Binding not work for a custom DependencyProperty in UserControl

Question

I create a DependencyProperty as follow in a UserControl, but when i try to bind a value to in it is not working. I would be grateful if you could explain to me why it is not working and how to fix that. Regards!

    private bool _userChangeBaseValue;

    public static readonly DependencyProperty BaseValueProperty = DependencyProperty.Register("BaseValue", typeof(double?), typeof(WPFTextBoxUnitConverter),
        new PropertyMetadata(null, new PropertyChangedCallback(OnSetBaseValueChanged)));

    [Category("TextBoxUnitConverter")]
    [Description("BaseValue")]
    public double? BaseValue
    {
        get
        {
            return (double?)GetValue(BaseValueProperty);
        }
        set
        {
            SetValue(BaseValueProperty, value);
        }
    }

    private static void OnSetBaseValueChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
    {
        WPFTextBoxUnitConverter wpfTextBoxUnitConverter = dependencyObject as WPFTextBoxUnitConverter;
        wpfTextBoxUnitConverter.OnSetBaseValueChanged(e);
    }

    private void OnSetBaseValueChanged(DependencyPropertyChangedEventArgs e)
    {
        if (_userChangeBaseValue)
        {
            txtUnitCoverter.TextChanged -= txtUnitCoverter_TextChanged;
            double? newValue = e.NewValue as double?;
            ValueManager.DoubleValue = newValue;
            if (newValue.HasValue)
            {
                ValueManager.DoubleValue = ConverterToolBox.Convert(newValue.Value, BaseUnit, CurrentUnit);
            }

            double testIsConverteAble;
            bool isCanConvert = double.TryParse(txtUnitCoverter.Text, out testIsConverteAble);
            bool isEmpty = string.IsNullOrEmpty(txtUnitCoverter.Text) || string.IsNullOrWhiteSpace(txtUnitCoverter.Text);
            // Validation...
            ValidationResult validationResult = new ValidationResult();
            UnitConverterTextBoxValidation?.Invoke(this, isEmpty, isCanConvert, txtUnitCoverter.Text, BaseNumberUnit, CurrentNumberUnit, validationResult);
            ValueManager.IsValueValid(validationResult);
            txtUnitCoverter.TextChanged += txtUnitCoverter_TextChanged;
        }
    }