delphi dll中mdichild 自动关闭，主程序无响应？？？

Question

调用DLL中的MDICHILD窗体后，过一段时间，窗体自动关闭，主程序无响应。主程序和DLL都没带包编译。

Answer 1

var
FormHandle:hwnd;
dllapp:tapplication;
procedure LoadsysreportDLL(PApplication:TApplication;PForm: TForm;FormName:shortString;MainHandle:integer;datamodule:Tfrm_dm;pdepartment:shortstring); export; stdcall;
begin
   Application:=PApplication;
  // Screen := Scr;
   FormHandle:=MainHandle;
   frm_dm:=datamodule;
   depment:=pdepartment;
   if FormName='frm_count' then
   begin
     if not Assigned(frm_count) then
       frm_count:= Tfrm_count.Create(PForm);
   end;   if FormName='frm_order' then
   begin
     if not Assigned(frm_order) then
       frm_order:=Tfrm_order.Create(PForm);
   end;   if FormName='frm_plantp' then
   begin
     if not Assigned(frm_plantp) then
       frm_plantp:=Tfrm_plantp.Create(PForm);
   end;   if FormName='frm_time' then
   begin
     if not Assigned(frm_time) then
       frm_time:= Tfrm_time.Create(PForm);
   end;
end;
procedure  DLLUnloadProc(Reason:Integer);register;
begin
      if  (Reason=DLL_PROCESS_DETACH) or (Reason=DLL_THREAD_DETACH)   then
      begin
      if assigned(frm_count) then
      frm_count.Free;
      if assigned(frm_order) then
      frm_order.Free;
      if assigned(frm_plantp) then
      frm_plantp.Free;
      if assigned(frm_time) then
      frm_time.Free;
      Application:=DllApp;
      CoUnInitialize;
      end;
end;
exports LoadsysreportDLL;
begin
 DllApp:= Application;
 CoInitialize(nil);
 DLLProc := @DLLUnloadProc;
end.

Answer 2

DLL 中DATAMODULE是直接引用主程序中的DATAMODULE，传递frm_dm对象。