How to write REGEX to get the particular string in C# ASP.NET?

If all you want is the numbers from a string then you could use the regex in this code:

        string re = "(?:\b(\d+)\b[^\d]*)+";
        Regex regex = new Regex(re);

        string input = "componentStatusId==2|3,screeningOwnerId>0";

        MatchCollection matches = regex.Matches(input);

        for (int ii = 0; ii < matches.Count; ii++)
        {
            Console.WriteLine("Match[{0}]  // of 0..{1}:", ii, matches.Count - 1);
            DisplayMatchResults(matches[ii]);
        }

Function DisplayMatchResults is taken from this Stack Overflow answer.

The Console output from the above is:

Match[0]  // of 0..0:
Match has 1 captures
  Group  0 has  1 captures '2|3,screeningOwnerId>0'
       Capture  0 '2|3,screeningOwnerId>0'
  Group  1 has  3 captures '0'
       Capture  0 '2'
       Capture  1 '3'
       Capture  2 '0'
    match.Groups[0].Value == "2|3,screeningOwnerId>0"
    match.Groups[1].Value == "0"
    match.Groups[0].Captures[0].Value == "2|3,screeningOwnerId>0"
    match.Groups[1].Captures[0].Value == "2"
    match.Groups[1].Captures[1].Value == "3"
    match.Groups[1].Captures[2].Value == "0"

Hence the numbers can be seen in match.Groups[1].Captures[...].

Another possibility is to use Regex.Split where the pattern is "non digits". The results from the code below will need post processing to remove empty strings. Note that Regex.Split does not have the StringSplitOptions.RemoveEmptyEntries of the string Split method.

        string input = "componentStatusId==2|3,screeningOwnerId>0";
        string[] numbers = Regex.Split(input, "[^\d]+");
        for (int ii = 0; ii < numbers.Length; ii++)
        {
            Console.WriteLine("{0}:  '{1}'", ii, numbers[ii]);
        }

The output from this is:

0:  ''
1:  '2'
2:  '34'
3:  '0'