DSharp, DevExpress Editors, Bindings

[Stevie]

Delphi-Quellcode:

type
  TcxTextEdit = class(cxTextEdit.TcxTextEdit, INotifyPropertyChanged)
  private
    FNotifyPropertyChanged: TNotifyPropertyChanged;
    property NotifyPropertyChanged: TNotifyPropertyChanged
      read FNotifyPropertyChanged implements INotifyPropertyChanged;
    procedure WMChar(var Message: TWMChar); message WM_CHAR;
  protected
    procedure DoTextChanged; override;
    procedure CMExit(var Message: TCMExit); message CM_EXIT;
  public
    constructor Create(AOwner: TComponent); override;
  end;

procedure TcxTextEdit.CMExit(var Message: TCMExit);
begin
  try
    FNotifyPropertyChanged.NotifyOfPropertyChange('Text', utLostFocus);
    inherited;
  except
    on EValidationError do
    begin
      SetFocus;
    end;
  end;
end;

constructor TcxTextEdit.Create(AOwner: TComponent);
begin
  inherited;
  FNotifyPropertyChanged := TNotifyPropertyChanged.Create(Self);
end;

procedure TcxTextEdit.DoTextChanged;
begin
  inherited;
  FNotifyPropertyChanged.NotifyOfPropertyChange('Text');
end;

procedure TcxTextEdit.WMChar(var Message: TWMChar);
begin
  inherited;
  if Message.CharCode = VK_RETURN then
  begin
    FNotifyPropertyChanged.NotifyOfPropertyChange('Text', utExplicit);
  end;
end;

[mytbo]

Hallo!

Danke für den Quellcode.

Beruhigend! Eine Eins-zu-eins-Umsetzung wie in meinem Testbeispiel. Wenn sich alle DevExpress Editors so eng an ihr VCL-Pendant anlehnen und keine Fallstricke lauern, ist die Umsetzung wirklich kein Problem. Nochmals vielen Dank für DSharp.

Bis bald...
Thomas

[mytbo]

Hallo!

Noch eine Frage zur Source-Kosmetik. Spricht etwas dagegen, in der SubKlasse gleich folgendes zu schreiben:

Code:

public
  function AddBinding(pmSourceObject: TObject;
    const pmcSourcePropertyName: String; pmBindingGroup: TBindingGroup = Nil): TBinding;

function TcxTextEdit.AddBinding(pmSourceObject: TObject;
  const pmcSourcePropertyName: String; pmBindingGroup: TBindingGroup): TBinding;
begin
  Assert(pmSourceObject <> Nil);
  Assert(pmcSourcePropertyName <> '');

  if pmBindingGroup = Nil then
    pmBindingGroup := FindBindingGroup(Self.Owner);

  if pmBindingGroup <> Nil then
    Result := pmBindingGroup.AddBinding(pmSourceObject, pmcSourcePropertyName, Self, TEXTEDIT_BINDING_PROPNAME, bmTwoWay)
  else
    Result := TBinding.Create(pmSourceObject, pmcSourcePropertyName, Self, TEXTEDIT_BINDING_PROPNAME);
end;

Dann reicht im Form z.B.: edtVorname.AddBinding(SourceObject, 'Vorname');

Bis bald...
Thomas