using System;/// <summary>
/// 布局方向
/// </summary>
[Flags]
public enum ArrangementDirection
{None = 0,LeftTop = 1,Top = 2,RightTop = 4,Right = 8,RightBottom = 16,Bottom = 32,LeftBottom = 64,Left = 128,All = LeftTop | Top | RightTop | Right | RightBottom | Bottom | LeftBottom | Left,
}

using System;
using System.Windows;/// <summary>
/// 布局变化的事件
/// </summary>
public class ArrangementChangedEventArgs : EventArgs
{public ArrangementChangedEventArgs(Rect oldArrangement, Rect newArrangement){this.OldArrangement = oldArrangement;this.NewArrangement = newArrangement;}/// <summary>/// 旧布局信息/// </summary>public Rect OldArrangement { get; private set; }/// <summary>/// 新布局信息/// </summary>public Rect NewArrangement { get; private set; }
}

using System;/// <summary>
/// 布局方向
/// </summary>
[Flags]
public enum ArrangementDirection
{None = 0,LeftTop = 1,Top = 2,RightTop = 4,Right = 8,RightBottom = 16,Bottom = 32,LeftBottom = 64,Left = 128,All = LeftTop | Top | RightTop | Right | RightBottom | Bottom | LeftBottom | Left,
}

using System;using System.Diagnostics.Contracts;using System.Windows;using System.Windows.Controls;using System.Windows.Controls.Primitives;using System.Windows.Documents;using System.Windows.Input;using System.Windows.Media;using System.Windows.Shapes;/// <summary>/// 布局装饰器/// </summary>public abstract class ArrangementAdorner : Adorner{#region Fields/// <summary>/// 拖动方块的边长/// </summary>private const double ThumbSideLength = 6;/// <summary>/// 可视化对象集合/// </summary>private readonly VisualCollection visualCollection;/// <summary>/// 对齐方向/// </summary>private readonly ArrangementDirection direction;/// <summary>/// 各个方向的拖动方块/// </summary>private readonly Thumb topThumb,leftTopthumb,rightTopThumb,righThumb,rightBottomThumb,bottomThumb,leftBottomThumb,leftThumb;/// <summary>/// 当前位置/// </summary>private Point currentLocation;/// <summary>/// 拖动前的大小/// </summary>private Size oldSize;/// <summary>/// 拖动前左边缘的值/// </summary>private double oldLeft;/// <summary>/// 拖动前上边缘的值/// </summary>private double oldTop;#endregion Fields#region Constructors/// <summary>/// 构造函数/// </summary>/// <param name="adornedElement">装饰器所要绑定到的元素。</param>/// <param name="arrangementDirection">布局方向</param>protected ArrangementAdorner(FrameworkElement adornedElement, ArrangementDirection arrangementDirection = ArrangementDirection.All): base(adornedElement){this.direction = arrangementDirection;this.visualCollection = new VisualCollection(this);this.AddThumbIfNeeded(ref this.leftTopthumb,ArrangementDirection.LeftTop,HorizontalAlignment.Left,VerticalAlignment.Top,Cursors.SizeNWSE);this.AddThumbIfNeeded(ref this.topThumb,ArrangementDirection.Top,HorizontalAlignment.Stretch,VerticalAlignment.Top,Cursors.SizeNS);this.AddThumbIfNeeded(ref this.rightTopThumb,ArrangementDirection.RightTop,HorizontalAlignment.Right,VerticalAlignment.Top,Cursors.SizeNESW);this.AddThumbIfNeeded(ref this.righThumb,ArrangementDirection.Right,HorizontalAlignment.Right,VerticalAlignment.Stretch,Cursors.SizeWE);this.AddThumbIfNeeded(ref this.rightBottomThumb,ArrangementDirection.RightBottom,HorizontalAlignment.Right,VerticalAlignment.Bottom,Cursors.SizeNWSE);this.AddThumbIfNeeded(ref this.bottomThumb,ArrangementDirection.Bottom,HorizontalAlignment.Stretch,VerticalAlignment.Bottom,Cursors.SizeNS);this.AddThumbIfNeeded(ref this.leftBottomThumb,ArrangementDirection.LeftBottom,HorizontalAlignment.Left,VerticalAlignment.Bottom,Cursors.SizeNESW);this.AddThumbIfNeeded(ref this.leftThumb,ArrangementDirection.Left,HorizontalAlignment.Left,VerticalAlignment.Stretch,Cursors.SizeWE);}#endregion Constructorspublic event EventHandler<ArrangementChangedEventArgs> ArrangementChanged;#region Protected Methods#region Overrides/// <summary>/// 获取此元素内的可视化子元素的数目。