private void Push(XmlQualifiedName elementName) {
context = (ValidationState)validationStack.Push();
if (context == null) {
context = new ValidationState();
validationStack.AddToTop(context);
}
context.LocalName = elementName.Name;
context.Namespace = elementName.Namespace;
context.HasMatched = false;
context.IsNill = false;
context.NeedValidateChildren = false;
}