System.ComponentModel.MaskedTextProvider.IsAvailablePosition C# (CSharp) Method

        public bool IsAvailablePosition(int position)
        {
            if (position < 0 || position >= _testString.Length)
            {
                return false;
                //throw new ArgumentOutOfRangeException("position");
            }

            CharDescriptor chDex = _stringDescriptor[position];
            return IsEditPosition(chDex) && !chDex.IsAssigned;
        }