WinForm中TextBox控件循环自动滚动示例

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace WindowsApplication27
...{
/**//// <summary>
/// 演示如何在TextBox中让文字循环滚动:
/// </summary>
public partial class Form1 : Form
...{
public Form1()
...{
InitializeComponent();

this.textBox1.Clear();
for (int i = 0; i <= 20;i++ )
...{
this.textBox1.Text += string.Format("{0}:jinjazz__{1} ", i,i);
}
this.timer1.Interval = 200;
this.timer1.Start();
}

//发送消息
[DllImport("user32.dll", EntryPoint = "SendMessage")]
public static extern int SendMessage(IntPtr hWnd, int wMsg, int wParam, int lParam);
//获取滚动条位置
[DllImport("user32")]
public static extern int GetScrollPos(IntPtr hwnd, int nBar);
//设置滚动条位置
[DllImport("user32.dll")]
static extern int SetScrollPos(IntPtr hWnd, int nBar,
int nPos, bool bRedraw);

public const int EM_LINESCROLL = 0xb6;

private void timer1_Tick(object sender, EventArgs e)
...{
int i= GetScrollPos(this.textBox1.Handle,1);

//向下滚动一行
SendMessage(this.textBox1.Handle, EM_LINESCROLL, 0, 1);//0，1代表垂直滚动条向下滚动

//判断是否有位置变化，如果没有则说明到了底部，返回开始处
if (i == GetScrollPos(this.textBox1.Handle, 1))
...{
//回到顶部，这里用SetScrollPos似乎有问题，滚动条和文字不是同步更新
this.textBox1.SelectionStart = 0;
this.textBox1.SelectionLength = 1;
this.textBox1.ScrollToCaret();
this.textBox1.SelectionLength = 0;
}
Console.WriteLine(i);
}
private void textBox1_MouseEnter(object sender, EventArgs e)
...{
this.timer1.Stop();
}
private void textBox1_MouseLeave(object sender, EventArgs e)
...{
this.timer1.Start();
}
}
}