前言：
很多时候我们需要在运行时，动态地改变控件的位置以及大小，以获得更好的布局。比如说实际项目中的可自定义的报表、可自定义的单据等诸如此类。它们有个特点就是允许客户或者二次开发人员设计它们需要的界面设置功能。
本人以前也做过可自定义系统，包括界面和功能，主要为了减少开发人员的工作量以及程序的灵活性和健壮性。
本篇主要讨论下，在运行时如何实现拖拉控件，达到改变控件位置与大小。功能将模拟VS设计界面时的拖拉功能。
(本篇暂不涉及多控件同时操作)
一、技术概述
其实实现运行时控件的拖拉并不难，主要是改变控件的Location与Size即可。动态调整时再捕获MouseDown、MouseMove及MouseUp事件来实时修改上述两个属性就可以实现。
二、功能规划
在此之前，我们先来看下.net设计界面，一旦选中某个控件时，将会出现如下图的边框：
之后就可以通过拖拉出现的边框改变其大小。而改变控件的位置，实际上是当鼠标点击在控件内部拖动时实现的。
所有本例也将功能分为两个部分实现，分别为控件内部拖动改变位置与控件边框拖拉改变大小。
三、具体实现
1.拖动控件改变位置
首先，新建一个项目，然后添加一个类，取名叫MoveControl，该类用来给控件挂载事件实现拖动。
接着在该类中添加字段currentControl，用来保存需要操作的控件，即通过构造函数传递的控件。
接着创建一方法--AddEvents,用来给当前的控件挂载事件。
代码如下：
DragControl
1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.Text;4 usingSystem.Windows.Forms;5 usingSystem.Drawing;6
7 namespaceDragControl8 {9 public classMoveControl10 {11 #region Constructors
12 publicMoveControl(Control ctrl)13 {14 currentControl =ctrl;15 AddEvents();16 }17 #endregion
18
19 #region Fields
20 private Control currentControl; //传入的控件
21 #endregion
22
23 #region Properties
24
25 #endregion
26
27 #region Methods
28 ///
29 ///挂载事件30 ///
31 private voidAddEvents()32 {33 currentControl.MouseClick += newMouseEventHandler(MouseClick);34 currentControl.MouseDown += newMouseEventHandler(MouseDown);35 currentControl.MouseMove += newMouseEventHandler(MouseMove);36 currentControl.MouseUp += newMouseEventHandler(MouseUp);37 }38 #endregion
39
40 #region Events
41 ///
42 ///鼠标单击事件：用来显示边框43 ///
44 ///
45 ///
46 void MouseClick(objectsender, MouseEventArgs e)47 {48 }49
50 ///
51 ///鼠标按下事件：记录当前鼠标相对窗体的坐标52 ///
53 void MouseDown(objectsender, MouseEventArgs e)54 {55
56 }57
58 ///
59 ///鼠标移动事件：让控件跟着鼠标移动60 ///
61 void MouseMove(objectsender, MouseEventArgs e)62 {63 }64
65 ///
66 ///鼠标弹起事件：让自定义的边框出现67 ///
68 void MouseUp(objectsender, MouseEventArgs e)69 {70 }71 #endregion
72 }73 }
接着我们需要实现MouseDown、MouseMove、MouseUp三个事件。
不过在此之前，我们必须要弄清楚，移动即表示坐标的改变，所以必定要有个起始坐标和终点坐标。
所以我们在MoveControl类中加入两个字段。
private Point pPoint; //上个鼠标坐标
private Point cPoint; //当前鼠标坐标
而且在开始拖动之前，我们肯定需要先单击一次控件。在MouseDown时获取当前光标的位置，保存到pPoint中。
(此处用Cursor获得坐标的好处，就是忽略掉容器的麻烦问题)
1 ///
2 ///鼠标单击事件：用来显示边框3 ///
4 void MouseClick(objectsender, MouseEventArgs e)5 {6 pPoint =Cursor.Position;7 }
接着便实现MouseMove的事件，当鼠标左键按下时，接着移动鼠标后，继续鼠标移动后的坐标，然后与MouseDown时记下的坐标相减，就得到鼠标的位移值，接着控件的Location加上该位移值即可，然后更新pPoint。
1 ///
2 ///鼠标移动事件：让控件跟着鼠标移动3 ///
4 void MouseMove(objectsender, MouseEventArgs e)5 {6 Cursor.Current = Cursors.SizeAll; //当鼠标处于控件内部时，显示光标样式为SizeAll7 //当鼠标左键按下时才触发
8 if (e.Button ==MouseButtons.Left)9 {10 cPoint = Cursor.Position; //获得当前鼠标位置
11 int x = cPoint.X -pPoint.X;12 int y = cPoint.Y -pPoint.Y;13 currentControl.Location = new Point(currentControl.Location.X + x, currentControl.Location.Y +y);14 pPoint =cPoint;15 }16 }
由于此时还没涉及到边框，所以MouseUp暂时不用处理。至此拖动的基本功能已经实现！
目前MoveControl的完整代码如下：
MoveControl
1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.Text;4 usingSystem.Windows.Forms;5 usingSystem.Drawing;6
7 namespaceDragControl8 {9 public classMoveControl10 {11 #region Constructors
12 publicMoveControl(Control ctrl)13 {14 currentControl =ctrl;15 AddEvents();16 }17 #endregion
18
19 #region Fields
20 private Control currentControl; //传入的控件
21 private Point pPoint; //上个鼠标坐标
22 private Point cPoint; //当前鼠标坐标
23 #endregion
24
25 #region Properties
26
27 #endregion
28
29 #region Methods
30 ///
31 ///挂载事件32 ///
33 private voidAddEvents()34 {35 currentControl.MouseDown += newMouseEventHandler(MouseDown);36 currentControl.MouseMove += newMouseEventHandler(MouseMove);37 currentControl.MouseUp += newMouseEventHandler(MouseUp);38 }39
40 ///
41 ///绘制拖拉时的黑色边框42 ///
43 public static voidDrawDragBound(Control ctrl)44 {45 ctrl.Refresh();46 Graphics g =ctrl.CreateGraphics();47 int width =ctrl.Width;48 int height =ctrl.Height;49 Point[] ps = new Point[5]{new Point(0,0),new Point(width -1,0),50 new Point(width -1,height -1),new Point(0,height-1),new Point(0,0)};51 g.DrawLines(newPen(Color.Black), ps);52 }53 #endregion
54
55 #region Events
56 ///
57 ///鼠标按下事件：记录当前鼠标相对窗体的坐标58 ///
59 void MouseDown(objectsender, MouseEventArgs e)60 {61 pPoint =Cursor.Position;62 }63
64 ///
65 ///鼠标移动事件：让控件跟着鼠标移动66 ///
67 void MouseMove(objectsender, MouseEventArgs e)68 {69 Cursor.Current = Cursors.SizeAll; //当鼠标处于控件内部时，显示光标样式为SizeAll70 //当鼠标左键按下时才触发
71 if (e.Button ==MouseButtons.Left)72 {73 MoveControl.DrawDragBound(this.currentControl);74 cPoint = Cursor.Position; //获得当前鼠标位置
