在Delphi表单上递归更新字体

Question

我正在尝试迭代窗体上的所有控件并启用ClearType字体平滑.像这样的东西:

procedure TForm4.UpdateControls(AParent: TWinControl);
var
  I: Integer;
  ACtrl: TControl;
  tagLOGFONT: TLogFont;
begin
  for I := 0 to AParent.ControlCount-1 do
  begin
    ACtrl:= AParent.Controls[I];

    // if ParentFont=False, update the font here...

    if ACtrl is TWinControl then
      UpdateControls(Ctrl as TWinControl);
  end;
end;

现在,有没有一种简单的方法来检查是否ACtrl有一个Font属性,所以我可以传递Font.Handle给一些思考,如:

GetObject(ACtrl.Font.Handle, SizeOf(TLogFont), @tagLOGFONT);
tagLOGFONT.lfQuality := 5;
ACtrl.Font.Handle := CreateFontIndirect(tagLOGFONT);

先感谢您.

Answer 1

您使用TypInfo单元,更具体地说是方法IsPublishedProp和GetOrdProp.

在你的情况下,它将是这样的:

if IsPublishedProp(ACtrl, 'Font') then
  ModifyFont(TFont(GetOrdProp(ACtrl, 'Font')))

来自我的一个库的片段应该让您走上正确的道路:

function ContainsNonemptyControl(controlParent: TWinControl;
  const requiredControlNamePrefix: string;
  const ignoreControls: string = ''): boolean;
var
  child   : TControl;
  iControl: integer;
  ignored : TStringList;
  obj     : TObject;
begin
  Result := true;
  if ignoreControls = '' then
    ignored := nil
  else begin
    ignored := TStringList.Create;
    ignored.Text := ignoreControls;
  end;
  try
    for iControl := 0 to controlParent.ControlCount-1 do begin
      child := controlParent.Controls[iControl];
      if (requiredControlNamePrefix = '') or
         SameText(requiredControlNamePrefix, Copy(child.Name, 1,
           Length(requiredControlNamePrefix))) then
      if (not assigned(ignored)) or (ignored.IndexOf(child.Name) < 0) then
      if IsPublishedProp(child, 'Text') and (GetStrProp(child, 'Text') <> '') then
        Exit
      else if IsPublishedProp(child, 'Lines') then begin
        obj := TObject(cardinal(GetOrdProp(child, 'Lines')));
        if (obj is TStrings) and (Unwrap(TStrings(obj).Text, child) <> '') then
          Exit;
      end;
    end; //for iControl
  finally FreeAndNil(ignored); end;
  Result := false;
end; { ContainsNonemptyControl }

Answer 2

没有必要使用RTTI.每个TControl后代都有一个Font属性.在TControl级别,其可见性受到保护,但您可以使用此变通方法来访问它:

type
  THackControl = class(TControl);

ModifyFont(THackControl(AParent.Controls[I]).Font);