refactor<*>: rewrite all codes...

src/Views/Controls/DragDropAdorner.cs

@@ -0,0 +1,80 @@
+using System.Runtime.InteropServices;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Documents;
+using System.Windows.Media;
+
+namespace SourceGit.Views.Controls {
+
+    /// <summary>
+    ///     DragDropAdorner容器
+    /// </summary>
+    public class DragDropAdornerLayer : Grid {
+        private static AdornerLayer host = null;
+        private static bool enableFeedback = false;
+
+        public DragDropAdornerLayer() {
+            Loaded += (o, e) => host = AdornerLayer.GetAdornerLayer(this);
+            PreviewGiveFeedback += OnPreviewGiveFeedback;
+        }
+
+        public static void Add(Adorner adorner) {
+            host.Add(adorner);
+            enableFeedback = true;
+        }
+
+        public static void Remove(Adorner adorner) {
+            host.Remove(adorner);
+            enableFeedback = false;
+        }
+
+        private static void OnPreviewGiveFeedback(object sender, GiveFeedbackEventArgs e) {
+            if (enableFeedback) host.Update();
+            e.Handled = true;
+        }
+    }
+
+    /// <summary>
+    ///     展示正在拖拽的视图
+    /// </summary>
+    public class DragDropAdorner : Adorner {
+        private Size renderSize;
+        private Brush renderBrush;
+
+        public struct PInPoint {
+            public int X;
+            public int Y;
+
+            public PInPoint(int x, int y) { X = x; Y = y; }
+            public PInPoint(double x, double y) { X = (int)x; Y = (int)y; }
+        }
+
+        [DllImport("user32.dll")]
+        static extern void GetCursorPos(ref PInPoint p);
+
+        public DragDropAdorner(FrameworkElement elem) : base(elem) {
+            renderSize = elem.RenderSize;
+            renderBrush = new VisualBrush(elem);
+            IsHitTestVisible = false;
+            DragDropAdornerLayer.Add(this);
+        }
+
+        public void Remove() {
+            DragDropAdornerLayer.Remove(this);
+        }
+
+        protected override void OnRender(DrawingContext dc) {
+            base.OnRender(dc);
+
+            PInPoint p = new PInPoint();
+            GetCursorPos(ref p);
+
+            Point pos = PointFromScreen(new Point(p.X, p.Y));
+            Rect rect = new Rect(pos.X, pos.Y, renderSize.Width, renderSize.Height);
+
+            dc.PushOpacity(1);
+            dc.DrawRectangle(renderBrush, null, rect);
+            dc.DrawRectangle(null, new Pen(Brushes.DeepSkyBlue, 2), rect);
+        }
+    }
+}