Question

I have a xml file. As per my requirement I need to update empty tag such as I need to change <xml></xml> to <xml/>. Is it possible to change the tags like that..

Thank you…

Answer 1

var xmlString="<xml></xml> <toto></toto>";
var properString=System.Text.RegularExpressions.Regex.Replace(xmlString, "<([^>]+)></[^>]+>", "<$1/>");

EDIT: explanation!

@Neil Knight has already provided, in a comment, a link to Wikipedia explaining the concept of regular expressions. The part specific to .NET is available here: .NET Framework Regular Expressions

A starting XML tag can be matched with the following regular expression: <[^>]+>. The [^>]+ part can be read as: all characters that are not “>”, with at least one character (so <> is not matched but <a> is). An ending XML tag can be matched with the same kind of expression: </[^>]+> (note the slash after the first character). So the regular expression <[^>]+></[^>]+> matches empty tags such as <foo></foo> (but be careful, it also matches <foo></bar> which is not valid XML code).

What we need now is to isolate the characters between “<” and “>”. For that, we use parenthesis: <([^>]+)>. This instructs the regular expression engine to capture the matched characters. Each group of parenthesis can be referred later in a replacement operation by the “$x” string (where “x” is a number: “$1” for the first matching parenthesis, “$2” for the second one, etc.).

So, with a call to Regex.Replace(xmlString, "<([^>]+)></[^>]+>", "<$1/>"), <foo></foo> will be replaced by <foo/> (“foo” characters are captured, and “$1” is replaced by them). <foo></bar> will also be replaced by <foo/>.

I hope that this explanation is enough for @Felix K. ;o)
(my English is not so good, that’s why I did not provide many details)