соединяет список строк

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Create a List of 3 strings.
        var list = new List<string>() { "cat", "dog", "rat" };
        // Join the strings from the List.
        string joined = string.Join<string>("*", list);
        // Display.
        Console.WriteLine(joined);
    }
}
PrashantUnity