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

"XmlWriter and lower ASCII characters" worked for me

string code = Regex.Replace(item.Code, @"[\u0000-\u0008,\u000B,\u000C,\u000E-\u001F]", "");