RandomString

    private static string RandomString(int size, bool lowerCase)
    {
        Random random = new Random(Guid.NewGuid().ToString().GetHashCode());

        StringBuilder builder = new StringBuilder();

        char ch;
        for (int i = 1; i < size+1; i++)
        {
            ch = Convert.ToChar(Convert.ToInt32(Math.Floor(26 * random.NextDouble() + 65)));
            builder.Append(ch);
        }
        if (lowerCase)
            return builder.ToString().ToLower();
        else
            return builder.ToString();
    }