[DUG] Compnent creation question

[Robert martin]

(Resend didn't seem to come through last time)

Hi

Thanks Kyley.

I actually managed to get that somewhat working but picked up a number
of other issues.  for now I have given up and just overridden the clear
procedure to free the items.  Not great but for my purposes adequate.


Thanks to all for suggestions and comments.
Rob


Kyley Harris wrote:
> Override:
>     function GetItemsClass: TCustomComboBoxStringsClass; virtual; 
> abstract;
> Create your own subclass of TCustomComboBoxStrings and override the 
> Item add and Item delete routines. You need to place a synched copy of 
> your objects into a seperate list so that when the windows handle to 
> the combobox is released or recreated you don't loose your object 
> pointers. you can also add asserts or tests on the combobox.handle 
> rather than letting it crash all the time. then on the destroy of your 
> TCustomCombobox strings free all the objects in the list.. This would 
> be easiest by using a TObjectList with owns objects = true.
>
>
>  
> On Wed, Oct 15, 2008 at 4:22 PM, Robert martin <rob at chreos.co.nz 
> <mailto:rob at chreos.co.nz>> wrote:
>
>     Hi
>
>     Just trying to make a TComboBox that automatically frees its items.
>
>     I have the following code in the destructor
>
>        if (fAutomaticallyFreeObjects = True)
>                and ((csDesigning in ComponentState) = False) then begin
>            try
>                for Counter := 0 to Self.Items.Count - 1 do begin
>                    O := Items.Objects[Counter];
>                    if (O <> nil) then begin
>                       O.Free;
>                    end;
>                end;
>            except
>                on e: exception do begin
>                    ShowMessage(IntToStr(i) + ' ' + 'Attempting to
>     automatically free object memory.  The following error occured...' +
>     #13#13 + e.message);
>                end;
>            end;
>        end;
>
>
>     I get a 'Control '' has no parent error.  This happens when attempting
>     to access the .Items property.  My custom error handling does not
>     trigger.
>
>     Any suggestions ?
>
>     Thanks
>     Rob
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>
>
> -- 
> Kyley Harris
> Harris Software
> +64-21-671-821
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