75 int x = cPoint.X -pPoint.X;76 int y = cPoint.Y -pPoint.Y;77 currentControl.Location = new Point(currentControl.Location.X + x, currentControl.Location.Y +y);78 pPoint =cPoint;79 }80 }81
82 ///
83 ///鼠标弹起事件：让自定义的边框出现84 ///
85 void MouseUp(objectsender, MouseEventArgs e)86 {87 this.currentControl.Refresh();88 }89 #endregion
90 }91 }
下面我们来测试下拖动的功能。
创建一个Form窗体，可以再界面上添加你要测试的控件类型，此处我只用TextBox左下测试。在Load的中添加以下代码，将Form中的所有控件挂载上拖拉功能。
1 private void Form1_Load(objectsender, EventArgs e)2 {3 foreach (Control ctrl in this.Controls)4 {5 newMoveControl(ctrl);6 }7 }
此时，有心人可能会发现VS中拖动控件时，将会出现黑色边框，而处于没有。
这也很简单，我们在MouseMove时加上如下代码即可。
1 ///
2 ///绘制拖拉时的黑色边框3 ///
4 public static voidDrawDragBound(Control ctrl)5 {6 ctrl.Refresh();7 Graphics g =ctrl.CreateGraphics();8 int width =ctrl.Width;9 int height =ctrl.Height;10 Point[] ps = new Point[5]{new Point(0,0),new Point(width -1,0),11 new Point(width -1,height -1),new Point(0,height-1),new Point(0,0)};12 g.DrawLines(newPen(Color.Black), ps);13 }14
15
16 ///
17 ///鼠标移动事件：让控件跟着鼠标移动18 ///
19 void MouseMove(objectsender, MouseEventArgs e)20 {21 Cursor.Current = Cursors.SizeAll; //当鼠标处于控件内部时，显示光标样式为SizeAll22 //当鼠标左键按下时才触发
23 if (e.Button ==MouseButtons.Left)24 {25 MoveControl.DrawDragBound(this.currentControl);26 cPoint = Cursor.Position; //获得当前鼠标位置
27 int x = cPoint.X -pPoint.X;28 int y = cPoint.Y -pPoint.Y;29 currentControl.Location = new Point(currentControl.Location.X + x, currentControl.Location.Y +y);30 pPoint =cPoint;31 }32 }
同时要在MoveUp的时候，刷新一下自己，让黑色边框消失掉！
1 ///
2 ///鼠标弹起事件：让自定义的边框出现3 ///
4 void MouseUp(objectsender, MouseEventArgs e)5 {6 this.currentControl.Refresh();7 }
接着用没有边框的控件测试下就会很明显。如下图所示：
2.通过边框拖拉控件改变大小
此处的主要思路为：点击控件的时候，创建一个自定义的用户控件，该用户控件响应区域就是传入控件的边框区域，同时给它画上虚线与8个小圆圈。
第一、创建用户控件--FrameControl(边框控件)，然后增加一个字段用来保存传入的控件，还有加载事件，此处类同前面的MoveControl。
FrameControl
1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.ComponentModel;4 usingSystem.Drawing;5 usingSystem.Data;6 usingSystem.Linq;7 usingSystem.Text;8 usingSystem.Windows.Forms;9
10 namespaceDragControl11 {12 public partial classFrameControl : UserControl13 {14 #region Constructors
15 publicFrameControl(Control ctrl)16 {17 baseControl =ctrl;18 AddEvents();19 }20 #endregion
21
22 #region Fields
23 Control baseControl; //基础控件，即被包围的控件
24 #endregion
25
26 #region Methods
27 ///
28 ///加载事件29 ///
30 private voidAddEvents()31 {32 this.Name = "FrameControl" +baseControl.Name;33 this.MouseDown += newMouseEventHandler(FrameControl_MouseDown);34 this.MouseMove += newMouseEventHandler(FrameControl_MouseMove);35 this.MouseUp += newMouseEventHandler(FrameControl_MouseUp);36 }37
38 #endregion
39
40 #region Events
41 ///
42 ///鼠标按下事件：记录当前鼠标相对窗体的坐标43 ///
44 void FrameControl_MouseDown(objectsender, MouseEventArgs e)45 {46
47 }48
49 ///
50 ///鼠标移动事件：让控件跟着鼠标移动51 ///
52 void FrameControl_MouseMove(objectsender, MouseEventArgs e)53 {54
55 }56
57 ///
58 ///鼠标弹起事件：让自定义的边框出现59 ///
60 void FrameControl_MouseUp(objectsender, MouseEventArgs e)61 {62
63 }64 #endregion
65 }66 }
做完这些准备工作后，将到了主要的部分，就是给控件画边框。
整个边框分为三个部分：四边框(用来设置可视区域与区域)+四条虚线(只用来显示)+八个小圆圈(用来斜角拖拉)。
所以要建立三个字段，用来分别保存这个数据。
Rectangle[] smallRects = new Rectangle[8];//边框中的八个小圆圈
Rectangle[] sideRects = new Rectangle[4];//四条边框，用来做响应区域
Point[] linePoints = new Point[5];//四条边，用于画虚线
接着就是创建用户控件的可视区域，和上面的三个变量数值。
(以下计算位置的代码，有兴趣的人可以研究下，没有的就直接Copy)
创建边框
1 #region 创建边框
2 ///
3 ///建立控件可视区域4 ///
5 private voidCreateBounds()6 {7 //创建边界
8 int X = baseControl.Bounds.X - square.Width - 1;9 int Y = baseControl.Bounds.Y - square.Height - 1;10 int Height = baseControl.Bounds.Height + (square.Height * 2) + 2;11 int Width = baseControl.Bounds.Width + (square.Width * 2) + 2;12 this.Bounds = newRectangle(X, Y, Width, Height);13 this.BringToFront();14 SetRectangles();15 //设置可视区域
16 this.Region = newRegion(BuildFrame());17 g = this.CreateGraphics();18 }19
20 ///
21 ///设置定义8个小矩形的范围22 ///
23 voidSetRectangles()24 {25 //左上
26 smallRects[0] = new Rectangle(new Point(0, 0), square);27 //右上
28 smallRects[1] = new Rectangle(new Point(this.Width - square.Width - 1, 0), square);29 //左下
30 smallRects[2] = new Rectangle(new Point(0, this.Height - square.Height - 1), square);31 //右下
32 smallRects[3] = new Rectangle(new Point(this.Width - square.Width - 1, this.Height - square.Height - 1), square);33 //上中
34 smallRects[4] = new Rectangle(new Point(this.Width / 2 - 1, 0), square);35 //下中
36 smallRects[5] = new Rectangle(new Point(this.Width / 2 - 1, this.Height - square.Height - 1), square);37 //左中
