面板中获取所有是TdxDBTreeList的,如何撰写通用的时间,并调用?

在 Focus_TreeList:=(PageControl_Tree.ActivePage.Controls[i] as TdxDBTreeList);获取所有的控件是TdxDBTreeList,转化为Focus_TreeList后,
我撰写Focus_TreeListCustomDrawCell了事件,但是所有转化后的TdxDBTreeList控件,不能获取这个事件?
  怎样才能让所有的TdxDBTreeList控件调用这个事件!(我要让所有的TdxDBTreeList控件自动填充设置好的颜色和字体),
  谢谢!
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function Tform_main.getFocusTreeList: boolean;
var
    i:integer;
begin
  result:=false;
  if PageControl_Tree.ActivePage=nil then exit;
  for i:=PageControl_Tree.ActivePage.ControlCount-1 downto 0 do
    if (PageControl_Tree.ActivePage.Controls[i] is TdxDBTreeList) and
        PageControl_Tree.ActivePage.Controls[i].Visible then
    begin
        Focus_TreeList:=(PageControl_Tree.ActivePage.Controls[i] as TdxDBTreeList);
        io_mydxdbTreelist:=Focus_TreeList;
        result:=true;
        try
          //这里读取GRID颜色设置、分组设置
          LoadTreeViewSeting(io_mydxdbTreelist,go_user.user_sid,'');
        except
          application.MessageBox('读取视图设置出错','PowerOn',mb_ok);
          exit;
        end;
        break;
    end;
end;