Wie *schnell* auf Properties anhand eines String-Bezeichners zugreifen?

[Delphi.Narium]

Delphi-Quellcode:

uses
    ..., TypInfo, ...

function  HasProperty(AClass : TObject; APropertyName : String) : Boolean;
begin
  Result := Assigned(GetPropInfo(AClass.ClassInfo, APropertyName));
end;

...
  if HasProperty(ADataObj, 'ValueA') then begin
    try
      if GetStrProp(ADataObj, 'ValueA') = sName then begin
        SetStrProp(ADataObj, 'ValueA', '');
      end else
      // Analog zu Get- / SetStrProp gibt es weitere Routinen, die Du typabhängig nutzen kannst.
      ...
    except
      on e : Exception do MessageDlg(e.Message,mtErrr,[mbOk],0);
    end;
  end;
...

Daraus könnte sowas (nur hingedaddelt) werden:

Delphi-Quellcode:

function  HasProperty(AClass : TObject; APropertyName : String) : Boolean;
begin
  Result := Assigned(GetPropInfo(AClass.ClassInfo, APropertyName));
end;

procedure GetFieldValue(ADataObj: TMyDataObj; const FieldName: string): string;
begin
  if HasProperty(ADataObj, Fieldname) then result := GetStrProp(ADataObj, FieldName) else result := '?';
end;

... oder ...

procedure GetFieldValue(ADataObj: TMyDataObj; const FieldName: string): string;
begin
  Result := ifThen(HasProperty(ADataObj, Fieldname),GetStrProp(ADataObj, FieldName),'');
end;

... oder ...

procedure GetFieldValue(ADataObj: TMyDataObj; const FieldName: string): string;
begin
  Result := ifThen(Assigned(GetPropInfo(ADataObj.ClassInfo, Fieldname)),GetStrProp(ADataObj, FieldName),'');
end;