读写CSV文件

             var allFiles = Directory.GetFiles(@"D:\uploadpdf", "*.csv");
             string dataIsNull = @"D:\dataisnull.txt";
             string matchLog = @"D:\matchLog.txt";
             foreach (var filePath in allFiles)
             {
                 DataTable dt = new DataTable();
                 FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
                 StreamReader streamReader = new StreamReader(fileStream);
                 //记录每次读取的一行记录
                 string strLine = string.Empty;
                 //记录每行记录中的各字段的内容
                 string[] aryLine = null;
                 string[] tableHead = null;
                 //标示列数
                 int columCount = ;
                 //标示是否是读取的第一行
                 bool isFirst = true;
                 Console.Out.WriteLine("");
                 StringBuilder headBuilder = new StringBuilder();
                 //逐行读取CSV中的数据
                 while ((strLine = streamReader.ReadLine()) != null)
                 {
                     if (isFirst)
                     {
                         tableHead = strLine.Split(',');
                         isFirst = false;
                         columCount = tableHead.Length;
                         //创建列
                         foreach (var head in tableHead)
                         {
                             DataColumn column = new DataColumn(head);
                             dt.Columns.Add(column);
                             headBuilder.AppendFormat("{0}\t\t\t", head);
                         }
                         if (headBuilder.Length != )
                         {
                             using (StreamWriter sw = File.AppendText(matchLog))
                             {
                                 sw.WriteLine(headBuilder.ToString());
                             }
                         }
                     }
                     else
                     {
                         aryLine = strLine.Split(',');
                         DataRow row = dt.NewRow();
                         if (aryLine.Length == columCount)
                         {
                             for (int i = ; i < columCount; i++)
                             {
                                 row[i] = aryLine[i];
                             }
                         }
                         dt.Rows.Add(row);
                     }
                 }
                 if (aryLine != null && aryLine.Length > )
                 {
                     dt.DefaultView.Sort = tableHead[] + " asc";
                 }
                 streamReader.Close();
                 fileStream.Close();
                 if (dt.Rows.Count == )
                 {
                     //OutputLog(dataIsNull, string.Format("{0} data is null.", filePath));
                     continue;
                 }
                 StringBuilder mpAttributesLog = new StringBuilder();
 
                 foreach (DataRow row in dt.Rows)
                 {
                     //var values = row.ItemArray;
                     //foreach (var head in tableHead)
                     //{
                     //    mpAttributesLog.AppendFormat("{0}\t\t\t", row[head]);
                     //}
                     mpAttributesLog.Append(string.Join("\t\t\t", row.ItemArray));
                     if (mpAttributesLog.Length != )
                     {
                         using (StreamWriter sw = File.AppendText(matchLog))
                         {
                             sw.WriteLine(mpAttributesLog.ToString());
                             mpAttributesLog.Clear();
                         }
                     }
                 }
             }