“未声明\'http://www.w3.org/XML/1998/namespace:lang\'属性。”

System.Xml.Schema.XmlSchemaValidationException: 
\"The \'http://www.w3.org/XML/1998/namespace:lang\' attribute is not declared.\"

<xs:schema id=\"myschemaId\"
       xmlns:xs=\"http://www.w3.org/2001/XMLSchema\"
       targetNamespace=\"http://mytargetnamespace.com\"
       xmlns=\"http://mytargetnamespace.com\"
       xmlns:mm=\"http://mytargetnamespace.com\"
       elementFormDefault=\"qualified\">
 <xs:import namespace=\"http://www.w3.org/XML/1998/namespace\" 
            schemaLocation=\"http://www.w3.org/2001/xml.xsd\" />
 ...

<root xmlns=\"http://mytargetnamespace.com\"        
      xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"
      xsi:schemaLocation=\"http://mytargetnamespace.com myschema.xsd\">

const XmlSchemaValidationFlags validationFlags =
          XmlSchemaValidationFlags.ProcessInlineSchema |
          XmlSchemaValidationFlags.ProcessSchemaLocation |  
          XmlSchemaValidationFlags.ReportValidationWarnings |
          XmlSchemaValidationFlags.AllowXmlAttributes;

// Set the validation settings.
var settings = new XmlReaderSettings
                   {
                       ValidationType = ValidationType.Schema,
                       ValidationFlags = validationFlags,
                       DtdProcessing = DtdProcessing.Parse
                   };
settings.ValidationEventHandler += OnValidationEventHandler;

// Create the XmlReader object.
var reader = XmlReader.Create(_xmlFilePath, settings);

// Parse the file. 
while (reader.Read()) {}