What Are Invalid Characters in Xml
I Am Working with Some Xml That Holds Strings Like: This Is a String Some of the Strings That I Am Passing to the Nodes Will Have Characters Like &, #, $, Etc...
I am working with some XML that holds strings like:
<node>This is a string</node>
Some of the strings that I am passing to the nodes will have characters like &, #, $, etc.:
<node>This is a string & so is this</node>
This is not valid due to &.
I cannot wrap these strings in CDATA as they need to be as they are. I tried looking for a list of characters that cannot be put in XML nodes without being in a CDATA.
Can someone point me in the direction of one or provide me with a list of illegal characters?
15 Answers
OK, let's separate the question of the characters that:
- aren't valid at all in any XML document.
- need to be escaped.
The answer provided by @dolmen in "" is still valid but needs to be updated with the XML 1.1 specification.
1. Invalid characters
The characters described here are all the characters that are allowed to be inserted in an XML document.
Must Read
1.1. In XML 1.0
- Reference: see XML recommendation 1.0, §2.2 Characters
The global list of allowed characters is:
[2] Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF] /* any Unicode character, excluding the surrogate blocks, FFFE, and FFFF. */
Basically, the control characters and characters out of the Unicode ranges are not allowed.
This means also that calling for example the character entity  is forbidden.
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