如何在WPF中处理Canvas.Top更改事件？ [英] How do I handle Canvas.Top change event in WPF?

问题描述

我有一个元素放置在 Canvas 使用附加属性 Canvas.Top 和 Canvas .Left 。然后使用动画将元素移动到不同的坐标集，如下所示：

I have an element positioned on Canvas using attached properties Canvas.Top and Canvas.Left. Then using animations the element is moved to different set of coordinates, like this:

DoubleAnimation left = new DoubleAnimation( oldLeft, newLeft );
DoubleAnimation top = new DoubleAnimation( oldTop, newTop );

element.BeginAnimation( Canvas.LeftProperty, left );
element.BeginAnimation( Canvas.TopProperty, top );

有 Canvas.Top 或 Canvas.Left 已更改？最好与动画无关。

Is there a way to receive events whenever Canvas.Top or Canvas.Left is changed? Preferably without relation to animation.

推荐答案

可以 DependencyPropertyDescriptor ，可以使用' AddValueChanged 方法：

var descriptor 
    = DependencyPropertyDescriptor.FromProperty( 
        Canvas.LeftProperty, typeof( YourControlType ) 
      );
descriptor.AddValueChanged( this, OnCanvasLeftChanged );

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