procedure TForm1.Button1Click(Sender: TObject);
var
  aFormClass : TPersistentClass;
  fakeForm : TForm;
  isHaveToCreate : Boolean;
  sFormClassName,sFormName : String;
  i, j: Integer;
begin
  sFormClassName := Edit1.Text;  //<-Edit1 輸入要開啟的 FormClassName ex:TForm2      aFormClass := GetClass(sFormClassName);
  if Assigned(aFormClass) then
  begin
      isHaveToCreate := True;
      j := -1;
      sFormName := Copy(sFormClassName, 2, Length(sFormClassName) - 1);
      //檢查是否已開啟
      for i := 0 to Screen.FormCount - 1 do
        if Screen.Forms[i].Name = sFormName then
        begin
          isHaveToCreate := False;
          j := i;
          break;
        end;
      //Form 的處理
      if isHaveToCreate then
      begin //建立新的From
        if aFormClass.ClassParent = TForm then
        begin
          Application.createForm(TComponentClass(aFormClass), fakeForm);
          fakeForm.Show;
        end
      end
      else if j > -1 then
        Screen.Forms[j].Show;
  end
  else ShowMessage(sFormClassName   ' not RegisterClass!!');
end;    ------------------------------------
另外在其他被開啟的 Form 中最後加入如下簡單兩行程式碼:    initialization                   //*
  RegisterClass(TForm2);         //*
end.