在代码隐藏中为 xaml 元素设置多重绑定

Question

我有以下有效的 XAML 代码，它基本上绑定了几个属性来计算用户控件的最终位置：

<UserControl x:Class="CurvePointControl"
    ....
         >
<UserControl.Resources>
    <local:VToYConverter x:Key="vToYConverter" />
</UserControl.Resources>
<UserControl.RenderTransform>
    <TranslateTransform x:Name="XTranslateTransform" >
        <TranslateTransform.Y>
            <MultiBinding Converter="{StaticResource vToYConverter}">
                <Binding ElementName="curveEditPoint" Path="V"/>
                <Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type local:CurveEditor}}" Path="MinV"/>
                <Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type local:CurveEditor}}" Path="MaxV"/>
                <Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type local:CurveEditor}}" Path="ActualHeight"/>                    
            </MultiBinding>
        </TranslateTransform.Y>
    </TranslateTransform>
</UserControl.RenderTransform>

...

由于各种原因（但特别是为了避免相对源，我现在尝试在后面的代码中执行相同的操作，但没有成功。

这是我当前的代码：

    public CurvePointControl(CurveEditor CV)
    {
        InitializeComponent();

        MultiBinding multiBinding = new MultiBinding();
        multiBinding.Converter = m_VToYConverter;

        multiBinding.Bindings.Add(new Binding("V"));
        multiBinding.Bindings.Add(new Binding(CV.MinVProperty)); // doesn't work
        multiBinding.Bindings.Add(new Binding(CV.MaxVProperty)); // doesn't work
        multiBinding.Bindings.Add(new Binding(CV.ActualHeight)); // doesn't work       
        multiBinding.NotifyOnSourceUpdated= true;

        this.SetBinding(TranslateTransform.YProperty, multiBinding);
        //Doesn't work too:
        //BindingOperations.SetBinding(XTranslateTransform, TranslateTransform.YProperty, multiBinding);

    }

我仍然不敢相信将 XAML 转换为 C# 代码是如此困难。转换器仅被调用一次并且没有有效的属性值。

知道出了什么问题吗？ 我该如何调试这样的问题？

Answer 1

您需要来源：

multiBinding.Bindings.Add(new Binding("V") { Source = curveEditPoint }); //If that object is accessible in the current scope.
multiBinding.Bindings.Add(new Binding("MinV") { Source = CV });
multiBinding.Bindings.Add(new Binding("MaxV") { Source = CV });
multiBinding.Bindings.Add(new Binding("ActualHeight") { Source = CV });

Answer 2

直译是：

MultiBinding multiBinding = new MultiBinding();
multiBinding.Converter = m_VToYConverter;

RelativeSource relativeSource = new RelativeSource() { AncestorType = typeof(CurveEditor) };

multiBinding.Bindings.Add(new Binding("V") { ElementName = "curveEditPoint" });
multiBinding.Bindings.Add(new Binding(CV.MinVProperty) { RelativeSource = relativeSource });
multiBinding.Bindings.Add(new Binding(CV.MaxVProperty) { RelativeSource = relativeSource });
multiBinding.Bindings.Add(new Binding(CV.ActualHeight) { RelativeSource = relativeSource });

但是您可能会遇到 ElementName 正确解析的问题。在这种情况下，您必须直接绑定到该元素或“查找”它。如果 curveEditPoint 是当前类中的字段，则类似这样的操作会起作用：

multiBinding.Bindings.Add(new Binding("V") { Source = this.curveEditPoint });

Answer 3

尝试使用

multiBinding.Bindings.Add(new Binding("MinVProperty") { ElementName = CV.Name });

而不是

multiBinding.Bindings.Add(new Binding("CV.MinVProperty"));