An XML literal can span multiple lines without using line continuation characters (the space-underscore-enter sequence). This makes it easier to compare XML literals in code with XML documents.
The compiler treats line continuation characters as part of an XML literal. Therefore, you should use the space-underscore-enter sequence only when it belongs in the LINQ to XML object.
However, you do need line continuation characters if you have a multiline expression in an embedded expression. For more information, see Embedded Expressions in XML.