private void NeedWords()
 {
     if (_words == null)
     {
         Error_Control_Block ecb = new Error_Control_Block();
         int wordCount           = GetWordCount();
         _words = new IGR_Page_Word[wordCount];
         if (wordCount > 0)
         {
             Check(ISYS11df.IGR_Get_Page_Words(_pageHandle, 0, ref wordCount, _words, ref ecb), ecb);
         }
     }
 }