C# xsd验证xml格式

        /// <summary>  
        /// 通过xsd验证xml格式是否正确，正确返回空字符串，错误返回提示  
        /// </summary>  
        /// <param name="xmlFile">xml文件</param>  
        /// <param name="xsdFile">xsd文件</param>  
        /// <param name="namespaceUrl">命名空间，无则默认为null</param>  
        /// <returns></returns>  
        public string XmlValidationByXsd(string xmlFile, string xsdFile, string namespaceUrl = null)
        {
            StringBuilder sb = new StringBuilder();
            XmlReaderSettings settings = new XmlReaderSettings();
            settings.ValidationType = ValidationType.Schema;
            settings.Schemas.Add(namespaceUrl, xsdFile);
            settings.ValidationEventHandler += (x, y) =>
            {
                sb.AppendFormat("{0}", y.Message);
            };
            using (XmlReader reader = XmlReader.Create(xmlFile, settings))
            {
                try
                {
                    while (reader.Read()) ;
                }
                catch (XmlException ex)
                {
                    sb.AppendFormat("{0}", ex.Message);
                }
            }
            return sb.ToString();
        }