38 smallRects[6] = new Rectangle(new Point(0, this.Height / 2 - 1), square);39 //右中
40 smallRects[7] = new Rectangle(new Point(square.Width + baseControl.Width + 1, this.Height / 2 - 1), square);41
42 //四条边线43 //左上
44 linePoints[0] = new Point(square.Width / 2, square.Height / 2);45 //右上
46 linePoints[1] = new Point(this.Width - square.Width / 2 - 1, square.Height / 2);47 //右下
48 linePoints[2] = new Point(this.Width - square.Width / 2 - 1, this.Height - square.Height / 2);49 //左下
50 linePoints[3] = new Point(square.Width / 2, this.Height - square.Height / 2 - 1);51 //左上
52 linePoints[4] = new Point(square.Width / 2, square.Height / 2);53
54 //整个包括周围边框的范围
55 ControlRect = new Rectangle(new Point(0, 0), this.Bounds.Size);56 }57
58 ///
59 ///设置边框控件可视区域60 ///
61 ///
62 privateGraphicsPath BuildFrame()63 {64 GraphicsPath path = newGraphicsPath();65 //上边框
66 sideRects[0] = new Rectangle(0, 0, this.Width - square.Width - 1, square.Height + 1);67 //左边框
68 sideRects[1] = new Rectangle(0, square.Height + 1, square.Width + 1, this.Height - square.Height - 1);69 //下边框
70 sideRects[2] = new Rectangle(square.Width + 1, this.Height - square.Height - 1, this.Width - square.Width - 1, square.Height + 1);71 //右边框
72 sideRects[3] = new Rectangle(this.Width - square.Width - 1, 0, square.Width + 1, this.Height - square.Height - 1);73
74 path.AddRectangle(sideRects[0]);75 path.AddRectangle(sideRects[1]);76 path.AddRectangle(sideRects[2]);77 path.AddRectangle(sideRects[3]);78 returnpath;79 }80 #endregion
设置完位置后，接着就是绘制的工作。增加一个Draw的方法用来画，同时设置为Public。此处不用控件的Paint，而是让用户调用，只因为这样方便在不同控件之间切换，也就是一个容器中，只有当前控件有边框。
1 ///
2 ///绘图3 ///
4 public voidDraw()5 {6 this.BringToFront();7 Pen pen = newPen(Color.Black);8 pen.DashStyle = DashStyle.Dot;//设置为虚线,用虚线画四边，模拟微软效果
9 g.DrawLines(pen, linePoints);//绘制四条边线
10 g.FillRectangles(Brushes.White, smallRects); //填充8个小矩形的内部
11 foreach (Rectangle smallRect insmallRects)12 {13 g.DrawEllipse(Pens.Black, smallRect); //绘制8个小椭圆
14 }15 //g.DrawRectangles(Pens.Black, smallRects);//绘制8个小矩形的黑色边线
16 }
做到这里，我们可以去前台看一下效果，不过再此之前，我们需要调用该用户控件。
调用的地方就是在控件上点击的时候，所以在MoveControl中加入MouseClick的事件。
1 ///
2 ///鼠标单击事件：用来显示边框3 ///
4 ///
5 ///
6 protected void MouseClick(objectsender, MouseEventArgs e)7 {8 this.currentControl.Parent.Refresh();//刷新父容器，清除掉其他控件的边框
9 this.currentControl.BringToFront();10 fc = new FrameControl(this.currentControl);11 this.currentControl.Parent.Controls.Add(fc);12 fc.Visible = true;13 fc.Draw();14 }
这时有了边框之后会有一个小问题，就是拖动控件的时候，控件移动了，但是边框还留在原地。
所以，这里需要注意的，就是移动的时候，将边框控件隐藏掉，当MouseUp的时候再显示。
此时的完整代码如下：
MoveControl
1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.Text;4 usingSystem.Windows.Forms;5 usingSystem.Drawing;6
7 namespaceDragControl8 {9 public classMoveControl10 {11 #region Constructors
12 publicMoveControl(Control ctrl)13 {14 currentControl =ctrl;15 AddEvents();16 }17 #endregion
18
19 #region Fields
20 private Control currentControl; //传入的控件
21 private Point pPoint; //上个鼠标坐标
22 private Point cPoint; //当前鼠标坐标
23 FrameControl fc;//边框控件
24 #endregion
25
26 #region Properties
27
28 #endregion
29
30 #region Methods
31 ///
32 ///挂载事件33 ///
34 private voidAddEvents()35 {36 currentControl.MouseClick += newMouseEventHandler(MouseClick);37 currentControl.MouseDown += newMouseEventHandler(MouseDown);38 currentControl.MouseMove += newMouseEventHandler(MouseMove);39 currentControl.MouseUp += newMouseEventHandler(MouseUp);40 }41
42 ///
43 ///绘制拖拉时的黑色边框44 ///
45 public static voidDrawDragBound(Control ctrl)46 {47 ctrl.Refresh();48 Graphics g =ctrl.CreateGraphics();49 int width =ctrl.Width;50 int height =ctrl.Height;51 Point[] ps = new Point[5]{new Point(0,0),new Point(width -1,0),52 new Point(width -1,height -1),new Point(0,height-1),new Point(0,0)};53 g.DrawLines(newPen(Color.Black), ps);54 }55 #endregion
56
57 #region Events
58 ///
59 ///鼠标单击事件：用来显示边框60 ///
61 ///
62 ///
63 protected void MouseClick(objectsender, MouseEventArgs e)64 {65 this.currentControl.Parent.Refresh();//刷新父容器，清除掉其他控件的边框
66 this.currentControl.BringToFront();67 fc = new FrameControl(this.currentControl);68 this.currentControl.Parent.Controls.Add(fc);69 fc.Visible = true;70 fc.Draw();71 }72
73 ///
74 ///鼠标按下事件：记录当前鼠标相对窗体的坐标75 ///
76 void MouseDown(objectsender, MouseEventArgs e)77 {78 pPoint =Cursor.Position;79 }80
81 ///
82 ///鼠标移动事件：让控件跟着鼠标移动83 ///
84 void MouseMove(objectsender, MouseEventArgs e)85 {86 Cursor.Current = Cursors.SizeAll; //当鼠标处于控件内部时，显示光标样式为SizeAll87 //当鼠标左键按下时才触发
