Question

Currently I have a solution that builds an XML document in a number of sections and then validates the final concatenated xml against a single schema. Is it possible to use a subset of the same schema to validate each section individually?

Answer 1

The answer is yes in most of the cases. For a disclaimer, in theory someone could intentionally write an XML Schema that would make some of my proposals impossible, but then that would be just bad practice in XSD authoring.

For a straightforward solution, the following assumptions should be true:

• A section is well formed XML; you’re concatenating XmlElement nodes. E.g.:

  <section-element … attribute content>
  … more content
  </section-element>

• Each of the sections being merged has a matching global element declaration in your XML Schema set. If you use the xsi:type attribute for any of your sections, things might get a bit tricky, but not hard to fix.

The validation would be common code, where the XmlReader would be an XmlNodeReader on the node you’re concatenating. Use the XmlReaderSettings as usual…

The above would work for any XSD (you don’t have a design time dependency of knowing the XSD). For anything below, the code would have to match your XSD…

If you don’t have the matching global elements in the XML Schema then you have to look at the type of each matching local element declaration. If the type is global, then you can easily create, in memory, dummy elements that match your sections, of the global type (assuming a Venetian Blind authoring style).

If even the type is anonymous (more of a Russian Doll style), then you can even fake that, by creating a global element with a type that is a copy of the anonymous type – all in memory.