既然我们已经了解了AddCategories方法，现在就让我们来看看AddCategories方法所用到的助手方法。首先，我们看看ValidateXML方法。像前面所提到的那样，该方法负责确保被添加的CategoriesXML数据遵从Categories.xsd中所预先定义好的XML模式。

privateboolValidateXml(stringxml)

{

boolvalidXml=false;

//LoadtheXMLdataintomemory

XmlValidatingReadervalReader=new

XmlValidatingReader(xml,XmlNodeType.Document,null);

valReader.Schemas.Add(null,Server.MapPath("Categories.xsd"));

valReader.ValidationType=ValidationType.Schema;

valReader.ValidationEventHandler+=new

ValidationEventHandler(ValidationHandler);

//LoopthroughtheXMLfile

while(valReader.Read())

{}

if(builder.Length>0)

validXml=false;

else

validXml=true;

valReader.Close();

returnvalidXml;

}