如何將InkToolbar鏈接到CustomControl內的InkCanvas？

Question

我正在創建一個包含InkCanvas的CustomControl。 現在的問題是如何將InkToolbar （在CustomControl之外）鏈接到InkCanvas （在CustomControl中）？

解決方案：

我嘗試使用下面的代碼將InkCanvas外的InkCanvas ，但它無法正常工作 。

這是我的代碼 （我試過的解決方案不起作用 ）：

//In CustomControl Code Behind
InkCanvas PATH_INK_CANVAS;

protected override void OnApplyTemplate()
{
    PATH_INK_CANVAS = GetTemplateChild<InkCanvas>("PATH_INK_CANVAS");
}

T GetTemplateChild<T>(string elementName) where T : DependencyObject
{
    var element = GetTemplateChild(elementName) as T;
    if (element == null)
        throw new NullReferenceException(elementName);
    return element;
}

public InkCanvas InkCanvas
{
    get { return PATH_INK_CANVAS; }
}

public static readonly DependencyProperty InkCanvasProperty =
    DependencyProperty.Register("InkCanvas", typeof(InkCanvas), typeof(RichInkTextBox), new PropertyMetadata(0));

//In CustomControl XAML
<Style>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate>
                <Grid Name="MainGrid" Width="{TemplateBinding Width}" Height="{TemplateBinding Height}">
                    <InkCanvas Name="PATH_INK_CANVAS" Canvas.ZIndex="-1"/>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

//In Page
<local:CustomControl x:Name="MyCustomControl"/>
<InkToolbar Grid.Row="0" TargetInkCanvas="{x:Bind MyCustomControl.InkCanvas}"/>

Answer 1

我不認為這是定義只讀依賴項屬性的正確語法。 嘗試類似以下的內容 -

public InkCanvas InkCanvas
{
    get => (InkCanvas)GetValue(InkCanvasProperty);
    private set => SetValue(InkCanvasProperty, value);
}
public static readonly DependencyProperty InkCanvasProperty = DependencyProperty.Register(
    "InkCanvas", typeof(InkCanvas), typeof(InkCanvasWrapper), new PropertyMetadata(null));

此外，請確保將Mode設置為x:Bind為OneWay因為InkCanvas依賴項屬性的默認值為null （您將默認值設置為0 ，這是錯誤的）。

<InkToolbar Grid.Row="0" TargetInkCanvas="{x:Bind MyCustomControl.InkCanvas, Mode=OneWay}" />