c#中WinForm的TextBox循环自动滚动示例

这个问题来自论坛提问，演示代码如下


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:


/// 作者jinjazz


/// 作者blog:http://blog.csdn.net/jinjazz


/// </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();


}


}


}