problem bei einer Komponentenentwicklung

[bergamo34]

habe Probleme beim Erstellen einer neuen Komponente aus TEdit und TDBGrid.

Es kommt folgende Fehlermeldung wenn Spalten für die SubKomponente 'GridList' eingestellt sind.

Fehlermeldung:
..EReadError...'Eigenschaft GridList existiert nicht'.

kann jemand mir sagen, wo ich den Fehler mache?

Code:

unit EditLookList;

interface

uses
  Windows, Controls, SysUtils, Classes, StdCtrls, DBGrids, DBCtrls,
  Messages, Forms, Menus, Graphics;

type
{-- TBoundGrid -----------}
  TBoundGrid = class(TDBGrid)
  private
    { Private-Deklarationen }
  protected
    { Protected-Deklarationen }
  public
    constructor Create(AOwner: TComponent); override;
    { Public-Deklarationen }
  published
    { Published-Deklarationen }
    property Options;
  end;

  TGridPosition = (lpAbove, lpBelow, lpLeft, lpRight);

{-- TCustomEditList -----------}
  TCustomEditList = class(TEdit)
  private
    FGrid: TBoundGrid;
    FGridPosition: TGridPosition;
    FGridSpacing: Integer;

    procedure SetGridPosition(const Value: TGridPosition);
    procedure SetGridSpacing(const Value: Integer);
    { Private-Deklarationen }
  protected
    procedure SetParent(AParent: TWinControl); override;
    procedure Notification(AComponent: TComponent; Operation: TOperation); override;
    procedure CMEnter(var Message: TCMEnter); message CM_ENTER;
    procedure CMExit(var Message: TCMExit); message CM_EXIT;
    { Protected-Deklarationen }
  public
    constructor Create(AOwner: TComponent); override;
    procedure SetBounds(ALeft: Integer; ATop: Integer; AWidth: Integer; AHeight: Integer); override;
    procedure SetupInternalGrid;
    property Grid: TBoundGrid read FGrid;
    { Public-Deklarationen }
  published
    property GridPosition: TGridPosition read FGridPosition write SetGridPosition;
    property GridSpacing: Integer read FGridSpacing write SetGridSpacing;
    { Published-Deklarationen }
  end;


  TEditLookList = class(TCustomEditList)
  private
    { Private-Deklarationen }
  protected
    { Protected-Deklarationen }
  public
    { Public-Deklarationen }
  published
    property GridPosition default lpAbove;
    property GridSpacing default 3;
    property Grid;
    { Published-Deklarationen }
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Beispiele', [TEditLookList]);
end;

{ TBoundGrid }

constructor TBoundGrid.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Name := 'SubGrid';  { do not localize }
  SetSubComponent(True);
  if Assigned(AOwner) then
    Caption := AOwner.Name;

end;


{ TCustomEditList }

procedure TCustomEditList.CMEnter(var Message: TCMEnter);
begin
  inherited;
  if not FGrid.Visible then
    FGrid.Visible := True;

end;

procedure TCustomEditList.CMExit(var Message: TCMExit);
begin
  inherited;
//  if FGrid.Visible then
//    FGrid.Visible := False;
    
end;

constructor TCustomEditList.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FGridPosition := lpBelow;
  FGridSpacing := 3;
  SetupInternalGrid;

end;

procedure TCustomEditList.Notification(AComponent: TComponent;
  Operation: TOperation);
begin
  inherited Notification(AComponent, Operation);
  if (AComponent = FGrid) and (Operation = opRemove) then
    FGrid := nil;

end;

procedure TCustomEditList.SetBounds(ALeft, ATop, AWidth, AHeight: Integer);
begin
  inherited SetBounds(ALeft, ATop, AWidth, AHeight);
  SetGridPosition(FGridPosition);

end;

procedure TCustomEditList.SetGridPosition(const Value: TGridPosition);
var
  P: TPoint;
begin
  if FGrid = nil then exit;
  FGridPosition := Value;
  case Value of
    lpAbove: P := Point(Left, Top - FGrid.Height - FGridSpacing);
    lpBelow: P := Point(Left, Top + Height + FGridSpacing);
    lpLeft : P := Point(Left - FGrid.Width - FGridSpacing,
                    Top + ((Height - FGrid.Height) div 2));
    lpRight: P := Point(Left + Width + FGridSpacing,
                    Top + ((Height - FGrid.Height) div 2));
  end;
  FGrid.SetBounds(P.x, P.y, FGrid.Width, FGrid.Height);

end;

procedure TCustomEditList.SetGridSpacing(const Value: Integer);
begin
  FGridSpacing := Value;
  SetGridPosition(FGridPosition);

end;

procedure TCustomEditList.SetParent(AParent: TWinControl);
begin
  inherited SetParent(AParent);
  if FGrid = nil then exit;
  FGrid.Parent := AParent;
  FGrid.Visible := True;

end;

procedure TCustomEditList.SetupInternalGrid;
begin
  if Assigned(FGrid) then exit;
  FGrid := TBoundGrid.Create(Self);
  FGrid.FreeNotification(Self);

end;




end.