help me

i want to load file bitmap:
event Button Open:
void CDrawing2BitmapDlg::OnBnClickedBopen()
{
      
      
      // TODO: Add your control notification handler code here
      //xay dung bo loc cho open dialog
      static char BASED_CODE szFilter[]= "Bitmap File (*.Bmp)|*.bmp||";
      //tao hop hoi thoai open
      CFileDialog m_ldFile (TRUE,".bmp",m_sBitmap,OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,szFilter);
      //xem hop hoai thoi va lay ket qua
      if (m_ldFile.DoModal()==IDOK)
      {
            //lay ten file duoc chon
            m_sBitmap=m_ldFile.GetPathName();
            //tai file bitmap vao bo nho
            //lay handle cua bitmap
            HBITMAP hBitmap =(HBITMAP)::LoadImage(AfxGetInstanceHandle(),m_sBitmap,IMAGE_BITMAP,0,0,LR_LOADFROMFILE|LR_CREATEDIBSECTION);
            //ta da co gia tri handle cua bitmap
            //kiem tra cac dieu kien cua handle
            if (hBitmap)//neu chung ta da co handle
            {
                              //xoa anh bitmap hien thoi dang luu
                  if(m_bmpBitmap.DeleteObject());
                  //neu co mot anh thi hay go no ra
                  m_bmpBitmap.Detach();
                  //gang anh muon xem vao Bitmap Object
                  m_bmpBitmap.Attach(hBitmap);
                  //vo hieu hoa control Image
            }
            
      }
}
function showbitmap:
void CDrawing2BitmapDlg::ShowBitmap(CPaintDC* pdc,CWnd *pWnd)
{

      CDrawing2BitmapDlg *lpWnd=(CDrawing2BitmapDlg*)pWnd;
      BITMAP bm;
      //lay bitmap da load
      lpWnd->m_bmpBitmap.GetBitmap(&bm);
      CDC dcMem;
      // tao device context de load bitmap vao
      dcMem.CreateCompatibleDC(pdc);
      CBitmap *pOldBitmap=(CBitmap*)dcMem.SelectObject(lpWnd->m_bmpBitmap);
      CRect lRect;
      GetClientRect(lRect);
      lRect.NormalizeRect();
      pdc->StretchBlt(10,10,(lRect.Width()-20),(lRect.Height()-20),&dcMem,0,0,bm.bmWidth,bm.bmHeight,SRCCOPY);
      dcMem.SelectObject(pOldBitmap);
      
}
 and in Onpaint:
void CDrawing2BitmapDlg::OnPaint()
{
      if (IsIconic())
      {
            CPaintDC dc(this); // device context for painting

            SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

            // Center icon in client rectangle
            int cxIcon = GetSystemMetrics(SM_CXICON);
            int cyIcon = GetSystemMetrics(SM_CYICON);
            CRect rect;
            GetClientRect(&rect);
            int x = (rect.Width() - cxIcon + 1) / 2;
            int y = (rect.Height() - cyIcon + 1) / 2;

            // Draw the icon
            dc.DrawIcon(x, y, m_hIcon);
      }
      else

      {
            CPaintDC dc(this);
            CDrawing2BitmapDlg* pWnd=(CDrawing2BitmapDlg*)GetParent();
            if(pWnd)
            {
            ShowBitmap(&dc,pWnd);
            CDialog::OnPaint();
            //Draw();
            }
      }
            
}
 

i don't know wrong anywhere , i can't load bitmap
if you have a source about MFC , program can load, draw on bitmap loaded and save that bimap, thank you