[DUG] Compnent creation question

[Kyley Harris]

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> 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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