88 if (e.Button ==MouseButtons.Left)89 {90 MoveControl.DrawDragBound(this.currentControl);91 if (fc != null) fc.Visible = false; //先隐藏
92 cPoint = Cursor.Position; //获得当前鼠标位置
93 int x = cPoint.X -pPoint.X;94 int y = cPoint.Y -pPoint.Y;95 currentControl.Location = new Point(currentControl.Location.X + x, currentControl.Location.Y +y);96 pPoint =cPoint;97 }98 }99
100 ///
101 ///鼠标弹起事件：让自定义的边框出现102 ///
103 void MouseUp(objectsender, MouseEventArgs e)104 {105 this.currentControl.Refresh();106 if (fc != null)107 {108 fc.Visible = true;109 fc.Draw();110 }111 }112 #endregion
113 }114 }
FrameControl
1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.ComponentModel;4 usingSystem.Drawing;5 usingSystem.Data;6 usingSystem.Text;7 usingSystem.Windows.Forms;8 usingSystem.Drawing.Drawing2D;9
10 namespaceDragControl11 {12 public partial classFrameControl : UserControl13 {14 #region Constructors
15 publicFrameControl(Control ctrl)16 {17 baseControl =ctrl;18 AddEvents();19 CreateBounds();20 }21 #endregion
22
23 #region Fields
24 const int Band = 6; //调整大小的响应边框
25 Size square = new Size(Band, Band);//小矩形大小
26 Control baseControl; //基础控件，即被包围的控件
27 Rectangle[] smallRects = new Rectangle[8];//边框中的八个小圆圈
28 Rectangle[] sideRects = new Rectangle[4];//四条边框，用来做响应区域
29 Point[] linePoints = new Point[5];//四条边，用于画虚线
30 Graphics g; //画图板
31 Rectangle ControlRect; //控件包含边框的区域
32 #endregion
33
34 #region Methods
35 ///
36 ///加载事件37 ///
38 private voidAddEvents()39 {40 this.Name = "FrameControl" +baseControl.Name;41 this.MouseDown += newMouseEventHandler(FrameControl_MouseDown);42 this.MouseMove += newMouseEventHandler(FrameControl_MouseMove);43 this.MouseUp += newMouseEventHandler(FrameControl_MouseUp);44 }45
46 #region 创建边框
47 ///
48 ///建立控件可视区域49 ///
50 private voidCreateBounds()51 {52 //创建边界
53 int X = baseControl.Bounds.X - square.Width - 1;54 int Y = baseControl.Bounds.Y - square.Height - 1;55 int Height = baseControl.Bounds.Height + (square.Height * 2) + 2;56 int Width = baseControl.Bounds.Width + (square.Width * 2) + 2;57 this.Bounds = newRectangle(X, Y, Width, Height);58 this.BringToFront();59 SetRectangles();60 //设置可视区域
61 this.Region = newRegion(BuildFrame());62 g = this.CreateGraphics();63 }64
65 ///
66 ///设置定义8个小矩形的范围67 ///
68 voidSetRectangles()69 {70 //左上
71 smallRects[0] = new Rectangle(new Point(0, 0), square);72 //右上
73 smallRects[1] = new Rectangle(new Point(this.Width - square.Width - 1, 0), square);74 //左下
75 smallRects[2] = new Rectangle(new Point(0, this.Height - square.Height - 1), square);76 //右下
77 smallRects[3] = new Rectangle(new Point(this.Width - square.Width - 1, this.Height - square.Height - 1), square);78 //上中
79 smallRects[4] = new Rectangle(new Point(this.Width / 2 - 1, 0), square);80 //下中
81 smallRects[5] = new Rectangle(new Point(this.Width / 2 - 1, this.Height - square.Height - 1), square);82 //左中
83 smallRects[6] = new Rectangle(new Point(0, this.Height / 2 - 1), square);84 //右中
85 smallRects[7] = new Rectangle(new Point(square.Width + baseControl.Width + 1, this.Height / 2 - 1), square);86
87 //四条边线88 //左上
89 linePoints[0] = new Point(square.Width / 2, square.Height / 2);90 //右上
91 linePoints[1] = new Point(this.Width - square.Width / 2 - 1, square.Height / 2);92 //右下
93 linePoints[2] = new Point(this.Width - square.Width / 2 - 1, this.Height - square.Height / 2);94 //左下
95 linePoints[3] = new Point(square.Width / 2, this.Height - square.Height / 2 - 1);96 //左上
97 linePoints[4] = new Point(square.Width / 2, square.Height / 2);98
99 //整个包括周围边框的范围
100 ControlRect = new Rectangle(new Point(0, 0), this.Bounds.Size);101 }102
103 ///
104 ///设置边框控件可视区域105 ///
106 ///
107 privateGraphicsPath BuildFrame()108 {109 GraphicsPath path = newGraphicsPath();110 //上边框
111 sideRects[0] = new Rectangle(0, 0, this.Width - square.Width - 1, square.Height + 1);112 //左边框
113 sideRects[1] = new Rectangle(0, square.Height + 1, square.Width + 1, this.Height - square.Height - 1);114 //下边框
115 sideRects[2] = new Rectangle(square.Width + 1, this.Height - square.Height - 1, this.Width - square.Width - 1, square.Height + 1);116 //右边框
117 sideRects[3] = new Rectangle(this.Width - square.Width - 1, 0, square.Width + 1, this.Height - square.Height - 1);118
119 path.AddRectangle(sideRects[0]);120 path.AddRectangle(sideRects[1]);121 path.AddRectangle(sideRects[2]);122 path.AddRectangle(sideRects[3]);123 returnpath;124 }125 #endregion
126
127 ///
128 ///绘图129 ///
