使用Regex将给定文本中的现有网址替换为新网址

Question

I'm trying to replace an existing url in given text with a new url using regex. I don't seem to get any matches for the regex pattern I'm using:

string regex = "<a href=\"http://domain/page.asp?id=(\\d+)&amp;oid=(\\d+)&amp;type=(\\w+)\">";

Can someone please assist me write a correct pattern to find urls that look like:

"<A href=\"http://domain/page.asp?id=38957&amp;oid=2497&amp;type=JPG\">"

Below is my test code which cannot find any matches for the pattern I'm using:

string result = string.Empty;

string sampleText = "<A href=\"http://domain/page.asp?id=38957&amp;oid=2497&amp;type=JPG\"><U>Click here for Terms &amp; Conditions...</U></A>";

string regex = "<a href=\"http://domain/page.asp?id=(\\d+)&amp;oid=(\\d+)&amp;type=(\\w+)\">";
        Regex regEx = new Regex(regex, RegexOptions.IgnoreCase);

result= regEx.Replace(text, "<a href=\"/newPage/Index/$1&opid=$2)\">");

Answer 1

Everything looks fine except that . and ? are special characters in regular expressions, so they need to be escaped to be treated as literals. So your expression:

string regex = "<a href=\"http://domain/page.asp?id=(\\d+)&amp;oid=(\\d+)&amp;type=(\\w+)\">";

Needs to be:

string regex = "<a href=\"http://domain/page\\.asp\\?id=(\\d+)&amp;oid=(\\d+)&amp;type=(\\w+)\">";

Note the backslashes in front of the . and ? .