获取父级的高度

Question

我在运行时使用矩形和拇指创建画布作为一个孩子。 我想访问父级高度，我的父级是由其子级调用的发送者事件中的画布。画布是在运行时创建的。在变量 p 中，我想访问父母的身高。

    private void Rectangle_Click(object sender, RoutedEventArgs e)
    {
        var canvas = new Canvas();
        canvas.Height = 100;
        canvas.Width = 100;
        canvas.Background = new SolidColorBrush(Colors.Violet);

        var thumb = new Thumb();
        thumb.Background = new SolidColorBrush(Colors.LimeGreen);

        var template = new ControlTemplate();
        thumb.Height = 20;
        thumb.Width = 20;

        thumb.DragDelta+=thumb_DragDelta;

        canvas.Children.Add(thumb);
        Canvas.SetTop(thumb, 90);
        Canvas.SetLeft(thumb, 90);


        canvas.ManipulationMode = ManipulationModes.All;
        canvas.ManipulationDelta += rec_ManipulationDelta;
        canvas.RenderTransform = new TranslateTransform(); // Create new TranslateTransform and assign to the rectangle

        board.Children.Add(canvas);
    }

    private void thumb_DragDelta(object sender, DragDeltaEventArgs e)
    {
        Thumb thumbSender = (Thumb)sender;

        var p= thumbSender.Parent;


        //double yadjust = recSender.Height + e.VerticalChange;
        //double xadjust = recSender.Width + e.HorizontalChange;

        //if ((xadjust >= 0) && (yadjust >= 0))
        {
            //recSender.Width = xadjust;
            //recSender.Height = yadjust;
            Canvas.SetLeft(thumbSender, Canvas.GetLeft(thumbSender) + e.HorizontalChange);
            Canvas.SetTop(thumbSender, Canvas.GetTop(thumbSender) + e.VerticalChange);

        }
    }

Answer 1

由于您知道 Thumb 的父级是 Canvas，您可以将其转换为 Canvas 类型，然后获取其尺寸。

Canvas parentOfThumb = thumbSender.Parent as Canvas;
if (parentOfThumb != null) //if in case Parent is not canvas
    int p = parentOfThumb.ActualHeight;