using System;using System.Collections.Generic;using System.IO;using System.Text;namespace CSVDemo{  /// <summary>  /// CSVUtil is a helper class handling csv files.  /// </summary>  public class CSVUtil  {    private CSVUtil()    {    }    //write a new file, existed file will be overwritten    public static void WriteCSV(string filePathName,List<String[]>ls)    {      WriteCSV(filePathName,false,ls);    }    //write a file, existed file will be overwritten if append = false    public static void WriteCSV(string filePathName,bool append, List<String[]> ls)    {      StreamWriter fileWriter=new StreamWriter(filePathName,append,Encoding.Default);      foreach(String[] strArr in ls)      {        fileWriter.WriteLine(String.Join (“,",strArr) );      }      fileWriter.Flush();      fileWriter.Close();          }    public static List<String[]> ReadCSV(string filePathName)    {      List<String[]> ls = new List<String[]>();      StreamReader fileReader=new  StreamReader(filePathName);       string strLine="";      while (strLine != null)      {        strLine = fileReader.ReadLine();        if (strLine != null && strLine.Length>0)        {          ls.Add(strLine.Split(','));          //Debug.WriteLine(strLine);        }      }       fileReader.Close();      return ls;    }      }}