130 public voidDraw()131 {132 this.BringToFront();133 Pen pen = newPen(Color.Black);134 pen.DashStyle = DashStyle.Dot;//设置为虚线,用虚线画四边，模拟微软效果
135 g.DrawLines(pen, linePoints);//绘制四条边线
136 g.FillRectangles(Brushes.White, smallRects); //填充8个小矩形的内部
137 foreach (Rectangle smallRect insmallRects)138 {139 g.DrawEllipse(Pens.Black, smallRect); //绘制8个小椭圆
140 }141 //g.DrawRectangles(Pens.Black, smallRects);//绘制8个小矩形的黑色边线
142 }143
144 #endregion
145
146 #region Events
147 ///
148 ///鼠标按下事件：记录当前鼠标相对窗体的坐标149 ///
150 void FrameControl_MouseDown(objectsender, MouseEventArgs e)151 {152
153 }154
155 ///
156 ///鼠标移动事件：让控件跟着鼠标移动157 ///
158 void FrameControl_MouseMove(objectsender, MouseEventArgs e)159 {160
161 }162
163 ///
164 ///鼠标弹起事件：让自定义的边框出现165 ///
166 void FrameControl_MouseUp(objectsender, MouseEventArgs e)167 {168
169 }170 #endregion
171 }172 }
测试界面：
到目前为止，还只是有边框，下面将实现拖拉功能。
首先来实现，当鼠标放在响应区域的时候，根据不同的位置显示不同的箭头样子。
为此先创建一个枚举，用来记录当前鼠标的位置，等拖拉的时候根据该枚举值做不同的计算。
1 ///
2 ///鼠标在控件中位置3 ///
4 enumMousePosOnCtrl5 {6 NONE = 0,7 TOP = 1,8 RIGHT = 2,9 BOTTOM = 3,10 LEFT = 4,11 TOPLEFT = 5,12 TOPRIGHT = 6,13 BOTTOMLEFT = 7,14 BOTTOMRIGHT = 8,15 }
创建一个方法，用来改变光标的样子以及枚举值
1 ///
2 ///设置光标状态3 ///
4 public bool SetCursorShape(int x, inty)5 {6 Point point = newPoint(x, y);7 if (!ControlRect.Contains(point))8 {9 Cursor.Current =Cursors.Arrow;10 return false;11 }12 else if (smallRects[0].Contains(point))13 {14 Cursor.Current =Cursors.SizeNWSE;15 mpoc =MousePosOnCtrl.TOPLEFT;16 }17 else if (smallRects[1].Contains(point))18 {19 Cursor.Current =Cursors.SizeNESW;20 mpoc =MousePosOnCtrl.TOPRIGHT;21 }22 else if (smallRects[2].Contains(point))23 {24 Cursor.Current =Cursors.SizeNESW;25 mpoc =MousePosOnCtrl.BOTTOMLEFT;26 }27 else if (smallRects[3].Contains(point))28 {29 Cursor.Current =Cursors.SizeNWSE;30 mpoc =MousePosOnCtrl.BOTTOMRIGHT;31 }32 else if (sideRects[0].Contains(point))33 {34 Cursor.Current =Cursors.SizeNS;35 mpoc =MousePosOnCtrl.TOP;36 }37 else if (sideRects[1].Contains(point))38 {39 Cursor.Current =Cursors.SizeWE;40 mpoc =MousePosOnCtrl.LEFT;41 }42 else if (sideRects[2].Contains(point))43 {44 Cursor.Current =Cursors.SizeNS;45 mpoc =MousePosOnCtrl.BOTTOM;46 }47 else if (sideRects[3].Contains(point))48 {49 Cursor.Current =Cursors.SizeWE;50 mpoc =MousePosOnCtrl.RIGHT;51 }52 else
53 {54 Cursor.Current =Cursors.Arrow;55 }56 return true;57 }
接着就是处理相关的三大事件MouseDown、MouseMove、MouseUp来实现拖拉。如同MoveControl都要增加以下两个字段。
private Point pPoint; //上个鼠标坐标
private Point cPoint; //当前鼠标坐标
1 ///
2 ///鼠标按下事件：记录当前鼠标相对窗体的坐标3 ///
4 void FrameControl_MouseDown(objectsender, MouseEventArgs e)5 {6 pPoint =Cursor.Position;7 }8
9 ///
10 ///鼠标移动事件：让控件跟着鼠标移动11 ///
12 void FrameControl_MouseMove(objectsender, MouseEventArgs e)13 {14 if (e.Button ==MouseButtons.Left)15 {16 this.Visible = false;17 MoveControl.DrawDragBound(baseControl);18 ControlMove();19 }20 else
21 {22 this.Visible = true;23 SetCursorShape(e.X, e.Y); //更新鼠标指针样式
24 }25 }26
27 ///
28 ///鼠标弹起事件：让自定义的边框出现29 ///
30 void FrameControl_MouseUp(objectsender, MouseEventArgs e)31 {32 this.baseControl.Refresh(); //刷掉黑色边框
33 this.Visible = true;34 CreateBounds();35 Draw();36 }
在上面的MouseMove中多了一个方法--ControlMove，这个就是根据不同的枚举值，计算控件的移动方式和大小的方法。该方法中同时对控件的最小宽度和高度做了处理。添加如下两个字段。
private int MinWidth = 20; //最小宽度
private int MinHeight = 20;//最小高度
1 ///
2 ///控件移动3 ///
4 private voidControlMove()5 {6 cPoint =Cursor.Position;7 int x = cPoint.X -pPoint.X;8 int y = cPoint.Y -pPoint.Y;9 switch (this.mpoc)10 {11 caseMousePosOnCtrl.TOP:12 if (baseControl.Height - y >MinHeight)13 {14 baseControl.Top +=y;15 baseControl.Height -=y;16 }17 else
18 {19 baseControl.Top -= MinHeight -baseControl.Height;20 baseControl.Height =MinHeight;21 }22 break;23 caseMousePosOnCtrl.BOTTOM:24 if (baseControl.Height + y >MinHeight)25 {26 baseControl.Height +=y;27 }28 else
29 {30 baseControl.Height =MinHeight;31 }32 break;33 caseMousePosOnCtrl.LEFT:34 if (baseControl.Width - x >MinWidth)35 {36 baseControl.Left +=x;37 baseControl.Width -=x;38 }39 else
40 {41 baseControl.Left -= MinWidth -baseControl.Width;42 baseControl.Width =MinWidth;43 }44
45 break;46 caseMousePosOnCtrl.RIGHT:47 if (baseControl.Width + x >MinWidth)48 {49 baseControl.Width +=x;50 }51 else
52 {53 baseControl.Width =MinWidth;54 }55 break;56 caseMousePosOnCtrl.TOPLEFT:57 if (baseControl.Height - y >MinHeight)58 {59 baseControl.Top +=y;60 baseControl.Height -=y;61 }62 else
63 {64 baseControl.Top -= MinHeight -baseControl.Height;65 baseControl.Height =MinHeight;66 }67 if (baseControl.Width - x >MinWidth)68 {69 baseControl.Left +=x;70 baseControl.Width -=x;71 }72 else
