using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        string nextWord = FindNextWord("Message", "This Message Contains Stuff");

        Console.WriteLine(string.Format("The next word is '{0}'.", nextWord));

    }

​

    private static string FindNextWord(string word, string text)

    {

        var regex = new Regex(string.Format(@"\b{0}\b\s+(?<nextWord>[^\s]+)", word));

        var match = regex.Match(text);

        return match.Groups["nextWord"].Value;

    }

}