delphi - TComboBox 'Control has no parent window' in destructor -

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i'm using delphi xe2. build custom tcombobox can add key/string pairs , handle cleanup in component's destructor.

all if not (csdesigning in componentstate) code omitted brevity.

interface  type   tkeyrec = class(tobject)     key: string;     value: string;   end;    tmycombobox = class(tcombobox)   public     destructor destroy; override;     procedure additempair(const key, value: string);   end;  implementation  destructor tmycombobox.destroy; var i: integer; begin   := 0 self.items.count - 1     self.items.objects[i].free;   self.clear;   inherited; end;  procedure tmycombobox.additempair(const key, value: string); var rec: tkeyrec; begin   rec := tkeyrec.create;   rec.key := key;   rec.value := value;   self.items.addobject(value, rec); end;

when application closes, destructor called, items.count property inaccessible because tcombobox must have parent control access property. time destructor called, no longer has parent control.

i saw problem once before , had store objects in separate tlist , free them separately. worked because order added them tlist same strings added combo box. when user selected string, use combo box index find correlating object in tlist. if combo box sorted, indexes won't match, can't use solution.

has else seen this? how did workaround issue? nice able free objects in component's destructor!

you can override function getitemsclass:

function getitemsclass: tcustomcomboboxstringsclass; override;

it called combo create items (by default tcomboboxstrings probably). can create own tcomboboxstrings descendant, example tcomboboxstringobjects, can free object linked item (when item deleted).


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