using System; using System.Collections.Generic; using System.IO; using System.Linq; using System.Text.RegularExpressions; public class Test { public static void Main() { var methodArgumentType = "IDictionary"; if (methodArgumentType.Contains("<") && methodArgumentType.Contains(">")) { methodArgumentType = Regex.Replace(methodArgumentType, @"<([^<>]+)>", m => string.Format("<{0}>", m.Groups[1].Value.Replace(",", "#COMMA#"))); } Console.WriteLine(methodArgumentType); } }