XML Exception: Invalid Character(s)

Answer 1

If your input is not XML, you should use something like Tidy or Tagsoup to clean the mess up.

They would take any input and try, hopefully, to make a useful DOM from it.

I don't know how relevant dark side libraries are called.

Answer 2

Would something as described in this blog post be helpful?

Basically, he creates a sanitizing xml stream.

Answer 3

Garbage In, Garbage Out. If the remote application is sending you garbage, then that's all you'll get. If they think they're sending XML, then they need to be fixed. In this case, you're not doing them any favors by working around their bug.

You should also make sure of what they think they're sending. What did the %1C mean to them? What did they want it to be?

Answer 4

IMHO the best solution would be to modify the code/program/whatever produced the invalid XML that is being fed to your program. Unfortunately this is not always possible. In this case you need to escape all characters < 0x20 before trying to load the document.

Answer 5

If you really can't fix the source XML data, consider taking an approach like I described in this answer. Basically, you create a TextReader subclass (e.g StripTextReader) that wraps an existing TextReader (tr) and discards invalid characters.

Answer 6

XML can handle just about any character, but there are ranges, control codes and such, that it won't.

Your best bet, if you can't get them to fix their output, is to sanitize the raw data you're receiving. You need replace illegal characters with the character reference format you noted.

(You can't even resort to CDATA, as there is no way to escape these characters there.)