每次我尝试使用XMLDocument.DocumentElement;访问文档的根目录时，以下代码都会引发“InvalidPointer”异常。beginXMLDocument:=TXMLDocument.Create(nil);//nilsincewedon'tneedanownerAStream:=TStream.Create;//streamforoutputasstringXMLDocument.loadFromXML(xml);//loadstringifNOT(XMLDocument.IsEmptyDoc)thenbeginXMLDocument.Active:=true;