USERCORTROL内部的WPF依赖性Property绑定到另一个Usercontrol，不更新Coerce

Question

我有一个带有contentPresenter的家长USercontrol（NewsymbologyCombobox），该内容显示了两个控件之一。

NewsymbologyCombobox控制具有“选择”依赖性属性，

    <ContentPresenter x:Name="Presenter" >
        <!-- Presentations -->
        <ContentPresenter.Resources>
            <DataTemplate x:Key="EditablePresenter">
                <editableCombobox:EditableSymbologyComboBox SelectedOption="{Binding SelectedOption, ElementName=UserControl}" />
            </DataTemplate>
            <DataTemplate x:Key="DropdownPresenter">
                <dropdownCombobox:DropdownSymbologyComboBox SelectedOption="{Binding SelectedOption, ElementName=UserControl}" />
            </DataTemplate>
        </ContentPresenter.Resources>
        <!-- Triggers -->
        <ContentPresenter.Style>
            <Style TargetType="{x:Type ContentPresenter}">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding IsEditable, ElementName=UserControl}" Value="False">
                        <Setter Property="ContentTemplate" Value="{StaticResource DropdownPresenter}" />
                    </DataTrigger>
                    <DataTrigger Binding="{Binding IsEditable, ElementName=UserControl}" Value="True">
                        <Setter Property="ContentTemplate" Value="{StaticResource EditablePresenter}" />
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </ContentPresenter.Style>
    </ContentPresenter>

/// <summary>
        /// Property for the symbology setter to use on the plotted elements.
        /// </summary>
        public static readonly DependencyProperty SelectedOptionProperty = DependencyProperty.Register("SelectedOption", typeof(ISymbologyOption), typeof(NewSymbologyComboBox), new FrameworkPropertyMetadata(new UserDefinedSymbologyOption(""), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, PropertyChangedCallback));

        private static void PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (e.NewValue is ISymbologyOption option)
            {
                System.Diagnostics.Debug.Print(option.DisplayName); //This is not called on the coerced initial change.
            }

            
        }

---

editablesymbologycombobox和下拉杂志Bobobox也具有依赖性property selectedOption。

        public static readonly DependencyProperty SelectedOptionProperty = DependencyProperty.Register("SelectedOption", typeof(ISymbologyOption), typeof(DropdownSymbologyComboBox), new FrameworkPropertyMetadata(new UserDefinedSymbologyOption(""), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, PropertyChangedCallback, CoerceValueCallback));

下拉杂志Bobobox具有一个强制回调，如果不在可用选项中，则修改该值。

private static object CoerceValueCallback(DependencyObject d, object basevalue)
        {
            if (d is DropdownSymbologyComboBox comboBox)
            {
                if (!comboBox._isInitialized)
                    comboBox.PopulateOptions();

                if (basevalue is UserDefinedSymbologyOption userDefinedSymbology)
                {
                    var matchingOption = comboBox.AvailableOptions.FirstOrDefault(option => string.Equals(userDefinedSymbology.DisplayName, option.DisplayName, StringComparison.InvariantCultureIgnoreCase));
                    if (matchingOption != null)
                        return matchingOption;

                    return comboBox.AvailableOptions.FirstOrDefault();
                }
            }

            return basevalue;
        }

在我的窗口上，我在视图模型中显示我的默认值如图所示

        <combobox:NewSymbologyComboBox Margin="10 5 0 0" SelectedOption="{Binding PlotOptions.SelectedSymbology}" IsEditable="False"/>
        <TextBlock Text="{Binding PlotOptions.SelectedSymbology.DisplayName}"/>

，设置为“我的第一个选择”，该选项在选项中不可用，应将其胁迫到列表中的第一个项目... Coerce功能找到这并将其设置为第一个可用选项...

我遇到的问题是我的窗口没有随着此更改而更新。它显示“我的第一个选择”，直到我手动进行ComboBox进行更改。

任何帮助都很棒！谢谢