MdiChild子窗体中如何调用 Mdi主窗体中的 AdoConnection

Question

MdiChild 封装在Dll中,子窗体中有AdoQuery控件,
Dll 工程文件中的函数为:function ShowChild(App:TApplication;PFormFreeCallBack:Pointer):TForm;stdcall; export;
begin
  Application:=App;
  Result:=TDll_Frm.Create(Application);
  @FormFreeCallBack:=PFormFreeCallBack;
end; 主窗体的调用为:
ChildForm:=ShowChild(Application,@FormFreeCallBack);怎样在子窗体中可以调用主窗体中的AdoConnection?如:
function ShowChild(App:TApplication;PFormFreeCallBack:Pointer;ado:TadoConnection):TForm;stdcall; export;
begin
  Application:=App;
  Result:=TDll_Frm.Create(Application);
  @FormFreeCallBack:=PFormFreeCallBack;
end;ChildForm:=ShowChild(Application,@FormFreeCallBack,AdoConnection1);但结果不行.

Answer 1

create adoconnection to dm

Answer 2

Dll 工程文件中的uses ADODB.