using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var wsChars = Enumerable.Range(0, ushort.MaxValue).Where(c => char.IsWhiteSpace(Convert.ToChar(c))).Select(c => Convert.ToChar(c)).ToArray();

        Console.WriteLine(wsChars.Length);

        var someText = "This_is_a\tstring with \nsome whitespace characters.";

        Console.WriteLine(someText.IndexOfAny(wsChars));

    }

​

}