AjaxControlToolkit.MaskedEditCommon.GetValidMask C# (CSharp) Method

        public static string GetValidMask(string text)
        {
            var ini = GetFirstMaskPosition(text);
            var fim = GetLastMaskPosition(text);
            text = ConvertMask(text);

            return text.Substring(ini, fim - ini + 1);
        }

        private bool validateMaskType()
        {
            string         mask     = Mask;
            MaskedEditType maskType = MaskType;

            if (!string.IsNullOrEmpty(mask) && (maskType == MaskedEditType.Date || maskType == MaskedEditType.Time))
            {
                string validMask = MaskedEditCommon.GetValidMask(mask);
                switch (maskType)
                {
                case MaskedEditType.Date:
                    return(Array.IndexOf(new string[] { "99/99/9999", "99/9999/99", "9999/99/99", "99/99/99" }, validMask) >= 0);

                case MaskedEditType.Time:
                    return(Array.IndexOf(new string[] { "99:99:99", "99:99" }, validMask) >= 0);

                case MaskedEditType.DateTime:
                    return(Array.IndexOf(new string[] { "99/99/9999 99:99:99", "99/99/9999 99:99", "99/9999/99 99:99:99", "99/9999/99 99:99", "9999/99/99 99:99:99", "9999/99/99 99:99", "99/99/99 99:99:99", "99/99/99 99:99" }, validMask) >= 0);

                case MaskedEditType.Number:
                    foreach (char ch in validMask)
                    {
                        if (ch != '9' && ch != '.' && ch != ',')
                        {
                            return(false);
                        }
                    }
                    break;
                }
            }
            return(true);
        }