添加项目文件。

Util.DiagramDesigner/Controls/RelativePositionPanel.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media;
+
+namespace Util.DiagramDesigner
+{
+    public class RelativePositionPanel : Panel
+    {
+        public static readonly DependencyProperty RelativePositionProperty =
+            DependencyProperty.RegisterAttached("RelativePosition", typeof(Point), typeof(RelativePositionPanel),
+            new FrameworkPropertyMetadata(new Point(0, 0),
+                                          new PropertyChangedCallback(RelativePositionPanel.OnRelativePositionChanged)));
+
+        public static Point GetRelativePosition(UIElement element)
+        {
+            if (element == null)
+            {
+                throw new ArgumentNullException("element");
+            }
+            return (Point)element.GetValue(RelativePositionProperty);
+        }
+
+        public static void SetRelativePosition(UIElement element, Point value)
+        {
+            if (element == null)
+            {
+                throw new ArgumentNullException("element");
+            }
+            element.SetValue(RelativePositionProperty, value);
+        }
+
+        private static void OnRelativePositionChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            UIElement reference = d as UIElement;
+            if (reference != null)
+            {
+                RelativePositionPanel parent = VisualTreeHelper.GetParent(reference) as RelativePositionPanel;
+                if (parent != null)
+                {
+                    parent.InvalidateArrange();
+                }
+            }
+        }
+
+        protected override Size ArrangeOverride(Size arrangeSize)
+        {
+            foreach (UIElement element in base.InternalChildren)
+            {
+                if (element != null)
+                {
+                    Point relPosition = GetRelativePosition(element);
+                    double x = (arrangeSize.Width - element.DesiredSize.Width) * relPosition.X;
+                    double y = (arrangeSize.Height - element.DesiredSize.Height) * relPosition.Y;
+
+                    if (double.IsNaN(x)) x = 0;
+                    if (double.IsNaN(y)) y = 0;
+
+                    element.Arrange(new Rect(new Point(x, y), element.DesiredSize));
+                }
+            }
+            return arrangeSize;
+        }
+
+        protected override Size MeasureOverride(Size availableSize)
+        {
+            Size size = new Size(double.PositiveInfinity, double.PositiveInfinity);
+
+            // SDK docu says about InternalChildren Property: 'Classes that are derived from Panel 
+            // should use this property, instead of the Children property, for internal overrides 
+            // such as MeasureCore and ArrangeCore.
+
+            foreach (UIElement element in this.InternalChildren)
+            {
+                if (element != null)
+                    element.Measure(size);
+            }
+
+            return base.MeasureOverride(availableSize);
+        }
+    }
+}