/// </summary>/// <returns>/// 此元素内的可视化子元素的数目。/// </returns>protected override int VisualChildrenCount{get{return this.visualCollection.Count;}}/// <summary>/// 定位子元素并确定大小。/// </summary>/// <returns>/// 所用的实际大小。/// </returns>/// <param name="finalSize">排列自身及其子元素的最终区域。</param>protected override Size ArrangeOverride(Size finalSize){this.ArrangeThumbIfNeeded(this.leftTopthumb,new Point(-ThumbSideLength, -ThumbSideLength),new Size(ThumbSideLength, ThumbSideLength));this.ArrangeThumbIfNeeded(this.topThumb,new Point(0, -ThumbSideLength),new Size(finalSize.Width, ThumbSideLength));this.ArrangeThumbIfNeeded(this.rightTopThumb,new Point(finalSize.Width, -ThumbSideLength),new Size(ThumbSideLength, ThumbSideLength));this.ArrangeThumbIfNeeded(this.righThumb,new Point(finalSize.Width, 0),new Size(ThumbSideLength, finalSize.Height));this.ArrangeThumbIfNeeded(this.rightBottomThumb,new Point(finalSize.Width, finalSize.Height),new Size(ThumbSideLength, ThumbSideLength));this.ArrangeThumbIfNeeded(this.bottomThumb,new Point(0, finalSize.Height),new Size(finalSize.Width, ThumbSideLength));this.ArrangeThumbIfNeeded(this.leftBottomThumb,new Point(-ThumbSideLength, finalSize.Height),new Size(ThumbSideLength, ThumbSideLength));this.ArrangeThumbIfNeeded(this.leftThumb,new Point(-ThumbSideLength, 0),new Size(ThumbSideLength, finalSize.Height));return base.ArrangeOverride(finalSize);}/// <summary>/// 从子元素集合返回指定索引处的子级。/// </summary>/// <returns>/// 所请求的子元素。它不应返回 null；如果提供的索引超出范围，将引发异常。/// </returns>/// <param name="index">集合中所请求子元素从零开始的索引。</param>protected override Visual GetVisualChild(int index){return this.visualCollection[index];}#endregion Overrides#region Virtuals/// <summary>/// 创建布局方块/// </summary>/// <param name="horizontalAlignment">方块的水平对齐方向</param>/// <param name="verticalAlignment">方块的垂直对齐方向</param>/// <param name="cursor">方块的光标</param>/// <returns>创建好的方块</returns>protected virtual Thumb CreateResizeThumb(HorizontalAlignment horizontalAlignment,VerticalAlignment verticalAlignment,Cursor cursor){var thumb = new Thumb{HorizontalAlignment = horizontalAlignment,VerticalAlignment = verticalAlignment,Cursor = cursor,Template = this.GetResizeThumbControlTemplate()};return thumb;}/// <summary>/// 获取框架元素的位置/// </summary>/// <param name="element">框架元素</param>/// <returns>框架元素所在的位置</returns>protected abstract Point GetLocation(FrameworkElement element);/// <summary>/// 判断框架元素的位置偏移是否合法/// </summary>/// <param name="element">框架元素</param>/// <param name="offset">偏移向量</param>/// <returns>合法返回true,否则返回false</returns>protected virtual bool IsLocationOffsetLegal(FrameworkElement element, Vector offset){var targetLocation = this.currentLocation + offset;if (targetLocation.X < 0){return false;}return true;}/// <summary>/// 设置框架元素的位置/// </summary>/// <param name="element">框架元素</param>/// <param name="location">新位置</param>protected abstract void SetLocation(FrameworkElement element, Point location);/// <summary>/// 获取框架元素的宽度/// </summary>/// <param name="element">框架元素</param>/// <returns>宽度</returns>protected virtual double GetWidth(FrameworkElement element){return element.Width;}/// <summary>/// 获取框架元素的高度/// </summary>/// <param name="element">框架元素</param>/// <returns>高度</returns>protected virtual double GetHeight(FrameworkElement