Match escaped html in regex c#

Question

How can I escape html codes in Regex?

I need to find the string

&amp;

in a string like

this is my string &amp; this is another string

I can not use HtmlEncode/Decode for this purpose cause i need work with tags. That i want i just find the common string.

I use this, and work for example with "another" or "my" but doesn't work with "&".

            Regex regularextest = new Regex("\b&amp;\b", options);
            string RSTest = "char $& morechar";
            string lalala = regularextest.Replace("foo &amp; bar", RSTest);

It's very frustrating because google replaces the string with an & or "AND" word.

Thanks in advance

Why do you need to use regex as opposed to the normal `.Replace()` on the string? — recursive, Nov 23 '11 at 18:54
In addition, in the MSDN says that & and ; are not special chars for Regex in C# — Leandro Bardelli, Nov 23 '11 at 18:54
See http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454 I know it's not an exact duplicate, but it answers your question. Parsing escaped html faces the same limitations. — David, Nov 23 '11 at 18:54
I don't understand why you say "I can not use HtmlEncode/Decode ... cause i need work with tags" - could you elaborate? — jwd, Nov 23 '11 at 18:55
Because the logic of the code, the regular expression it's so much complicated, i reduce it to do the example and find the solution — Leandro Bardelli, Nov 23 '11 at 18:56
@jwd - Perhaps ***I'm*** the one who misread the question. ;-) — David, Nov 23 '11 at 18:57

score 2 · Accepted Answer · answered Nov 23 '11 at 18:55

2

This \b&\b will not match because & and ; are not word characters.

You could try this :

Regex regularextest = new Regex("(?<=^|\s+)&amp;(?=\s+|$)", options);

answered Nov 23 '11 at 18:55

FailedDev

26,680
9
53
73

i never think it... of course... maybe is that. Let me try it! :) Thanks for the tip. – Leandro Bardelli Nov 23 '11 at 19:13
1

@Leandro I am just a guy :) but thanks anyway. There **way** more experienced people in regexes in SO. – FailedDev Nov 23 '11 at 19:16

score 0 · Answer 2 · answered Nov 23 '11 at 19:21

If you need to identify/convert valid entities (non-unicode), you could use this regex
(?:&(?:[A-Za-z_:][\w:.-]*|\#(?:[0-9]+|x[0-9a-fA-F]+));)
to identify a possible value to replace, pass it to a callback function that further process the entity you wish to replace. This way it could all be done in a single regex global replace (with callback logic).

Match escaped html in regex c#

2 Answers2