[C# Control] 走马灯(Marquee)

本来打算自己用Graphics.DrawString的,但是发现效果没有直接利用Label的好
代码没什么可研究的,不过效果似乎还不错

/**////////////////////////////////////////////////////////////////////////////////
//  Marquee.cs
//  走马灯
//
//  @remarks For study purpose
//
//  @author Icebird @date 2006-06-22
/**////////////////////////////////////////////////////////////////////////////////
using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace ControlsEx
{
    /**//// <summary>
    /// 走马灯
    /// </summary>
    public class Marquee : System.Windows.Forms.Control
    {
        /**//// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.Container components = null;

        /**//// <summary>
        /// Constructor
        /// </summary>
        public Marquee()
        {
            InitializeComponent();
        }

        /**//// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if( components != null )
                {
                    components.Dispose();
                    timer.Stop();
                    timer.Dispose();
                    lbl.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        private Timer timer;
        private Label lbl;

        组件设计器生成的代码#region 组件设计器生成的代码
        /**//// <summary>
        /// 设计器支持所需的方法 - 不要使用代码编辑器 
        /// 修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            components = new System.ComponentModel.Container();
            lbl = new Label();
            lbl.Parent = this;
            lbl.AutoSize = true;
            lbl.Visible = false;

            timer = new Timer(components);
            timer.Tick +=new EventHandler(timer_Tick);
            Speed = 1;
            timer.Start();
        }
        #endregion

        /**//// <summary>
        /// 字体
        /// </summary>
        public override Font Font
        {
            get
            {
                return base.Font;
            }
            set
            {
                base.Font = value;
                lbl.Font = value;
            }
        }

        /**//// <summary>
        /// 显示文字，用'|'分隔信息
        /// </summary>
        public override string Text
        {
            get
            {
                return base.Text;
            }
            set
            {
                base.Text = value;
                infos = value.Split(new char[] {'|'});
                if (infos.Length > 0)
                {
                    index = 0;
                    lbl.Text = infos[0];
                }
                else
                    lbl.Text = value;
                offset = -2;
                lbl.Top = (ClientSize.Height - lbl.Height) / 2;
            }
        }

        protected override void OnResize(EventArgs e)
        {
            base.OnResize (e);
            lbl.Top = (ClientSize.Height - lbl.Height) / 2;
        }

        protected override void OnEnabledChanged(EventArgs e)
        {
            base.OnEnabledChanged (e);

            lbl.Visible = Enabled;
            if (Enabled)
                timer.Start();
            else
                timer.Stop();
        }

        private int offset;
        private int index;

        private void timer_Tick(object sender, EventArgs e)
        {
            if (!Enabled)
                return;
            offset++;
            int newLeft = Width - offset;
            lbl.Left = newLeft;
            if (lbl.Text.Length > 0)
                lbl.Visible = true;
            lbl.Invalidate();

            if (newLeft + lbl.Width < 0)
            {
                //显示下一条
                offset = -2;
                index++;
                if (index >= infos.Length)
                    index = 0;
                if (Width > 4)
                    lbl.Left = Width;
                lbl.Text = infos[index];
            }
        }

        private string[] infos;

        /**//// <summary>
        /// 滚动速度，范围1~10，1最快，10最慢
        /// </summary>
        public int Speed
        {
            get
            {
                return timer.Interval / 20;
            }
            set
            {
                if (value < 1 || value > 10)
                    return;
                timer.Stop();
                timer.Interval = value * 20;
                timer.Start();
            }
        }
    }
}