Setting filter fails on freshly opened Objectdataset when user defined Fields are used

If you use an Objectdataset and set user defined fields and the sort property immidiately on creation, the field
fProperties: IList<TRttiProperty>;
is not initialized and therefore the sort property is not set.

Solution: Add Check and initialization in procedure InternalSetSort.

Code demonstrating the problem:

type
  TPerson = class
  private
    FVorname: string;
    FNachname: String;
  published
    constructor Create (aVorname, aNachname:string);
    property Vorname: string read FVorname write FVorname;
    property Nachname: String read FNachname write FNachname;
  end;

  TForm12 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form12: TForm12;

implementation

{$R *.dfm}

procedure TForm12.FormCreate(Sender: TObject);
var
  Objectdataset: TObjectDataset;
  LStrField: TStringField;
  LIntField: TIntegerField;
  personlist: IList<TPerson>;
begin
  personlist:=TCollections.CreateList<TPerson>;
  personlist.Add(TPerson.Create('a','wolf'));
  personlist.Add(TPerson.Create('a','meier'));

  Objectdataset:= TObjectDataset.Create(self);
  Objectdataset.DataList:=personlist as IObjectlist;

  LStrField := TWideStringField.Create(Objectdataset);
  LStrField.FieldName := 'Vorname';
  LStrField.DataSet := Objectdataset;

  LStrField := TWideStringField.Create(Objectdataset);
  LStrField.FieldName := 'Nachname';
  LStrField.DataSet := Objectdataset;

  Objectdataset.Open;
  Objectdataset.Sort:='Nachname';

  if not Objectdataset.Sorted then
    raise Exception.Create('Not sorted');  // Here Dataset is not sorted

end;

{ TPerson }

constructor TPerson.Create(aVorname, aNachname: string);
begin
  FVorname:=aVorname;
  FNachname:=aNachname;
end;

My solution proposal:

‌

procedure TObjectDataSet.InternalSetSort(const value: string; index: Integer);
var
  pos: Integer;
  ownership: ICollectionOwnership;
  ownsObjects: Boolean;
  changed: Boolean;
begin
  if IsEmpty then
    Exit;

  DoBeforeSort;

  if not fProperties.Any then  // <--- check if properties exist
    InitRttiPropertiesFromItemType(fItemTypeInfo);  <---  otherwise initialize 

  changed := value <> fSort;
  fIndexFields := CreateIndexList(value);
  fSorted := Length(fIndexFields) > 0;
  fSort := value;

‌

Comments (2)