element){return element.Height;}/// <summary>/// 判断框架元素的宽度变化是否合法/// </summary>/// <param name="element">框架元素</param>/// <param name="widthDelta">宽度变化</param>/// <returns>变化是否合法</returns>protected virtual bool IsWidthDeltaLegal(FrameworkElement element, double widthDelta){double newWidth = this.GetWidth(element) + widthDelta;return this.IsInRange(element.MaxWidth, element.MinWidth, newWidth);}/// <summary>/// 判断框架元素的高度变化是否合法/// </summary>/// <param name="element">框架元素</param>/// <param name="heightDelta">高度变化</param>/// <returns>变化是否合法</returns>protected virtual bool IsHeightDeltaLegal(FrameworkElement element, double heightDelta){double newHeight = this.GetHeight(element) + heightDelta;return this.IsInRange(element.MaxHeight, element.MinHeight, newHeight);}/// <summary>/// 设置框架元素的宽度变化/// </summary>/// <param name="element">框架元素</param>/// <param name="widthDelta">宽度变化</param>protected virtual void SetWidthDelta(FrameworkElement element, double widthDelta){element.Width += widthDelta;}/// <summary>/// 设置框架元素的高度变化/// </summary>/// <param name="element">框架元素</param>/// <param name="heightDelta">高度变化</param>protected virtual void SetHeightDelta(FrameworkElement element, double heightDelta){element.Height += heightDelta;}#endregion Virtuals#endregion  Protected Methods#region Private Methods/// <summary>/// 在需要时添加拖动方块/// </summary>/// <param name="thumb">类中对应的方块</param>/// <param name="arrangementDirection">方块对应的布局方向</param>/// <param name="horizontalAlignment">方块的水平对齐方向</param>/// <param name="verticalAlignment">方块的垂直对齐方向</param>/// <param name="cursor">方块的光标</param>private void AddThumbIfNeeded(ref Thumb thumb,ArrangementDirection arrangementDirection,HorizontalAlignment horizontalAlignment,VerticalAlignment verticalAlignment,Cursor cursor){if (this.HasDirectionFlagSet(arrangementDirection)){thumb = this.CreateResizeThumb(horizontalAlignment, verticalAlignment, cursor);thumb.DragStarted += this.ThumbDragStarted;thumb.DragDelta += this.ThumbDragDelta;thumb.DragCompleted += this.ThumbDragCompleted;this.visualCollection.Add(thumb);}}/// <summary>/// 判断布局方向是否被设置/// </summary>/// <param name="arrangementDirection">布局方向</param>/// <returns>被设置返回true,否则返回false</returns>private bool HasDirectionFlagSet(ArrangementDirection arrangementDirection){return (this.direction & arrangementDirection) == arrangementDirection;}/// <summary>/// 获取布局方块的控件模板/// </summary>/// <returns>控件模板</returns>private ControlTemplate GetResizeThumbControlTemplate(){var factory = new FrameworkElementFactory(typeof(Rectangle));factory.SetValue(Shape.FillProperty, Brushes.Transparent);factory.SetValue(Shape.StrokeProperty, Brushes.Transparent);var controlTemplate = new ControlTemplate { TargetType = typeof(Thumb), VisualTree = factory };return controlTemplate;}/// <summary>/// 在需要时定位并确定方块大小/// </summary>/// <param name="thumb">方块</param>/// <param name="location">方块位置</param>/// <param name="size">方块大小</param>private void ArrangeThumbIfNeeded(Thumb thumb, Point location, Size size){if (thumb != null){if (thumb.HorizontalAlignment != HorizontalAlignment.Stretch){thumb.Width = size.Width;}if (thumb.VerticalAlignment != VerticalAlignment.Stretch){thumb.Height = size.Height;}thumb.Arrange(new Rect(location, size));}}/// <summary>/// 判断一个值是否在范围中/// </summary>/// <param name="maximum">最大值,可取</param>/// <param name="minimum">最小值,可取</param>/// <param name="value">值</param>/// <returns>值在范围中返回true,否则返回false</returns>private bool IsInRange(double maximum, double minimum, double value){return (value >= minimum) && (value <= maximum);}#endregion Private Methods#region Events Handler/// <summary>/// 拖动开始的响应/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void ThumbDragStarted(object sender, DragStartedEventArgs e){var frameworkElement = this.AdornedElement as FrameworkElement;this.currentLocation = this.GetLocation(frameworkElement);this.oldLeft = this.currentLocation.X;this.oldTop = this.currentLocation.Y;var width = this.GetWidth(frameworkElement);var height = this.GetHeight(frameworkElement);this.oldSize = new Size(width, height);}/// <summary>/// 拖动变化的响应/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void ThumbDragDelta(object sender, DragDeltaEventArgs e){var frameworkElement = this.AdornedElement as FrameworkElement;var thumb = sender as Thumb;Contract.Assert(thumb != null);switch (thumb.HorizontalAlignment){case HorizontalAlignment.Left:{var offset = new Vector(e.HorizontalChange, 0);if (this.IsLocationOffsetLegal(frameworkElement, offset)){this.currentLocation.Offset(e.HorizontalChange, 0);if (this.IsWidthDeltaLegal(frameworkElement, -e.HorizontalChange)){this.SetWidthDelta(frameworkElement, -e.HorizontalChange);}}break;}case HorizontalAlignment.Right:{if (this.IsWidthDeltaLegal(frameworkElement, e.HorizontalChange)){this.SetWidthDelta(frameworkElement, e.HorizontalChange);}break;}}switch (thumb.VerticalAlignment){case VerticalAlignment.Top:{var offset = new Vector(0, e.VerticalChange);if (this.IsLocationOffsetLegal(frameworkElement, offset)){this.currentLocation.Offset(0, e.VerticalChange);if (this.IsHeightDeltaLegal(frameworkElement, -e.VerticalChange)){this.SetHeightDelta(frameworkElement, -e.VerticalChange);}}break;}case VerticalAlignment.Bottom:{if (this.IsHeightDeltaLegal(frameworkElement, e.VerticalChange)){this.SetHeightDelta(frameworkElement, e.VerticalChange);}break;}}this.SetLocation(frameworkElement, this.currentLocation);}/// <summary>/// 拖动结束的响应/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void ThumbDragCompleted(object sender, DragCompletedEventArgs e){if (this.ArrangementChanged != null){var frameworkElement = this.AdornedElement as FrameworkElement;var oldArrangement = new Rect(new Point(this.oldLeft, this.oldTop), this.oldSize);var newArrangement = new Rect(this.GetLocation(frameworkElement),new Size(this.GetWidth(frameworkElement), this.GetHeight(frameworkElement)));this.ArrangementChanged(this, new ArrangementChangedEventArgs(oldArrangement, newArrangement));}}#endregion Events Handler}

using System.Windows;using System.Windows.Controls;/// <summary>/// 画布布局装饰器/// </summary>public class CanvasArrangementAdorner : ArrangementAdorner{/// <summary>/// 构造函数/// </summary>/// <param name="adornedElement">装饰器所要绑定到的元素。</param>/// <param name="arrangementDirection">布局方向</param>public CanvasArrangementAdorner(FrameworkElement adornedElement, ArrangementDirection arrangementDirection = ArrangementDirection.All): base(adornedElement, arrangementDirection){}#region Overrides of ArrangementAdorner/// <summary>/// 获取框架元素的位置/// </summary>/// <param name="element">框架元素</param>/// <returns>框架元素所在的位置</returns>protected override Point GetLocation(FrameworkElement element){return new Point(Canvas.GetLeft(element), Canvas.GetTop(element));}/// <summary>/// 设置框架元素的位置/// </summary>/// <param name="element">框架元素</param>/// <param name="location">新位置</param>protected override void SetLocation(FrameworkElement element, Point location){Canvas.SetLeft(element, location.X);Canvas.SetTop(element, location.Y);}#endregion}