public virtual bool CheckValidity (XmlSchemaSet schemas, ValidationEventHandler handler)
		{
			XmlReaderSettings settings = new XmlReaderSettings ();
			settings.NameTable = NameTable;
			settings.SetSchemas (schemas);
			settings.ValidationEventHandler += handler;
			settings.ValidationType = ValidationType.Schema;
			try {
				XmlReader r = XmlReader.Create (
					ReadSubtree (), settings);
				while (!r.EOF)
					r.Read ();
			} catch (XmlSchemaValidationException) {
				return false;
			}
			return true;
		}