C# 验证XML

public class XMLValidate
    { 
        /// <summary>
        /// 辅助验证变量
        /// </summary>
        private static bool isValidateXML = true;
        /// <summary>
        /// 验证提示
        /// </summary>
        private static string message; 
        /// <summary>
        /// 验证上传的XML文件是否是格式正确的
        /// </summary>
        /// <param name="filename">XML文件路径</param>
        /// <param name="schema">XSD文件路径</param>
        /// <returns></returns> 
        public static string ValidateXml(string filename, string schema)
        {
            XmlSchemaSet xsSet = new XmlSchemaSet();
            try
            {
                xsSet.Add(null, schema);
            }
            catch (Exception ex)
            { 
                return ex.Message;
            }
            // 定义公文模式的使用方式
            XmlReaderSettings xrSetting = new XmlReaderSettings();
            xrSetting.ValidationType = ValidationType.Schema;
            // 关联验证读取器与架构集合
            xrSetting.Schemas = xsSet;
            // 添加发生错误时的事件处理程序
            xrSetting.ValidationEventHandler += new ValidationEventHandler(MyValidationEventHandler);
            // 使用最新的方式来构建可进行校验的读取器并构造验证读取器
            XmlReader xr = XmlReader.Create(filename, xrSetting);
            // 循环检测所有的文档节点 
            try
            {
                while (xr.Read()) {}
            }
            catch (Exception ex)
            { 
                return ex.Message;
            }
            xr.Close();
            return message;
        }
        /// <summary>
        /// 验证处理
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="args"></param>
        private static void MyValidationEventHandler(object sender, ValidationEventArgs args)
        {
            if (args.Severity == XmlSeverityType.Warning)
            { 
                message = args.Message;
            }
            else
            { 
                message=args.Message;
            }
            isValidateXML = false;
        } 
    }

 /// <summary>
        /// 确定按钮
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnSubmit_Click(object sender, EventArgs e)
        {
            string path = this.txtPath.Text;
            if (string.IsNullOrEmpty(path))
            {
                MessageBox.Show("请选择文件");
                return;
            }
            FileStream stream = new FileStream(path, FileMode.Open);
            EvidenceFilesModel dep = (EvidenceFilesModel)XMLParser.Deserialize(typeof(EvidenceFilesModel), stream);
            stream.Close();

            string xml = XMLParser.Serializer(typeof(EvidenceFilesModel), dep);


            string flag = XMLValidate.ValidateXml(path, @"C:\Users\PEPE\Desktop\big.xsd");
            this.lblMsg.Text = flag;
        }