In XML, what are the nodes with question marks called, and how do I add them in C#?

Question

Here\'s an example of an XML file created in InfoPath:

Answer 1

Those are called processing instructions. You can use the XmlProcessingInstruction class to interact with them in an XmlDocument.

As with most elements defined within an XmlDocument, you cannot instantiate it directly; you must use the appropriate factory method on XmlDocument (CreateProcessingInstruction in that particular case.)