XML Literals and the XML 1.0 Specification
The XML literal syntax in Visual Basic supports most of the Extensible Markup Language (XML) 1.0 specification. For details about the XML 1.0 specification, see Extensible Markup Language (XML) 1.0 on the W3C Web site.
An XML literal cannot contain a document type definition (DTD).
An XML document literal must start with an XML document declaration.
An XML literal cannot contain more than 65,535 characters on one line.
XML namespace prefixes, element names, and attribute names cannot contain more than 1,024 characters.