Mask for blazor input

Mask.cs

    private void ProcessMask()
    {
        var newValue = new StringBuilder();
        var maskIndex = 0;
        var valueIndex = 0;

        while (valueIndex < Value?.Length)
        {
            if (maskIndex >= Mask?.Length)
                break;

            switch (Mask?[maskIndex])
            {
                case '0' when char.IsNumber(Value[valueIndex]):
                    newValue.Append(Value[valueIndex]);
                    valueIndex++;
                    break;
                case '#' when char.IsLetterOrDigit(Value[valueIndex]):
                    newValue.Append(Value[valueIndex]);
                    valueIndex++;
                    break;
                default:
                {
                    if (Mask?[maskIndex] != '0' && Mask?[maskIndex] != '#')
                    {
                        newValue.Append(Mask?[maskIndex]);
                        if (Mask?[maskIndex] == Value[valueIndex])
                        {
                            valueIndex++;
                        }
                    }

                    break;
                }
            }

            maskIndex++;
        }

        Value = newValue.ToString();
    }