Typumwandlung: Elemente der Unterklasse in Oberklasse

[Blup]

Versuch es mit einer virtuellen Testmethode.

Delphi-Quellcode:

TOberklasse = class(TObject)
protected
  function TestMethode: string; virtual;
public
  class procedure Test(AObj: TOberklasse);
  constructor Create;
end;

TUnterklasse = class(TOberklasse)
protected
  function TestMethode: string; override;
public
  Name: String;
  constructor Create;
end;

implementation

class procedure TOberklasse.Test(AObj: TOberklasse);
begin
  if Assigned(AObj) then
    ShowMessage(AObj.TestMethode);
end;

procedure TOberklasse.TestMethode;
begin
  Result := 'ClassName = ' + ClassName;
end;

procedure TUnterklasse.TestMethode;
const
  CRLF = #13#10;
begin
  Result :=
    inherited TestMethode + CRLF +
    'Name = ' + Name;
end;