Abgel. graf. Komponente aktualisiert nicht

[jfheins]

Also, so funktioniert es:

Delphi-Quellcode:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
   end;

   TKlasse = class(TGraphicControl)
   public
      procedure DoSomething;
   end;

   TErbe1 = class(TKlasse)
   protected
      procedure Paint; override;
   end;

   TErbe2 = class(TKlasse)
   protected
      procedure Paint; override;
   end;


var
   Form1: TForm1;
   Klasse: TKlasse;

implementation

{$R *.dfm}

{ TKlasse }

procedure TKlasse.DoSomething;
begin
   Paint;
end;

{ TErbe1 }

procedure TErbe1.Paint;
begin
  inherited;

   with Canvas do
   begin
      Brush.Color := clRed;
      Rectangle(10, 10, 80, 80);
   end;

end;

{ TErbe2 }

procedure TErbe2.Paint;
begin
  inherited;

   with Canvas do
   begin
      Brush.Color := clGreen;
      Ellipse(10, 10, 80, 80);
   end;

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 Klasse := TErbe1.Create(Self);

   with Klasse do
   begin
      Parent := Self;
      Top := 50;
      Left := 50;
      Height := 100;
      Width := 100;
   end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
Klasse.DoSomething;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
   Klasse.Free;
end;

end.