valid children of XmlNode according to DTD?

Question

consider this:

I'm inside a (selfbuilt) XML Editor and am about to add a Child to an XmlNode. How do I know which types of children are valid according to a DTD.

it's a behaviour like Intellisense. I couldn't find any .NET classes for "parsing" the DTD.

How would i go about this?

Answer 1

Unfortunately, the DOM Level 1 Core standard which XmlDocument implements does not provide any access to <!ELEMENT> and <!ATTLIST> declarations in a DTD (internal subset or, if configured to read it, external DTD).

You do get Document.DocumentType.Entities, which tells you what general entities (&something;) were defined in the DTD, and Notations, which is largely useless, but not Elements or Attlists. Whilst there exist DOMs that will retain this information, I'm not aware of any for .NET (unless you want to go running pxdom through IronPython, which would probably be a bit of a pain and not at all fast) and nothing that integrates with System.Xml.

You could possibly hook up saxdotnet, using a declHandler (looks like eg. ExpatReader.SetDeclHandlerForParsing in saxdotnet) to pick up these declarations. Either as a separate parse process for the internalSubset/systemId DTD, or as a replacement for .NET's own parsing, converting the event stream in an XmlDocument manually.