WPARAM与LPARAM的区别

*在对话框中取出数据，并向其他窗口发送消息和数据，将数据指针作为一个参数发送 * /
void CTestDlg2: :OnCommBtn ( )
{
      char szOut [30 ] ;
      GetDlgItemText (IDC_OUT ,szOut ,30 ) ;
      m_pParent - >SendMessage (WM_DLG_NOTIFY , (WPARAM )szOut ) ;
}
/*在消息接收窗口中*/
/*映射消息处理函数*/
ON_MESSAGE (WM_DLG_NOTIFY ,OnDlgNotifyMsg )
/*在视图中绘制出字符串 m_szOut*/
void CMy53_s1View : :OnDraw (CDC * pDC )
{
      CMy53_s1Doc * pDoc = GetDocument ( ) ;
      ASSERT_VALID (pDoc ) ;
      // TODO: add draw code for native data here
      pDC - >TextOut (0 ,0 , "Display String" ) ;
      pDC - >TextOut (0 ,20 ,m_szOut ) ;
}
/*处理通知消息，保存信息并更新显示*/
LONG CMy53_s1View : :OnDlgNotifyMsg (WPARAM wP ,LPARAM lP )
{
      m_szOut = ( char * )wP ;
      Invalidate ( ) ;
      return 0 ;
}