label左右来回运动

程序代码：

if ("label1.Left > form1.Right")
            {
                label5.Left++;
            }
            else
                label5.Left--;   

程序代码：

/*

 * 文件名: ControlMove.cs

 * 编写：ZhouFeng

 * 日期：2010/12/21

 *

 * 编程中国(bbs.bccn.net)

 */

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using System.Drawing;

namespace LabelMove
{
    /*控件移动实体*/
    public class ControlMove
    {
        /// <summary>
        /// 移动方向
        /// </summary>
        public enum MoveDirection
        {
            Left,                                                           // 向左移动
            Right,                                                          // 向右移动
            Up,                                                             // 向上移动
            Down                                                            // 向下移动
        }

        /// <summary>
        /// 移动操作委托
        /// </summary>
        /// <param name="offset">偏移像素</param>
        /// <param name="direction">方向</param>
        internal delegate void ControlMoveDlgt(int offset, MoveDirection direction);

        /// <summary>
        /// 获取控件位置操作委托
        /// </summary>
        /// <returns>控件委托</returns>
        internal delegate Point GetControlLocationDlgt();

        #region 成员变量

        private Control cntrl;                                              // 要移动的控件
        private Thread moveThread;                                          // 移动控件的线程
        private static bool hasCreateInstance;                              // 是否具有该对象实例
        private const string ThreadName = "ThreadMoveControl";              // 线程名称
        private Point startLocation;                                        // 开始移动位置
        private Point endLocation;                                          // 结束移动位置
        private int offset;                                                 // 移动像素
        private MoveDirection direction;                                    // 初始移动方向

        #endregion

        #region 属性

        public Point StartLocation
        {
            get
            {
                return this.startLocation;
            }
            set
            {
                this.startLocation = value;
            }
        }

        public Point EndLocation
        {
            get
            {
                return this.endLocation;
            }
            set
            {
                this.endLocation = value;
            }
        }

        public int Offset
        {
            get
            {
                return offset;
            }
            set
            {
                this.offset = value;
            }
        }

        public MoveDirection ControlMoveDirection
        {
            get
            {
                return direction;
            }
            set
            {
                direction = value;
            }
        }

        #endregion

        #region 构造函数相关

        static ControlMove()
        {
            hasCreateInstance = false;             
        }

        private ControlMove(Control pCntrl)
            : this( pCntrl, MoveDirection.Right, Point.Empty, Point.Empty, 1)
        {
        }

        private ControlMove(Control pCntrl,
            MoveDirection direction,
            Point pStartPoint,
            Point pEndPoint,
            int pOffset)
        {
            Init();
            this.cntrl = pCntrl;
            startLocation = pStartPoint;
            endLocation = pEndPoint;
            this.direction = direction;
            this.offset = pOffset;
        }

        ~ControlMove()
        {
            try
            {
                if (moveThread.ThreadState == ThreadState.Running)
                {
                    moveThread.Abort();
                }

            }
            catch (ThreadAbortException ex)
            {
                // Eat this exception
            }
        }

        #endregion

        #region 封装方法

        /// <summary>
        /// 对象初始化
        /// </summary>
        private void Init()
        {
            /*
             * 线程实例初始化
             */
            moveThread = new Thread( new ThreadStart( ThreadEntry));
            moveThread.IsBackground = true;
        }

        /// <summary>
        /// 线程入口
        /// </summary>
        private void ThreadEntry()
        {
            /// 最大移动像素
            int maxMovePixel = this.cntrl.Parent.Right - this.cntrl.Right;
            /// 移动委托实例
            ControlMoveDlgt moveDlgt = new ControlMoveDlgt( ChangeControlLocation);
            /// 获取控件位置委托实例
            GetControlLocationDlgt getLocationDlgt = new GetControlLocationDlgt( GetControlLocation);
            /// 临时变量
            Point tempPoint = Point.Empty;

            lock (this)
            {
                while (true)
                {
                    tempPoint = (Point)this.cntrl.Invoke(getLocationDlgt);

                    /// 设置当前移动方向
                    SetCurrentMoveDirection( tempPoint);
                    this.cntrl.Invoke(moveDlgt, offset, this.direction);
                }
            }
        }

        /// <summary>
        /// 获取控件位置
        /// </summary>
        /// <returns>位置</returns>
        private Point GetControlLocation()
        {
            if (this.cntrl != null)
            {
                return this.cntrl.Location;
            }
            else
            {
                return Point.Empty;
            }
        }

        /// <summary>
        /// 移动控件
        /// </summary>
        /// <param name="offset">移动大小</param>
        /// <param name="direction">移动方向</param>
        private void ChangeControlLocation( int offset, MoveDirection direction)
        {
            if (this.cntrl != null)
            {
                switch (direction)
                {
                    case MoveDirection.Left:        /*向左移动*/
                        this.cntrl.Location = new Point(this.cntrl.Left - offset, this.cntrl.Top);
                        break;
                    case MoveDirection.Right:       /*向右移动*/
                        this.cntrl.Location = new Point(this.cntrl.Left + offset, this.cntrl.Top);
                        break;
                    case MoveDirection.Up:          /*向上移动*/
                        this.cntrl.Location = new Point(this.cntrl.Left, this.cntrl.Top - offset);
                        break;
                    case MoveDirection.Down:        /*向下移动*/
                        this.cntrl.Location = new Point(this.cntrl.Left, this.cntrl.Top + offset);
                        break;
                }
            }

            // Prompt error.
        }

        /// <summary>
        /// 设置当前移动方向
        /// </summary>
        private void SetCurrentMoveDirection( Point currentPoint)
        {
            switch (direction)
            {
                case MoveDirection.Right:
                    if (currentPoint.X >= this.endLocation.X)
                    {
                        this.direction = MoveDirection.Left;
                        Thread.Sleep(100);
                    }
                    break;
                case MoveDirection.Left:
                    if (currentPoint.X <= this.startLocation.X)
                    {
                        this.direction = MoveDirection.Right;
                        Thread.Sleep(100);
                    }
                    break;
                case MoveDirection.Up:
                    if (currentPoint.Y <= this.startLocation.Y)
                    {
                        this.direction = MoveDirection.Down;
                        Thread.Sleep(100);
                    }
                    break;
                case MoveDirection.Down:
                    if (currentPoint.Y >= this.endLocation.Y)
                    {
                        this.direction = MoveDirection.Up;
                        Thread.Sleep(100);
                    }
                    break;
            }

        }

        #endregion

        #region 用户操作接口

        /// <summary>
        /// 创建ControlMove实例
        /// </summary>
        /// <param name="pCntrl">从System.Windows.Forms.Control继承的类</param>
        /// <returns>ControlMove对象实例</returns>
        public static ControlMove CreateControlMove( Control pCntrl)
        {
            if (hasCreateInstance)
            {
                throw new Exception("该对象实例已经被创建!");
            }
            else
            {
                hasCreateInstance = true;

                return new ControlMove( pCntrl);
            }
        }

        /// <summary>
        /// 设置移动的控件
        /// </summary>
        /// <param name="pCntrl">从System.Windows.Forms.Control继承的类</param>
        public void SetControl(Control pCntrl)
        {
            this.cntrl = pCntrl;
        }

        /// <summary>
        /// 开始移动
        /// </summary>
        public void StartMove()
        {
            if (this.moveThread != null)
            {
                this.moveThread.Start();
            }
        }

        #endregion

    }
}