TeamAAS-2.5/TeamAAS.Base/TeamAAS.FlowEngine/FlowEditor/Controls/DragAdorner.cs

using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Media;

namespace TeamAAS.FlowEditor.Controls
{
    public class DragAdorner : Adorner
    {
        private readonly Border _child;
        private TranslateTransform _transform = new TranslateTransform();

        public DragAdorner(UIElement adornedElement, Border child) : base(adornedElement)
        {
            _child = child;
            _child.Opacity = 0.7;
            _child.IsHitTestVisible = false;
            _child.RenderTransform = _transform;
            AddVisualChild(_child);
        }

        public void SetPosition(double x, double y)
        {
            _transform.X = x;
            _transform.Y = y;
            InvalidateVisual();
        }

        /// <summary>显示/隐藏预览（移出画布时隐藏）</summary>
        public void SetVisible(bool visible)
        {
            _child.Visibility = visible ? Visibility.Visible : Visibility.Collapsed;
        }

        protected override Visual GetVisualChild(int index) => _child;
        protected override int VisualChildrenCount => 1;

        protected override Size MeasureOverride(Size constraint)
        {
            _child.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
            return _child.DesiredSize;
        }

        protected override Size ArrangeOverride(Size finalSize)
        {
            _child.Arrange(new Rect(finalSize));
            return finalSize;
        }

        protected override Geometry GetLayoutClip(Size layoutSlotSize) => null;
    }
}