Validating and reparing xml

Question

Is there a way to get more useful information on validation error? XmlSchemaException provides the line number and position of the error which makes little sense to me. Xml document after all is not about its transient textual representation. I'd like to get an enumerated error (or an error code) specifying what when wrong, node name (or an xpath) to locate the source of the problem so that perhaps I can try and fix it.

Edit: I'm talking about valid xml documents - just not valid against a particular schema!

Answer 1

You can accomplish this, sort of, by setting up an XmlReader whose XmlReaderSettings contain the schema and then using it to read through the input stream node by node. You can keep track of the last node read and have a pretty good idea of where you are in the document when a validation error happens.

I think that if you try this exercise, you'll discover that there are a lot of validation errors (e.g. required element missing) where the concept of the error node doesn't make much sense. Yes, the parent element is clearly what's in error in that case, but what really triggered the error was the reader encountering the end tag without ever seeing the required element, which is why the error line and position point at the end tag.

Answer 2

In my experience, you are lucky to get a line number and parse position.

Answer 3

You might consider validating via a DTD which can sometimes give slightly more interesting errors, however, on a project I currently work on, we validate using XSLTs. The transform checks the syntax and reports errors as outputted transform text. I would consider that route if you want more friendly error checking. For us, an empty output means no errors, otherwise we get some nice detail from the XSLT processing on what the error was and where.

Answer 4

personally I'm not sure how to get a more detailed error, typcially f you open the document and go to the location mentioned you can easily find the error.

If the code isn't able to parse the file as valid XML, it is pretty hard for it to give an XPATH or other named XML detail.

Answer 5

It seems this is no easy task. Robert Rossney's answer comes closest to programmaticaly solving my problem so I'll accept that for now. I'll continue using the xsl solution. Anyone finding a better way to resolve validation errors can respond to this thread.