73 {74 baseControl.Left -= MinWidth -baseControl.Width;75 baseControl.Width =MinWidth;76 }77 break;78 caseMousePosOnCtrl.TOPRIGHT:79 if (baseControl.Height - y >MinHeight)80 {81 baseControl.Top +=y;82 baseControl.Height -=y;83 }84 else
85 {86 baseControl.Top -= MinHeight -baseControl.Height;87 baseControl.Height =MinHeight;88 }89 if (baseControl.Width + x >MinWidth)90 {91 baseControl.Width +=x;92 }93 else
94 {95 baseControl.Width =MinWidth;96 }97 break;98 caseMousePosOnCtrl.BOTTOMLEFT:99 if (baseControl.Height + y >MinHeight)100 {101 baseControl.Height +=y;102 }103 else
104 {105 baseControl.Height =MinHeight;106 }107 if (baseControl.Width - x >MinWidth)108 {109 baseControl.Left +=x;110 baseControl.Width -=x;111 }112 else
113 {114 baseControl.Left -= MinWidth -baseControl.Width;115 baseControl.Width =MinWidth;116 }117 break;118 caseMousePosOnCtrl.BOTTOMRIGHT:119 if (baseControl.Height + y >MinHeight)120 {121 baseControl.Height +=y;122 }123 else
124 {125 baseControl.Height =MinHeight;126 }127 if (baseControl.Width + x >MinWidth)128 {129 baseControl.Width +=x;130 }131 else
132 {133 baseControl.Width =MinWidth;134 }135 break;136
137 }138 pPoint =Cursor.Position;139 }
到此为止，功能已经基本上实现。
完成代码如下：
MoveControl
1
10 usingSystem;11 usingSystem.Collections.Generic;12 usingSystem.Linq;13 usingSystem.Text;14 usingSystem.Windows.Forms;15 usingSystem.Drawing;16
17 namespaceDragControl18 {19 public classMoveControl20 {21 #region Constructors
22 publicMoveControl(Control ctrl)23 {24 currentControl =ctrl;25 AddEvents();26 }27 #endregion
28
29 #region Fields
30 private Control currentControl; //传入的控件
31 private Point pPoint; //上个鼠标坐标
32 private Point cPoint; //当前鼠标坐标
33 FrameControl fc;//边框控件
34 #endregion
35
36 #region Properties
37
38 #endregion
39
40 #region Methods
41 ///
42 ///挂载事件43 ///
44 private voidAddEvents()45 {46 currentControl.MouseClick += newMouseEventHandler(MouseClick);47 currentControl.MouseDown += newMouseEventHandler(MouseDown);48 currentControl.MouseMove += newMouseEventHandler(MouseMove);49 currentControl.MouseUp += newMouseEventHandler(MouseUp);50 }51
52 ///
53 ///绘制拖拉时的黑色边框54 ///
55 public static voidDrawDragBound(Control ctrl)56 {57 ctrl.Refresh();58 Graphics g =ctrl.CreateGraphics();59 int width =ctrl.Width;60 int height =ctrl.Height;61 Point[] ps = new Point[5]{new Point(0,0),new Point(width -1,0),62 new Point(width -1,height -1),new Point(0,height-1),new Point(0,0)};63 g.DrawLines(newPen(Color.Black), ps);64 }65
66 #endregion
67
68 #region Events
69 ///
70 ///鼠标单击事件：用来显示边框71 ///
72 ///
73 ///
74 protected void MouseClick(objectsender, MouseEventArgs e)75 {76 this.currentControl.Parent.Refresh();//刷新父容器，清除掉其他控件的边框
77 this.currentControl.BringToFront();78 fc = new FrameControl(this.currentControl);79 this.currentControl.Parent.Controls.Add(fc);80 fc.Visible = true;81 fc.Draw();82 }83
84 ///
85 ///鼠标按下事件：记录当前鼠标相对窗体的坐标86 ///
87 void MouseDown(objectsender, MouseEventArgs e)88 {89 pPoint =Cursor.Position;90 }91
92 ///
93 ///鼠标移动事件：让控件跟着鼠标移动94 ///
95 void MouseMove(objectsender, MouseEventArgs e)96 {97 Cursor.Current = Cursors.SizeAll; //当鼠标处于控件内部时，显示光标样式为SizeAll98 //当鼠标左键按下时才触发
99 if (e.Button ==MouseButtons.Left)100 {101 MoveControl.DrawDragBound(this.currentControl);102 if(fc != null ) fc.Visible = false; //先隐藏
103 cPoint = Cursor.Position;//获得当前鼠标位置
104 int x = cPoint.X -pPoint.X;105 int y = cPoint.Y -pPoint.Y;106 currentControl.Location = new Point(currentControl.Location.X + x, currentControl.Location.Y +y);107 pPoint =cPoint;108 }109 }110
111 ///
112 ///鼠标弹起事件：让自定义的边框出现113 ///
114 void MouseUp(objectsender, MouseEventArgs e)115 {116 this.currentControl.Refresh();117 if (fc != null)118 {119 fc.Visible = true;120 fc.Draw();121 }122 }123 #endregion
124 }125 }
FrameControl
1
10 usingSystem;11 usingSystem.Collections.Generic;12 usingSystem.Text;13 usingSystem.Windows.Forms;14 usingSystem.Drawing;15 usingSystem.Drawing.Drawing2D;16
17 namespaceDragControl18 {19 public classFrameControl : UserControl20 {21 #region Constructors
22 ///
23 ///构造函数24 ///
25 publicFrameControl(Control ctrl)26 {27 baseControl =ctrl;28 AddEvents();29 CreateBounds();30 }31 #endregion
32
33 #region Fields
34 const int Band = 6; //调整大小的响应边框
35 private int MinWidth = 20; //最小宽度
36 private int MinHeight = 20;//最小高度
37 Size square = new Size(Band, Band);//小矩形大小
38 Control baseControl; //基础控件，即被包围的控件
