT                                    && locals window shows lo = object
>>    ENDIF
>>  ENDFOR
>>  IF TYPE( 'loParent.NAME' ) = 'C' ;          && locals window shows lo = .F. !!!!!!!!!!!!
>>      AND loParent.WINDOWSTATE = 1
>>    loParent.WINDOWSTATE = 0
>>    loParent.REFRESH()
>>  ENDIF
>>
>>Obviously VFP is working with the local variable that I set to 'some text', it was changed from character to .F.
>>I'm guessing that means that a for each loop confiscates a variable from the method for it's own use, but doesn't restore the value back when it's done, instead it just sets it's value to .f.
>>
>>LOCAL lc, la( 5 )
>>la( 1 ) = 'A'
>>la( 2 ) = 'B'
>>la( 3 ) = 'C'
>>la( 4 ) = 'D'
>>la( 5 ) = 'E'
>>FOR EACH lc IN la
>>  IF lc = la( 3 )
>>    EXIT
>>  endif
>>ENDFOR
>>? lc                   && prints 'C' not .F.      and locals window shows lc = 'C'
>>
>>So I guess a for each loop only confiscates variables and sets them to false if I'm cycling through objects. Cycling through characters leaves it just the way I would expect.
>>
>>Is there any logic to that? or is it just a "feature" I have to live with?
>>
>>
>>
>>
>>
>>>Your FOR EACH...ENDFOR creates and uses its own copy of the lo var, not the one from your Local declaration.
>>>
>>>You have to transfer the object reference to a an actual memory variable like you have done in your second example and that is why it works.
>>>
>>>Thats also why the lo variable continures to show a .f. in the locals window.
>>>
>>>HTH,
>>>
>>>
>>>>I lost something here.
>>>>Why is it out of scope? The locals window still shows that it exists, just the wrong type(). I assume that means that it's still in scope.
>>>>
>>>>>You have gone out of scope in the FOR...ENDFOR in the first example without making a memory variable reference to the lo object being evaluated.
>>>>>
>>>>>
>>>>>>I'm using VFP 7.0
>>>>>>
>>>>>>This doesn't work
>>>>>>
>>>>>>myForm.method()
>>>>>>  LOCAL lo, lc
>>>>>>  lc = WPARENT( THIS.NAME )
>>>>>>  FOR EACH lo IN _VFP.FORMS
>>>>>>    IF lo.NAME == lc
>>>>>>      EXIT                             && Locals window shows lo as object here
>>>>>>    ENDIF
>>>>>>  ENDFOR
>>>>>>  IF TYPE( 'lo.NAME' ) = 'C' ;         && Locals window shows lo as .F. here
>>>>>>      AND lo.WINDOWSTATE = 1
>>>>>>    lo.WINDOWSTATE = 0
>>>>>>  ENDIF
>>>>>>
>>>>>>but this does
>>>>>>
>>>>>>myForm.method()
>>>>>>  LOCAL lo, lc, loParent
>>>>>>  lc = WPARENT( THIS.NAME )
>>>>>>  FOR EACH lo IN _VFP.FORMS
>>>>>>    IF lo.NAME == lc
>>>>>>      loParent = lo
>>>>>>      EXIT                             && Locals window shows lo as object here
>>>>>>    ENDIF
>>>>>>  ENDFOR
>>>>>>  IF TYPE( 'loParent.NAME' ) = 'C' ;   && Locals window shows lo as .F. here
>>>>>>      AND loParent.WINDOWSTATE = 1
>>>>>>    loParent.WINDOWSTATE = 0
>>>>>>  ENDIF
>>>>>>
Bill Morris
Previous
Next
Reply
Map
View

Click here to load this message in the networking platform