What are invalid characters in XML

Question

I am working with some XML that holds strings like:

This is a string

Some of the strings that I am passing to the

Answer 1

The only illegal characters are &, < and > (as well as " or ' in attributes).

They're escaped using XML entities, in this case you want & for &.

Really, though, you should use a tool or library that writes XML for you and abstracts this kind of thing away for you so you don't have to worry about it.