using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string input = @"{""elements"":[{""handle\~"":{""emailAddress"":""szhe@.com""},""handle"":""urn:li...""}]}";

        int a = input.IndexOf("emailAddress", 0);

        string slice = input.Substring(a);

        string[] pair = slice.Split('}');

        Console.WriteLine(pair[0]);

        Match test = Regex.Match(pair[0], @"emailAddress"":""(?<a>.*)""}.*", RegexOptions.IgnoreCase);

        Console.WriteLine("value = " + test.Groups["a"].Value);

​

        Match matchEmail = Regex.Match(input, @"emailAddress"":""(?<a>\[}])""}.*", RegexOptions.IgnoreCase);

        Console.WriteLine(matchEmail.Groups["a"].Value);

    }

​

}