C# – Validate XML against XSD and ignore order of child elements

cvalidationxmlxsd

I have a method in a C# app that validates a user input XML file against an embedded XSD. It works just fine, but it requires that all the child elements be in the exact order defined in the XSD. To me though, the order doesn't matter so long as the elements exist.

For example, if I had the following XSD…

<xs:element maxOccurs="unbounded" name="ParentElement">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="FirstChildElement" type="xs:string" />
      <xs:element name="SecondChildElement" type="xs:string" />
      <xs:element name="ThirdChildElement" type="xs:string" />
    </xs:sequence>
  </xs:complexType>
</xs:element>

And an XML like this…

<ParentElement>
    <FirstChildElement>someValue</FirstChildElement>        
    <ThirdChildElement>someValue</ThirdChildElement>
    <SecondChildElement>someValue</SecondChildElement>
</ParentElement>

If I validated it I'd get an error because the child elements are out of order.

Can I make some change to the XSD so validation only cares if the elements exist, and that they're under the correct parent, but not what order they're in?

Best Answer

Sequence means, the elements must appear in the specific order. You probably want xs:all. Take a look at http://www.w3schools.com/xml/schema_complex_indicators.asp

Related Solutions

Java – What’s the best way to validate an XML file against an XSD file

The Java runtime library supports validation. Last time I checked this was the Apache Xerces parser under the covers. You should probably use a javax.xml.validation.Validator.

import javax.xml.XMLConstants;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.*;
import java.net.URL;
import org.xml.sax.SAXException;
//import java.io.File; // if you use File
import java.io.IOException;
...
URL schemaFile = new URL("http://host:port/filename.xsd");
// webapp example xsd: 
// URL schemaFile = new URL("http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd");
// local file example:
// File schemaFile = new File("/location/to/localfile.xsd"); // etc.
Source xmlFile = new StreamSource(new File("web.xml"));
SchemaFactory schemaFactory = SchemaFactory
    .newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
try {
  Schema schema = schemaFactory.newSchema(schemaFile);
  Validator validator = schema.newValidator();
  validator.validate(xmlFile);
  System.out.println(xmlFile.getSystemId() + " is valid");
} catch (SAXException e) {
  System.out.println(xmlFile.getSystemId() + " is NOT valid reason:" + e);
} catch (IOException e) {}

The schema factory constant is the string http://www.w3.org/2001/XMLSchema which defines XSDs. The above code validates a WAR deployment descriptor against the URL http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd but you could just as easily validate against a local file.

You should not use the DOMParser to validate a document (unless your goal is to create a document object model anyway). This will start creating DOM objects as it parses the document - wasteful if you aren't going to use them.

Java – Ignore element order while validating XML against XSD

What you are asking for is a way to say "validate some of the XSD and ignore other parts". I don't think that can be done.

One possible solution would be to modify the schema so that instead of using a <sequence> for those elements (which requires that the elements be in a particular order) you can use <all>, which allows the elements to be in any order.

The point of a schema is to impose certain structure and requirements on an XML document. You can't just say "eh, I don't like that particular part of the schema, ignore it" as then the document doesn't conform to the schema anymore.

Related Topic