WPF 绑定属性不更新源值

Question

我的自定义控件中有DependencyProperty。我将它绑定到某个对象中的某个属性。当我的控件出现时，它会从源中获取值并将其应用于自身。但是当我在输入字段中输入内容时，源值不会改变。我做错了什么？

控制声明：

public class ScriptComponentField : Control
{
    public enum Datatype
    {
        String,
        Integer,
        Real,
        Boolean,
        Enumerable,
        Code
    }

    public string Header
    {
        get { return (String)GetValue(HeaderProperty); }
        set { SetValue(HeaderProperty, value); }
    }
    public static readonly DependencyProperty HeaderProperty = DependencyProperty.RegisterAttached(nameof(Header), typeof(string), typeof(ScriptComponentField), new PropertyMetadata(""));

    public object Value
    {
        get { return GetValue(ValueProperty); }
        set { SetValue(ValueProperty, value); }
    }
    public static readonly DependencyProperty ValueProperty = DependencyProperty.RegisterAttached(nameof(Value), typeof(object), typeof(ScriptComponentField), new PropertyMetadata(null));

    public Datatype ValueType
    {
        get { return (Datatype)GetValue(ValueTypeProperty); }
        set { SetValue(ValueTypeProperty, Value); }
    }
    public static readonly DependencyProperty ValueTypeProperty = DependencyProperty.RegisterAttached(nameof(ValueType), typeof(Datatype), typeof(ScriptComponentField), new PropertyMetadata(Datatype.String));

    public List<string> EnumerableItems
    {
        get { return (List<string>)GetValue(EnumerableItemsProperty); }
        set { SetValue(EnumerableItemsProperty, Value); }
    }
    public static readonly DependencyProperty EnumerableItemsProperty = DependencyProperty.RegisterAttached(nameof(EnumerableItems), typeof(List<string>), typeof(ScriptComponentField), new PropertyMetadata(null));

    static ScriptComponentField()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(ScriptComponentField), new FrameworkPropertyMetadata(typeof(ScriptComponentField)));
    }
}

属性Value 具有object 类型只是因为它可以包含string、bool、int 等任何值。

控制模板：

<Style TargetType="{x:Type Controls:ScriptComponentField}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Controls:ScriptComponentField}">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="150" SharedSizeGroup="name"/>
                        <ColumnDefinition SharedSizeGroup="value"/>
                    </Grid.ColumnDefinitions>
                    <Label Content="{TemplateBinding Header}" HorizontalAlignment="Right" VerticalAlignment="Center"/>
                    <TextBox x:Name="InputString" Visibility="Collapsed" Grid.Column="1" Text="{TemplateBinding Value}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" VerticalContentAlignment="Center" Margin="0,2"/>
                    <Advanced:IntegerUpDown x:Name="InputInteger" Visibility="Collapsed" Grid.Column="1" Value="{TemplateBinding Value}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" VerticalContentAlignment="Center" Margin="0,2"/>
                    <CheckBox x:Name="InputBoolean" Visibility="Collapsed" Grid.Column="1" IsChecked="{TemplateBinding Value}" VerticalAlignment="Center"/>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="ValueType" Value="String">
                        <Setter TargetName="InputString" Property="Visibility" Value="Visible"/>
                    </Trigger>
                    <Trigger Property="ValueType" Value="Integer">
                        <Setter TargetName="InputInteger" Property="Visibility" Value="Visible"/>
                    </Trigger>
                    <Trigger Property="ValueType" Value="Boolean">
                        <Setter TargetName="InputBoolean" Property="Visibility" Value="Visible"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Answer 1

问题是你使用TemplateBinding。 TemplateBinding 始终是 OneWay。如果您将TemplateBinding 更改为TwoWay Binding 和RelativeSource 或ElementName，它将起作用。

<TextBox x:Name="InputString" Visibility="Collapsed" Grid.Column="1" Text="{Binding Value, RelativeSource={RelativeSource AncestorType=Controls:ScriptComponentField}, Mode=TwoWay}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" VerticalContentAlignment="Center" Margin="0,2"/>

Answer 2

您可能错过了“Mode=TwoWay”属性，如下所示：

<Button x:Name="btnMy" Content="{Binding MyText, Mode=TwoWay}" />

默认控件绑定是“OneWay”（参见下面的编辑），它“在绑定源（源）更改时更新绑定目标（目标）属性”。 © MSDN 链接如下

TwoWay Binding：“导致对源属性或目标属性的更改以自动更新另一个” © MSDN 链接如下

MSDN BindingMode

编辑：

正如 Clemens 所说，关于默认绑定模式： “默认模式是在注册属性期间由 FrameworkPropertyMetadataOptions 设置的。” © 克莱门斯
很短，它并不总是 OneWay，但大多数时候。