Regex escape questionmark and double quotes

Question

I have data with several occurrencies of the following string:

<a href="default.asp?itemID=987">

in which the itemID is always different. I am using C# and I want to get all those itemIDs with a Regular Expression.

At first I tried this

"<a href=\"default.asp?itemID=([0-9]*)\">"

But the questionmark is a reserved character. I considered using the @ operator to disable escaping of characters. But there are still some double quotes that really need escaping. So then I would go for

"<a href=\"default.asp\\?itemID=([0-9]*)\">"

which should be translated (as a string) to

<a href="default.asp\?itemID=([0-9]*)">

But the Regex.Match method gets no success. I tried the very same regex here and it worked. What am I doing wrong?

Solution 1

? and . are special chars for a regex, but can't be escaped "as is" in a string litteral. So if you put one \, it will be wrong for a string, and if you don't put \\, it will be taken as the "special char" of the regexp. So :

"@<a href=\"default\\.asp\\?itemID=([0-9]*)\">";

Solution 2

When using the @operator, you can regain double quotes with "".

You also need to escape certain special chars in the regex, in this case, the chars .\?

Try this:

@"<a href=""default\.asp\?itemID=([0-9]*)"">"

Solution 3

Try escaping the dot '.' character with \.