c# 对CSV文件操作(写入、读取、修改)

    一、DataTable数据写入CSV文件

    
    public static void SaveCSV(DataTable dt, string fullPath)//table数据写入csv
    {
      System.IO.FileInfo fi = new System.IO.FileInfo(fullPath);
      if (!fi.Directory.Exists)
      {
        fi.Directory.Create();
      }
      System.IO.FileStream fs = new System.IO.FileStream(fullPath, System.IO.FileMode.Create, 
        System.IO.FileAccess.Write);
      System.IO.StreamWriter sw = new System.IO.StreamWriter(fs, System.Text.Encoding.UTF8);
      string data = "";
     
      for (int i = 0; i < dt.Columns.Count; i++)//写入列名
      {
        data += dt.Columns[i].ColumnName.ToString();
        if (i < dt.Columns.Count - 1)
        {
          data += ",";
        }
      }
      sw.WriteLine(data);
     
      for (int i = 0; i < dt.Rows.Count; i++) //写入各行数据
      {
        data = "";
        for (int j = 0; j < dt.Columns.Count; j++)
        {
          string str = dt.Rows[i][j].ToString();
          str = str.Replace("\"", "\"\"");//替换英文冒号 英文冒号需要换成两个冒号
          if (str.Contains(',') || str.Contains('"')
            || str.Contains('\r') || str.Contains('\n')) //含逗号 冒号 换行符的需要放到引号中
          {
            str = string.Format("\"{0}\"", str);
          }
     
          data += str;
          if (j < dt.Columns.Count - 1)
          {
            data += ",";
          }
        }
        sw.WriteLine(data);
      }
      sw.Close();
      fs.Close();
    }

    二、读取CSV文件到DataTable

    
    public static DataTable OpenCSV(string filePath)//从csv读取数据返回table
    {
      System.Text.Encoding encoding = GetType(filePath); //Encoding.ASCII;//
      DataTable dt = new DataTable();
      System.IO.FileStream fs = new System.IO.FileStream(filePath, System.IO.FileMode.Open, 
        System.IO.FileAccess.Read);
     
      System.IO.StreamReader sr = new System.IO.StreamReader(fs, encoding);
     
      //记录每次读取的一行记录
      string strLine = "";
      //记录每行记录中的各字段内容
      string[] aryLine = null;
      string[] tableHead = null;
      //标示列数
      int columnCount = 0;
      //标示是否是读取的第一行
      bool IsFirst = true;
      //逐行读取CSV中的数据
      while ((strLine = sr.ReadLine()) != null)
      {
        if (IsFirst == true)
        {
          tableHead = strLine.Split(',');
          IsFirst = false;
          columnCount = tableHead.Length;
          //创建列
          for (int i = 0; i < columnCount; i++)
          {
            DataColumn dc = new DataColumn(tableHead[i]);
            dt.Columns.Add(dc);
          }
        }
        else
        {
          aryLine = strLine.Split(',');
          DataRow dr = dt.NewRow();
          for (int j = 0; j < columnCount; j++)
          {
            dr[j] = aryLine[j];
          }
          dt.Rows.Add(dr);
        }
      }
      if (aryLine != null && aryLine.Length > 0)
      {
        dt.DefaultView.Sort = tableHead[0] + " " + "asc";
      }
     
      sr.Close();
      fs.Close();
      return dt;
    }
    /// 给定文件的路径,读取文件的二进制数据,判断文件的编码类型
    /// <param name="FILE_NAME">文件路径</param>
    /// <returns>文件的编码类型</returns>
     
    public static System.Text.Encoding GetType(string FILE_NAME)
    {
      System.IO.FileStream fs = new System.IO.FileStream(FILE_NAME, System.IO.FileMode.Open, 
        System.IO.FileAccess.Read);
      System.Text.Encoding r = GetType(fs);
      fs.Close();
      return r;
    }
     
    /// 通过给定的文件流,判断文件的编码类型
    /// <param name="fs">文件流</param>
    /// <returns>文件的编码类型</returns>
    public static System.Text.Encoding GetType(System.IO.FileStream fs)
    {
      byte[] Unicode = new byte[] { 0xFF, 0xFE, 0x41 };
      byte[] UnicodeBIG = new byte[] { 0xFE, 0xFF, 0x00 };
      byte[] UTF8 = new byte[] { 0xEF, 0xBB, 0xBF }; //带BOM
      System.Text.Encoding reVal = System.Text.Encoding.Default;
     
      System.IO.BinaryReader r = new System.IO.BinaryReader(fs, System.Text.Encoding.Default);
      int i;
      int.TryParse(fs.Length.ToString(), out i);
      byte[] ss = r.ReadBytes(i);
      if (IsUTF8Bytes(ss) || (ss[0] == 0xEF && ss[1] == 0xBB && ss[2] == 0xBF))
      {
        reVal = System.Text.Encoding.UTF8;
      }
      else if (ss[0] == 0xFE && ss[1] == 0xFF && ss[2] == 0x00)
      {
        reVal = System.Text.Encoding.BigEndianUnicode;
      }
      else if (ss[0] == 0xFF && ss[1] == 0xFE && ss[2] == 0x41)
      {
        reVal = System.Text.Encoding.Unicode;
      }
      r.Close();
      return reVal;
    }
     
    /// 判断是否是不带 BOM 的 UTF8 格式
    /// <param name="data"></param>
    /// <returns></returns>
    private static bool IsUTF8Bytes(byte[] data)
    {
      int charByteCounter = 1;  //计算当前正分析的字符应还有的字节数
      byte curByte; //当前分析的字节.
      for (int i = 0; i < data.Length; i++)
      {
        curByte = data[i];
        if (charByteCounter == 1)
        {
          if (curByte >= 0x80)
          {
            //判断当前
            while (((curByte <<= 1) & 0x80) != 0)
            {
              charByteCounter++;
            }
            //标记位首位若为非0 则至少以2个1开始 如:110XXXXX...........1111110X 
            if (charByteCounter == 1 || charByteCounter > 6)
            {
              return false;
            }
          }
        }
        else
        {
          //若是UTF-8 此时第一位必须为1
          if ((curByte & 0xC0) != 0x80)
          {
            return false;
          }
          charByteCounter--;
        }
      }
      if (charByteCounter > 1)
      {
        throw new Exception("非预期的byte格式");
      }
      return true;
    }

    三、修改文件名称

    我们需要保存历史数据 或者实时的知道那个文件被修改 可以通过改变文件的名称 如加上当天的日期等等。

    
    public static bool ChangeFileName(string OldPath, string NewPath) 
    {
      bool re = false;
      try 
      {
        if (File.Exists(OldPath)) 
        {
          File.Move(OldPath, NewPath);
          re = true;
        }
      }
      catch 
      {
        re = false;
      }
      return re;
    }

    四、CSV文件的数据写入

    直接在网页表单提交数据保存在csv文件中 直接写入文件

    
    public static bool SaveCSV(string fullPath,string Data)
    {
      bool re = true;
      try
      {
        FileStream FileStream = new FileStream(fullPath, FileMode.Append);
        StreamWriter sw = new StreamWriter(FileStream, System.Text.Encoding.UTF8);
        sw.WriteLine(Data);
        //清空缓冲区
        sw.Flush();
        //关闭流
        sw.Close();
        FileStream.Close();
      }
      catch 
      {
        re = false;
      }
      return re;
    }

    以上就是c# 对CSV文件操作(写入、读取、修改)的详细内容,更多关于C# csv文件的资料请关注lingkb其它相关文章!