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。
/// <summary>
/// 绘图
/// </summary>
public void Draw()
{
this.BringToFront();
Pen pen = new Pen(Color.Black);
pen.DashStyle = DashStyle.Dot;//设置为虚线,用虚线画四边，模拟微软效果
g.DrawLines(pen, linePoints);//绘制四条边线
g.FillRectangles(Brushes.White, smallRects); //填充8个小矩形的内部
foreach (Rectangle smallRect in smallRects)
{
g.DrawEllipse(Pens.Black, smallRect); //绘制8个小椭圆
}
//g.DrawRectangles(Pens.Black, smallRects); //绘制8个小矩形的黑色边线
}
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。
/// <summary>
/// 鼠标单击事件：用来显示边框
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void MouseClick(object sender, MouseEventArgs e)
{
this.currentControl.Parent.Refresh();//刷新父容器，清除掉其他控件的边框
this.currentControl.BringToFront();
fc = new FrameControl(this.currentControl);
this.currentControl.Parent.Controls.Add(fc);
fc.Visible = true;
fc.Draw();
}
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
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
namespace DragControl
{
public class MoveControl
{
#region Constructors
public MoveControl(Control ctrl)
{
currentControl = ctrl;
AddEvents();
}
#endregion
#region Fields
private Control currentControl; //传入的控件
private Point pPoint; //上个鼠标坐标
private Point cPoint; //当前鼠标坐标
FrameControl fc;//边框控件
#endregion
#region Properties
#endregion
#region Methods
/// <summary>
/// 挂载事件
/// </summary>
private void AddEvents()
{
currentControl.MouseClick += new MouseEventHandler(MouseClick);
currentControl.MouseDown += new MouseEventHandler(MouseDown);
currentControl.MouseMove += new MouseEventHandler(MouseMove);
currentControl.MouseUp += new MouseEventHandler(MouseUp);
}
/// <summary>
/// 绘制拖拉时的黑色边框
/// </summary>
public static void DrawDragBound(Control ctrl)
{
ctrl.Refresh();
Graphics g = ctrl.CreateGraphics();
int width = ctrl.Width;
int height = ctrl.Height;
Point[] ps = new Point[5]{new Point(0,0),new Point(width -1,0),
new Point(width -1,height -1),new Point(0,height-1),new Point(0,0)};
g.DrawLines(new Pen(Color.Black), ps);
}
#endregion
#region Events
/// <summary>
/// 鼠标单击事件：用来显示边框
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void MouseClick(object sender, MouseEventArgs e)
{
this.currentControl.Parent.Refresh();//刷新父容器，清除掉其他控件的边框
this.currentControl.BringToFront();
fc = new FrameControl(this.currentControl);
this.currentControl.Parent.Controls.Add(fc);
fc.Visible = true;
fc.Draw();
}
/// <summary>
/// 鼠标按下事件：记录当前鼠标相对窗体的坐标
/// </summary>
void MouseDown(object sender, MouseEventArgs e)
{
pPoint = Cursor.Position;
}
/// <summary>
/// 鼠标移动事件：让控件跟着鼠标移动
/// </summary>
void MouseMove(object sender, MouseEventArgs e)
{
Cursor.Current = Cursors.SizeAll; //当鼠标处于控件内部时，显示光标样式为SizeAll
//当鼠标左键按下时才触发
if (e.Button == MouseButtons.Left)
{
MoveControl.DrawDragBound(this.currentControl);
if (fc != null) fc.Visible = false; //先隐藏
cPoint = Cursor.Position; //获得当前鼠标位置
int x = cPoint.X - pPoint.X;
int y = cPoint.Y - pPoint.Y;
currentControl.Location = new Point(currentControl.Location.X + x, currentControl.Location.Y + y);
pPoint = cPoint;
}
}
/// <summary>
/// 鼠标弹起事件：让自定义的边框出现
/// </summary>
void MouseUp(object sender, MouseEventArgs e)
{
this.currentControl.Refresh();
if (fc != null)
{
fc.Visible = true;
fc.Draw();
}
}
#endregion
}
}
