How to Toggle String Case in .Net

This one should outperform both the other methods for longer strings because of the StringBuilder.string s = "AbCdEfGhI§$%&/()1234567890";var sb = new StringBuilder(s.Length);foreach (char c in s) sb.Append(char.IsUpper(c) ? char.ToLower(c) : char.ToUpper(c));s =...