CSV 文件读写

转自：http://www.cnblogs.com/Clin/archive/2013/03/14/2959022.html

 public class CSVFileHelper
 {
     /// <summary>
     /// 将DataTable中数据写入到CSV文件中
     /// </summary>
     /// <param name="dt">提供保存数据的DataTable</param>
     /// <param name="fileName">CSV的文件路径</param>
     public static void SaveCSV(DataTable dt, string fullPath)
     {
         FileInfo fi = new FileInfo(fullPath);
         if (!fi.Directory.Exists)
         {
             fi.Directory.Create();
         }
         FileStream fs = new FileStream(fullPath, System.IO.FileMode.Create, System.IO.FileAccess.Write);
         //StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.Default);
         StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.UTF8);
         string data = "";
         //写出列名称
         for (int i = ; i < dt.Columns.Count; i++)
         {
             data += dt.Columns[i].ColumnName.ToString();
             if (i < dt.Columns.Count - )
             {
                 data += ",";
             }
         }
         sw.WriteLine(data);
         //写出各行数据
         for (int i = ; i < dt.Rows.Count; i++)
         {
             data = "";
             for (int j = ; 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 - )
                 {
                     data += ",";
                 }
             }
             sw.WriteLine(data);
         }
         sw.Close();
         fs.Close();
         DialogResult result = MessageBox.Show("CSV文件保存成功！");
         if (result == DialogResult.OK)
         {
             System.Diagnostics.Process.Start("explorer.exe", Common.PATH_LANG);
         }
     }

     /// <summary>
     /// 将CSV文件的数据读取到DataTable中
     /// </summary>
     /// <param name="fileName">CSV文件路径</param>
     /// <returns>返回读取了CSV数据的DataTable</returns>
     public static DataTable OpenCSV(string filePath)
     {
         Encoding encoding = Common.GetType(filePath); //Encoding.ASCII;//
         DataTable dt = new DataTable();
         FileStream fs = new FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read);

         //StreamReader sr = new StreamReader(fs, Encoding.UTF8);
         StreamReader sr = new StreamReader(fs, encoding);
         //string fileContent = sr.ReadToEnd();
         //encoding = sr.CurrentEncoding;
         //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 = ;
         //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)
         {
             //strLine = Common.ConvertStringUTF8(strLine, encoding);
             //strLine = Common.ConvertStringUTF8(strLine);

             if (IsFirst == true)
             {
                 tableHead = strLine.Split(',');
                 IsFirst = false;
                 columnCount = tableHead.Length;
                 //创建列
                 for (int i = ; i < columnCount; i++)
                 {
                     DataColumn dc = new DataColumn(tableHead[i]);
                     dt.Columns.Add(dc);
                 }
             }
             else
             {
                 aryLine = strLine.Split(',');
                 DataRow dr = dt.NewRow();
                 for (int j = ; j < columnCount; j++)
                 {
                     dr[j] = aryLine[j];
                 }
                 dt.Rows.Add(dr);
             }
         }
         if (aryLine != null && aryLine.Length > )
         {
             dt.DefaultView.Sort = tableHead[] + " " + "asc";
         }

         sr.Close();
         fs.Close();
         return dt;
     }
 }