CString getLine(nLine)
{
  CString strText;
  CEdit &theEdit = GetEditCtrl();
  theEdit.GetLine(nLine-1, strText.GetBuffer(theEdit.LineLength(nLine-1)));
strText.ReleaseBuffer();
  return strText;
}怎么我运行到strText.ReleaseBuffer()时就出错呢?