(三)C#关于txt文件的读取和写入

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace textTest
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        private string downLoadFileName = "C:/Users/zuomeiyan/Desktop/DISPUTE.TXT";
        //读取系统临时文件
        private string savePath =System.Environment.GetEnvironmentVariable("TEMP")+"\\new.txt";

        protected void Page_Load(object sender, EventArgs e)
        {
            ReadFromTxt();
        }
        protected void ReadFromTxt()
        {
            //读取文件
            FileStream fs = new FileStream(downLoadFileName, FileMode.Open);
            StreamReader sr = new StreamReader(fs, Encoding.UTF8);
            //try是为了防止代码出现问题是文件流不能关闭
            try
            {
                //新建list存放读取的数据
                List<string> datalist = new List<string>();
                //文件中不到末尾就一直读取
                while (!sr.EndOfStream)
                {
                    //读取每一行
                    string strDataOld = sr.ReadLine();
                    string strData = "";
                    //如果文件的每一行的第一个字符和最后一个字符是|，则去除
                    if (strDataOld[0] == '|')
                    {
                        strData = strDataOld.Substring(1, strDataOld.Length - 1);
                    }
                    if (strDataOld[strDataOld.Length - 1] == '|')
                    {
                        strData = strDataOld.Substring(1, strDataOld.Length - 2);
                    }  
                    //加到list中
                    datalist.Add(strData);
                }
                var lineNo = datalist.Count;
                //去除不用的行，本代码中是出去第一行第三行和最后一行
                List<string> newdatalist = new List<string>();
                for (int i = 1; i < lineNo - 1; i++)
                {
                    if (i != 2)
                    {
                        newdatalist.Add(datalist[i]);
                    }
                }
                WriteToNewTxt(newdatalist);
            }
            catch
            {
            }
            finally
            {
                //关闭文件流
                sr.Close();
                fs.Close();
            }
        }
        protected void WriteToNewTxt(List<string> lst)
        {
            //将生成的新list写入文件
            FileStream fsnew = new FileStream(savePath, FileMode.Create);
            StreamWriter sw = new StreamWriter(fsnew, Encoding.UTF8);
            try
            {
                
                sw.Flush();
                for (int i = 0; i < lst.Count; i++)
                {
                    sw.WriteLine(lst[i]);
                }
            }catch {}
            finally
            {
                //关闭此文件 
                sw.Flush();
                sw.Close();
                fsnew.Close();
            }  
        }
    }
}