39 Rectangle[] smallRects = new Rectangle[8];//边框中的八个小圆圈
40 Rectangle[] sideRects = new Rectangle[4];//四条边框，用来做响应区域
41 Point[] linePoints = new Point[5];//四条边，用于画虚线
42 Graphics g; //画图板
43 Rectangle ControlRect; //控件包含边框的区域
44 private Point pPoint; //上个鼠标坐标
45 private Point cPoint; //当前鼠标坐标
46 privateMousePosOnCtrl mpoc;47 #endregion
48
49 #region Properties
50 ///
51 ///鼠标在控件中位置52 ///
53 enumMousePosOnCtrl54 {55 NONE = 0,56 TOP = 1,57 RIGHT = 2,58 BOTTOM = 3,59 LEFT = 4,60 TOPLEFT = 5,61 TOPRIGHT = 6,62 BOTTOMLEFT = 7,63 BOTTOMRIGHT = 8,64 }65 #endregion
66
67 #region Methods
68 ///
69 ///加载事件70 ///
71 private voidAddEvents()72 {73 this.Name = "FrameControl" +baseControl.Name;74 this.MouseDown += newMouseEventHandler(FrameControl_MouseDown);75 this.MouseMove += newMouseEventHandler(FrameControl_MouseMove);76 this.MouseUp += newMouseEventHandler(FrameControl_MouseUp);77 }78
79 #region 创建边框
80 ///
81 ///建立控件可视区域82 ///
83 private voidCreateBounds()84 {85 //创建边界
86 int X = baseControl.Bounds.X - square.Width - 1;87 int Y = baseControl.Bounds.Y - square.Height - 1;88 int Height = baseControl.Bounds.Height + (square.Height * 2) + 2;89 int Width = baseControl.Bounds.Width + (square.Width * 2) + 2;90 this.Bounds = newRectangle(X, Y, Width, Height);91 this.BringToFront();92 SetRectangles();93 //设置可视区域
94 this.Region = newRegion(BuildFrame());95 g = this.CreateGraphics();96 }97
98 ///
99 ///设置定义8个小矩形的范围100 ///
101 voidSetRectangles()102 {103 //左上
104 smallRects[0] = new Rectangle(new Point(0, 0), square);105 //右上
106 smallRects[1] = new Rectangle(new Point(this.Width - square.Width - 1, 0), square);107 //左下
108 smallRects[2] = new Rectangle(new Point(0, this.Height - square.Height - 1), square);109 //右下
110 smallRects[3] = new Rectangle(new Point(this.Width - square.Width - 1, this.Height - square.Height - 1), square);111 //上中
112 smallRects[4] = new Rectangle(new Point(this.Width / 2 - 1, 0), square);113 //下中
114 smallRects[5] = new Rectangle(new Point(this.Width / 2 - 1, this.Height - square.Height - 1), square);115 //左中
116 smallRects[6] = new Rectangle(new Point(0, this.Height / 2 - 1), square);117 //右中
118 smallRects[7] = new Rectangle(new Point(square.Width + baseControl.Width + 1, this.Height / 2 - 1), square);119
120 //四条边线121 //左上
122 linePoints[0] = new Point(square.Width / 2, square.Height / 2);123 //右上
124 linePoints[1] = new Point(this.Width - square.Width / 2 - 1, square.Height / 2);125 //右下
126 linePoints[2] = new Point(this.Width - square.Width / 2 - 1, this.Height - square.Height / 2);127 //左下
128 linePoints[3] = new Point(square.Width / 2, this.Height - square.Height / 2 - 1);129 //左上
130 linePoints[4] = new Point(square.Width / 2, square.Height / 2);131
132 //整个包括周围边框的范围
133 ControlRect = new Rectangle(new Point(0, 0), this.Bounds.Size);134 }135
136 ///
137 ///设置边框控件可视区域138 ///
139 ///
140 privateGraphicsPath BuildFrame()141 {142 GraphicsPath path = newGraphicsPath();143 //上边框
144 sideRects[0] = new Rectangle(0, 0, this.Width - square.Width - 1, square.Height + 1);145 //左边框
146 sideRects[1] = new Rectangle(0, square.Height + 1, square.Width + 1, this.Height - square.Height - 1);147 //下边框
148 sideRects[2] = new Rectangle(square.Width + 1, this.Height - square.Height - 1, this.Width - square.Width - 1, square.Height + 1);149 //右边框
150 sideRects[3] = new Rectangle(this.Width - square.Width - 1, 0, square.Width + 1, this.Height - square.Height - 1);151
152 path.AddRectangle(sideRects[0]);153 path.AddRectangle(sideRects[1]);154 path.AddRectangle(sideRects[2]);155 path.AddRectangle(sideRects[3]);156 returnpath;157 }158 #endregion
159
160 ///
161 ///绘图162 ///
163 public voidDraw()164 {165 this.BringToFront();166 //g.FillRectangles(Brushes.LightGray, sideRects);//填充四条边框的内部
167 Pen pen = newPen(Color.Black);168 pen.DashStyle = DashStyle.Dot;//设置为虚线,用虚线画四边，模拟微软效果
169 g.DrawLines(pen, linePoints);//绘制四条边线
170 g.FillRectangles(Brushes.White, smallRects); //填充8个小矩形的内部
171 foreach (Rectangle smallRect insmallRects)172 {173 g.DrawEllipse(Pens.Black, smallRect); //绘制8个小椭圆
174 }175 //g.DrawRectangles(Pens.Black, smallRects);//绘制8个小矩形的黑色边线
176 }177
178 ///
179 ///设置光标状态180 ///
