Prizm.Domain.Entity.Project.FormRegExp C# (CSharp) Method

        public static string FormRegExp(string millPipeNumberMask)
        {
            List<char> specialCharacters = new List<char> { '.', '(', ')', '*', '+', '|', '{', '}', '^', '[', ']', '-', '\\', ',' };
            StringBuilder mask = new StringBuilder();
            if (millPipeNumberMask != string.Empty && millPipeNumberMask != null)
            {
                foreach (char ch in millPipeNumberMask)
                {
                    string convertedToRegex = "";
                    if (specialCharacters.Contains(ch))
                    {
                        convertedToRegex = @"\" + ch;
                    }
                    else
                    {
                        switch (ch)
                        {
                            case '#': convertedToRegex = @"\d"; break;
                            case '@': convertedToRegex = @"\p{Lu}"; break;
                            case '%': convertedToRegex = @"(\d|\p{Lu})"; break;
                            case '?': convertedToRegex = @"\w"; break;

                            default: convertedToRegex = ch.ToString(); break;
                        }
                    }
                    mask.Append(convertedToRegex);
                }
            }
            return mask.ToString();
        }
    }