C#简单的文件阅读器

写一个简单的文件阅读器 

1、可以读取大文件（2G）
2、实现首页、下一页、前一页、末页的跳转
3、实现到指定页面的跳转，比如跳转到第**页
4、限制每页显示字符数 1029-4069byte，且用户可自定义该值
5、界面要能实时响应
6、用户可以创建自己的txt文件
7、界面可尽可能的简单

第一步：画界面

第二步：相应事件

上代码

 using System;
 using System.IO;
 using System.Text;
 using System.Windows.Forms;

 namespace txtReader
 {
     public partial class Form1 : Form
     {
         private static int PageTotal = ;
         private static int PageCurrent = ;
         public Form1()
         {
             InitializeComponent();
         }

         /// <summary>
         /// 打开文件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void TsMenuOpen_Click(object sender, EventArgs e)
         {
             if (ofd.ShowDialog() == DialogResult.OK)
             {
                 PageCurrent = ;
                 ReadTxt();
             }
         }

         private void ReadTxt()
         {
             byte[] byts = new byte[decimal.ToInt32(numericUpDown2.Value)];
             using (var fs = File.OpenRead(ofd.FileName))
             {
                 int MValue = decimal.ToInt32(numericUpDown2.Value);
                 int ValueFrom = MValue * PageCurrent;
                 fs.Position = ValueFrom;
                 fs.Read(byts, , MValue);
                 if (byts != null)
                 {
                     int v = (int)((fs.Length / decimal.ToInt32(numericUpDown2.Value)) + );
                     PageTotal = v;
                     txtShow.Text = Encoding.Default.GetString(byts);
                 }
                 fs.Close();
             }
         }

         /// <summary>
         /// 保存文件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void TxMenuSave_Click(object sender, EventArgs e)
         {
             SaveFileDialog sfd = new SaveFileDialog();
             sfd.Filter = "文本文件|*.txt";
             if (DialogResult.OK == sfd.ShowDialog())
             {
                 using (StreamWriter sw = new StreamWriter(sfd.FileName, false, Encoding.Default))
                 {
                     sw.WriteLine(txtShow.Text.Trim());
                     sw.Close();
                 }
             }
         }
         /// <summary>
         /// 关闭文件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void TxMenuClose_Click(object sender, EventArgs e)
         {
             this.Close();
         }
         /// <summary>
         /// 首页
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void BtnFirst_Click(object sender, EventArgs e)
         {
             PageCurrent = ;
             ReadTxt();
         }
         /// <summary>
         /// 上一页
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void BtnPagePre_Click(object sender, EventArgs e)
         {
             PageCurrent = PageCurrent >  ? PageCurrent -  : ;
             ReadTxt();
         }
         /// <summary>
         /// 下一页
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void BtnPageNext_Click(object sender, EventArgs e)
         {
             PageCurrent++;
             ReadTxt();
         }
         /// <summary>
         /// 尾页
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void BtnPageEnd_Click(object sender, EventArgs e)
         {
             PageCurrent = PageTotal - ;
             ReadTxt();
         }
         /// <summary>
         /// 跳转
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void BtnPageTo_Click(object sender, EventArgs e)
         {
             PageCurrent = decimal.ToInt32(numericUpDown1.Value);
             ReadTxt();
         }
     }
 }

总结

这个小功能难点只用这个

确定读取文件的位置，和每次只读指定部分字符

 using (var fs = File.OpenRead(ofd.FileName))
 {
     int MValue = decimal.ToInt32(numericUpDown2.Value);
     int ValueFrom = MValue * PageCurrent;
     fs.Position = ValueFrom;
     fs.Read(byts, , MValue);
     if (byts != null)
     {
         int v = (int)((fs.Length / decimal.ToInt32(numericUpDown2.Value)) + );
         PageTotal = v;
         txtShow.Text = Encoding.Default.GetString(byts);
     }
     fs.Close();
 }

最后附上项目下载源码txtReader.zip