using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        // The original string to search within.

        string s = "NumberofCars: 12\r\nNumberofBikes: 3\r\nNumberofShoes: 6";

        // The search value.

        string search = "NumberofBikes";

        // Define a regular expression for executing the search.

        Regex rgx = new Regex(search + @".*?(\d+?)", RegexOptions.IgnoreCase);

        // Find matches.

        MatchCollection matches = rgx.Matches(s);

        if (matches.Count > 0 && matches[0].Groups.Count > 1) //At least one match was found and has a capturing group.

        {

            Console.WriteLine(matches[0].Groups[1]); //Return the first capturing group of the first match.

        }

    }

}