引入:#import <objc/runtime.h>
if(nodePtr->type == XML_ELEMENT_NODE)
{
self->isa = [DDXMLElement class];
//object_setClass(self, [DDXMLElement class]);
}
else if(nodePtr->type == XML_DOCUMENT_NODE)
{
self->isa = [DDXMLDocument class];
//object_setClass(self, [DDXMLDocument class]);
}