| Re: Dynamic array of an Object as class member variable. [message #45191] |
Mon, 15 August 2005 10:01 |
Karl Schultz
Messages: 341
Registered: October 1999
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Senior Member |
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On Mon, 15 Aug 2005 07:02:57 -0600, David Fanning wrote:
> Chirag Modh writes:
>
>> I want to implement dynamic array of an Object as class member
>> variable.
>>
>> ;------------------------------------------------
>> My class
>> Class= {myclass, $
>> oLine: obj_new()$
>> }
>> Function myclass :: Init , N_element
>> Self.oLine = Make_Array(N_element,/obj )
>> For i=0 , N_element do begin
>> Self.oLine[i] = obj_new('IDLgrPolyline')
>> end
>> End
>>
>> ;-----------------------------------------------------
>> I can't create dynamic array of an object as class member variable.
>> Any other way, I can implement this thing.
>
> I think if you returned a 1 from your INIT method you
> would have better luck. :-)
>
Yes, but there are other problems.
1) You can't have variable-sized things in a struct, but you can have
pointers to variable-sized things in a struct. So the member variable
needs to be a pointer.
2) The loop goes around one time too many.
Function myclass :: Init , N_element
Self.oLine = PTR_NEW(Make_Array(N_element,/obj))
For i=0 , N_element-1 do begin
(*Self.oLine)[i] = obj_new('IDLgrPolyline')
end
return, 1
End
pro myclass__define
Class= {myclass, $
oLine: ptr_new()$
}
end
Of course the Cleanup method would need to call PTR_FREE to free oLine and
you would need to think about when and how to destroy the polyline objects
themselves.
Karl
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| Re: Dynamic array of an Object as class member variable. [message #45194 is a reply to message #45191] |
Mon, 15 August 2005 06:02  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Chirag Modh writes:
> I want to implement dynamic array of an Object as class member
> variable.
>
> ;------------------------------------------------
> My class
> Class= {myclass, $
> oLine: obj_new()$
> }
> Function myclass :: Init , N_element
> Self.oLine = Make_Array(N_element,/obj )
> For i=0 , N_element do begin
> Self.oLine[i] = obj_new('IDLgrPolyline')
> end
> End
>
> ;-----------------------------------------------------
> I can't create dynamic array of an object as class member variable.
> Any other way, I can implement this thing.
I think if you returned a 1 from your INIT method you
would have better luck. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
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