Use Variable in Regex

Question

I am trying to use a variable in my regex pattern. This variable will always change and never be the same.

Whenever I try to use it in the pattern it gives me an error. Since the variable im using is a path, it sees "\" as an escape sequence and whichever letter as well so for example "c:\users" would be seen as "\u" which gives me an error.

I was wondering if there is any way around this, like i said this variable is always changing and hard coding any values wouldn't work.

Here is my existing code for the regex pattern:

public static Boolean validateFilePath(String dstPath, String newFileDstPath)
{
   Boolean blnflag = false;
   Match m = Regex.Match(newFileDstPath, @""+ dstPath + "");

   if (m.Success)
   {
      blnflag = true;
   }
   return blnflag;
}

Are you even using any regular expression patterns in `dstPath`? If not just use String.Contains so you don't have to worry about escaping. — shf301, Apr 25 '14 at 18:34

score 6 · Answer 1 · answered Apr 25 '14 at 18:32

6

Use the Regex.Escape method? See http://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex.escape(v=vs.110).aspx

answered Apr 25 '14 at 18:32

sovemp

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score 1 · Answer 2 · answered Apr 25 '14 at 18:34

If you READ THE DOCUMENTATION, you will discover the method Regex.Escape(), which will probably serve your purpose.

Some other notes:

Why are you doing this: @"" + dstPath + "" That resolves to dstPath, unchanged.
Why are you trying to use regular expressions for something that might be better addressed by using string.StartsWith() and/or the method and properties of System.IO.Path

Use Variable in Regex

2 Answers2