How to tell if a string is xml?

Question

We have a string field which can contain XML or plain text. The XML contains no header, and no root element, i.e. is not well formed.

We need t

Answer 1

If your goal is reliability then the best option is to use XmlDocument.LoadXml to determine if it's valid XML or not. A full parse of the data may be expensive but it's the only way to reliably tell if it's valid XML or not. Otherwise any character you don't examine in the buffer could cause the data to be illegal XML.