181 public bool SetCursorShape(int x, inty)182 {183 Point point = newPoint(x, y);184 if (!ControlRect.Contains(point))185 {186 Cursor.Current =Cursors.Arrow;187 return false;188 }189 else if (smallRects[0].Contains(point))190 {191 Cursor.Current =Cursors.SizeNWSE;192 mpoc =MousePosOnCtrl.TOPLEFT;193 }194 else if (smallRects[1].Contains(point))195 {196 Cursor.Current =Cursors.SizeNESW;197 mpoc =MousePosOnCtrl.TOPRIGHT;198 }199 else if (smallRects[2].Contains(point))200 {201 Cursor.Current =Cursors.SizeNESW;202 mpoc =MousePosOnCtrl.BOTTOMLEFT;203 }204 else if (smallRects[3].Contains(point))205 {206 Cursor.Current =Cursors.SizeNWSE;207 mpoc =MousePosOnCtrl.BOTTOMRIGHT;208 }209 else if (sideRects[0].Contains(point))210 {211 Cursor.Current =Cursors.SizeNS;212 mpoc =MousePosOnCtrl.TOP;213 }214 else if (sideRects[1].Contains(point))215 {216 Cursor.Current =Cursors.SizeWE;217 mpoc =MousePosOnCtrl.LEFT;218 }219 else if (sideRects[2].Contains(point))220 {221 Cursor.Current =Cursors.SizeNS;222 mpoc =MousePosOnCtrl.BOTTOM;223 }224 else if (sideRects[3].Contains(point))225 {226 Cursor.Current =Cursors.SizeWE;227 mpoc =MousePosOnCtrl.RIGHT;228 }229 else
230 {231 Cursor.Current =Cursors.Arrow;232 }233 return true;234 }235
236 ///
237 ///控件移动238 ///
239 private voidControlMove()240 {241 cPoint =Cursor.Position;242 int x = cPoint.X -pPoint.X;243 int y = cPoint.Y -pPoint.Y;244 switch (this.mpoc)245 {246 caseMousePosOnCtrl.TOP:247 if (baseControl.Height - y >MinHeight)248 {249 baseControl.Top +=y;250 baseControl.Height -=y;251 }252 else
253 {254 baseControl.Top -= MinHeight -baseControl.Height;255 baseControl.Height =MinHeight;256 }257 break;258 caseMousePosOnCtrl.BOTTOM:259 if (baseControl.Height + y >MinHeight)260 {261 baseControl.Height +=y;262 }263 else
264 {265 baseControl.Height =MinHeight;266 }267 break;268 caseMousePosOnCtrl.LEFT:269 if (baseControl.Width - x >MinWidth)270 {271 baseControl.Left +=x;272 baseControl.Width -=x;273 }274 else
275 {276 baseControl.Left -= MinWidth -baseControl.Width;277 baseControl.Width =MinWidth;278 }279
280 break;281 caseMousePosOnCtrl.RIGHT:282 if (baseControl.Width + x >MinWidth)283 {284 baseControl.Width +=x;285 }286 else
287 {288 baseControl.Width =MinWidth;289 }290 break;291 caseMousePosOnCtrl.TOPLEFT:292 if (baseControl.Height - y >MinHeight)293 {294 baseControl.Top +=y;295 baseControl.Height -=y;296 }297 else
298 {299 baseControl.Top -= MinHeight -baseControl.Height;300 baseControl.Height =MinHeight;301 }302 if (baseControl.Width - x >MinWidth)303 {304 baseControl.Left +=x;305 baseControl.Width -=x;306 }307 else
308 {309 baseControl.Left -= MinWidth -baseControl.Width;310 baseControl.Width =MinWidth;311 }312 break;313 caseMousePosOnCtrl.TOPRIGHT:314 if (baseControl.Height - y >MinHeight)315 {316 baseControl.Top +=y;317 baseControl.Height -=y;318 }319 else
320 {321 baseControl.Top -= MinHeight -baseControl.Height;322 baseControl.Height =MinHeight;323 }324 if (baseControl.Width + x >MinWidth)325 {326 baseControl.Width +=x;327 }328 else
329 {330 baseControl.Width =MinWidth;331 }332 break;333 caseMousePosOnCtrl.BOTTOMLEFT:334 if (baseControl.Height + y >MinHeight)335 {336 baseControl.Height +=y;337 }338 else
339 {340 baseControl.Height =MinHeight;341 }342 if (baseControl.Width - x >MinWidth)343 {344 baseControl.Left +=x;345 baseControl.Width -=x;346 }347 else
348 {349 baseControl.Left -= MinWidth -baseControl.Width;350 baseControl.Width =MinWidth;351 }352 break;353 caseMousePosOnCtrl.BOTTOMRIGHT:354 if (baseControl.Height + y >MinHeight)355 {356 baseControl.Height +=y;357 }358 else
359 {360 baseControl.Height =MinHeight;361 }362 if (baseControl.Width + x >MinWidth)363 {364 baseControl.Width +=x;365 }366 else
367 {368 baseControl.Width =MinWidth;369 }370 break;371
372 }373 pPoint =Cursor.Position;374 }375
376 #endregion
377
378 #region Events
379 ///
380 ///鼠标按下事件：记录当前鼠标相对窗体的坐标381 ///
382 void FrameControl_MouseDown(objectsender, MouseEventArgs e)383 {384 pPoint =Cursor.Position;385 }386
387 ///
388 ///鼠标移动事件：让控件跟着鼠标移动389 ///
390 void FrameControl_MouseMove(objectsender, MouseEventArgs e)391 {392 if (e.Button ==MouseButtons.Left)393 {394 this.Visible = false;395 MoveControl.DrawDragBound(baseControl);396 ControlMove();397 }398 else
399 {400 this.Visible = true;401 SetCursorShape(e.X, e.Y); //更新鼠标指针样式
402 }403 }404
405 ///
406 ///鼠标弹起事件：让自定义的边框出现407 ///
408 void FrameControl_MouseUp(objectsender, MouseEventArgs e)409 {410 this.baseControl.Refresh(); //刷掉黑色边框
411 this.Visible = true;412 CreateBounds();413 Draw();414 }415 #endregion
416 }417 }
四、遗留问题
1.ListBox存在拖拉高度时，存在莫名奇妙的BUG。
2.目前该版本只支持单控件的拖拉，多控件同时拖拉等下次有空再弄。
五、附源代码下载
SamWang
2012-05-14
作者：SamWang
出处：http://wangshenhe.cnblogs.com/
本文版权归作者和博客园共有，欢迎围观转载。转载时请您务必在文章明显位置给出原文链接，谢谢您的合作。
