wpf - 装饰元素上的装饰器和事件

Question

我有一个自定义线形，它使用装饰器在该线的中间显示一个数组和一些文本。



问题是装饰元素的行为独立于装饰元素，并且不会将事件“转移”给它。在下面的代码中，我被迫手动将装饰元素重新链接到装饰元素( ta.MouseLeftButtonDown += Adorner_MouseLeftButtonDown; )，但不幸的是，即使这样也不起作用......
有人可以建议调用 this.OnMouseLeftButtonDown 时出了什么问题，为什么我没有收到相应的事件？

public class SegmentLine : Shape
{
    AdornerLayer aLayer;

    public static readonly DependencyProperty X1Property;
    public static readonly DependencyProperty X2Property;
    public static readonly DependencyProperty Y1Property;
    public static readonly DependencyProperty Y2Property;
    ...

    static SegmentLine() {
        X1Property = DependencyProperty.Register("X1", typeof(double), typeof(SegmentLine), new FrameworkPropertyMetadata(double.NaN,
            FrameworkPropertyMetadataOptions.AffectsRender));
        X2Pro...
    }

    public SegmentLine()
        : base()
    {
        this.Loaded += SegmentLine_Loaded;
    }

    void SegmentLine_Loaded(object sender, RoutedEventArgs e)
    {
        aLayer = AdornerLayer.GetAdornerLayer(this);
        if (aLayer != null)
        {
            TextAdorner ta = new TextAdorner(this);
            //ta.IsHitTestVisible = false;
            ta.MouseLeftButtonDown += Adorner_MouseLeftButtonDown;
            aLayer.Add(ta);
        }
    }

    void Adorner_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
    {
        // !! try to rise the MouseLeftButtonDown event
        this.OnMouseLeftButtonDown(e);
    }

    protected override void OnRender(DrawingContext drawingContext)
    {
        base.OnRender(drawingContext);
        if (aLayer != null)
            aLayer.Update();
    }

    class TextAdorner : Adorner
    {
        public TextAdorner(UIElement adornedElement)
            : base(adornedElement) { }

        protected override void OnRender(DrawingContext drawingContext)
        {
            // ADD LABEL ...
            FormattedText ft = new FormattedText(...);
            drawingContext.DrawText(ft, midPoint);

            // Add ARROW ...
            var myPathGeometry = new PathGeometry { Figures = myPathFigureCollection };            
            drawingContext.DrawGeometry(Brushes.Black, null, myPathGeometry);
        }
    }

    protected override System.Windows.Media.Geometry DefiningGeometry
    {
        get
        {
            var geometryGroup = new GeometryGroup();
            // Add line
            geometryGroup.Children.Add(new LineGeometry(new Point(X1, Y1), new Point(X2, Y2)));
            return geometryGroup;
        }
    }    
}

Answer 1

您应该调用 this.RaiseEvent(e);而不是 this.OnMouseLeftButtonDown(e);将事件转移到装饰元素。
顺便说一句，您可以只使用一个事件处理程序来传输多种事件类型

void SegmentLine_Loaded(object sender, RoutedEventArgs e)
{
    ..
    ta.MouseLeftButtonDown += Adorner_AnyEvent;
    ta.MouseRightButtonDown += Adorner_AnyEvent;
}

void Adorner_AnyEvent(object sender, RoutedEventArgs e)
{
    this.RaiseEvent(e);
}