Attaching CFormView to dockpane problems!

I want to attach CFormView to a dockpane,the below are the codes:

//////////////////////////////////////////////////////////// ////////////////////////////////////////

LRESULT CMainFrame::OnDockingPaneNotify(WPARAM wParam, LPARAM lParam)
{
 if (wParam == XTP_DPN_SHOWWINDOW)
  {
   // get a pointer to the docking pane being shown.
   CXTPDockingPane* pPane = (CXTPDockingPane*)lParam;
   if (!pPane->IsValid())
   {
    switch( pPane->GetID() )
    {
    case 1:
     if (m_wnd.GetSafeHwnd() == 0)
                     {
                          m_wnd.Create(WS_CHILD|ES_AUTOVSCROLL|ES_MULTILINE, CRect(0, 0, 0, 0), this, 0);         &am p;am p;nb sp;
                     }
                     pPane->Attach(&m_wnd);
                     break;
    case 2:
     {
      CFrameWnd* pFrame = new CFrameWnd;
      CCreateContext context;    
      context.m_pNewViewClass = RUNTIME_CLASS(CSetLineView);
      context.m_pCurrentDoc = GetActiveView()->GetDocument();

      pFrame->Create(NULL, NULL, WS_CHILD|WS_VISIBLE|WS_CLIPCHILDREN|WS_CLIPSIBLINGS, CRect(0, 0, 0, 0), this, NULL, 0, &context);
      pFrame->ModifyStyleEx (WS_EX_CLIENTEDGE, 0);
      pFrame->SendMessageTo Descendants(WM_INITIALUPDATE, 0, 0, TRUE, TRUE);
      pPane->Attach(pFrame) ; 
     }
     break;
    }
   }
  
   return TRUE; // handled
  }
  return FALSE;
}

//////////////////////////////////////////////////////////// //////////////////////////////////////// /////

CSetLineView inherits from CFormView,however it generates an assert!