var field = new NumericField()
{
    Width                        = FieldLength.Auto,
    Name                         = $"RefData{no}",
    Label                        = $"{item.Name} ({item.Unit})",
    DataType                     = typeof(double),
    AllowEdit                    = true, 
    Format                       = Datas.RefFormat,
    EditorStyle                  = m_view.TryFindResource("Stype_NumericMaskedEditor") as Style,
    HorizontalContentAlignment   = System.Windows.HorizontalAlignment.Right
};

this.m_view.U_FieldLayout.Fields.Add(field);

<Style x:Key="Stype_NumericMaskedEditor" TargetType="{x:Type igEditors:XamNumericEditor}">
    <Setter Property="Mask" Value="{}{double:4.10}" />
    <Setter Property="InvalidValueBehavior" Value="RevertValue" />
    <Setter Property="AcceptsArrowKeysInEditMode" Value="False" />
    <Setter Property="ValueConstraint">
        <Setter.Value>
            <igEditors:ValueConstraint MaxInclusive="9999.99"
                                       MinInclusive="0"
                                       Nullable="False" />
        </Setter.Value>
    </Setter>
</Style>

 private string _RefData1 = "0";
 public string RefData1
 {
     get { return _RefData1; }
     set
     {
         _RefData1 = value;
         OnPropertyChanged("RefData1");
     }
 }

If I set the initial value of RefData1 to "0", it will be displayed as the initial value when the unbound field is added. However, I want the field to remain blank until a value is entered.

When I set RefData1 to an empty string (""), val becomes null in the SetDataValueHelper method. While this behavior is expected, how can I achieve my desired behavior?