编写拖动效果装饰器与状态回显装饰器

RazorEngineTest/DropPlacementAdorner.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace RazorEngineTest
+{
+    using System.Windows;
+    using System.Windows.Documents;
+    using System.Windows.Media;
+
+    public class DropPlacementAdorner : Adorner
+    {
+        private readonly string _position;
+        private static readonly Pen _pen;
+
+        static DropPlacementAdorner()
+        {
+            // 定义装饰器的画笔
+            _pen = new Pen(Brushes.Red, 5.0);
+            _pen.Freeze();
+        }
+
+        public DropPlacementAdorner(UIElement adornedElement, string position)
+            : base(adornedElement)
+        {
+            _position = position;
+            IsHitTestVisible = false;
+        }
+
+        protected override void OnRender(DrawingContext drawingContext)
+        {
+            var adornedElementRect = new Rect(AdornedElement.RenderSize);
+
+            // 根据位置信息绘制不同的视觉效果
+            switch (_position)
+            {
+                case "上":
+                    drawingContext.DrawLine(_pen,
+                        new Point(0, 0),
+                        new Point(adornedElementRect.Right, 0));
+                    break;
+                case "下":
+                    drawingContext.DrawLine(_pen,
+                        new Point(0, adornedElementRect.Bottom),
+                        new Point(adornedElementRect.Right, adornedElementRect.Bottom));
+                    break;
+                case "左":
+                    drawingContext.DrawLine(_pen,
+                        new Point(0, 0),
+                        new Point(0, adornedElementRect.Bottom));
+                    break;
+                case "右":
+                    drawingContext.DrawLine(_pen,
+                        new Point(adornedElementRect.Right, 0),
+                        new Point(adornedElementRect.Right, adornedElementRect.Bottom));
+                    break;
+                case "中":
+                    drawingContext.DrawRectangle(null, _pen, adornedElementRect);
+                    break;
+                default:break;
+            }
+        }
+    }
+}