CSV的导入导出

using System;
using System.Data;
using System.IO;

namespace COMMON
{
    public class CSVhelperClass
    {
        /// <summary>  
        /// 导出报表为Csv  
        /// </summary>  
        /// <param name="dt">DataTable</param>  
        /// <param name="strFilePath">物理路径</param>          
        /// <param name="columname">字段标题,逗号分隔</param>  
        public string dt2csv(DataTable dt, string strFilePath, string columname)
        {
            try
            {
                string strBufferLine = "";
                StreamWriter strmWriterObj = new StreamWriter(strFilePath, false, System.Text.Encoding.UTF8);                 
                strmWriterObj.WriteLine(columname);
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    strBufferLine = "";
                    for (int j = 0; j < dt.Columns.Count; j++)
                    {
                        if (j > 0)
                            strBufferLine += ",";
                        strBufferLine += dt.Rows[i][j].ToString();
                    }
                    strmWriterObj.WriteLine(strBufferLine);
                }
                strmWriterObj.Close();
                return "备份成功";
            }
            catch (Exception ex)
            {
                return "备份失败 " + ex.ToString();
            }
        }

        /// <summary>  
        /// 将Csv读入DataTable  
        /// </summary>  
        /// <param name="filePath">csv文件路径</param>  
        /// <param name="n">表示第n行是字段title,第n+1行是记录开始</param>  
        public DataTable csv2dt(string filePath, int n, DataTable dt)
        {
            StreamReader reader = new StreamReader(filePath, System.Text.Encoding.UTF8, false);
            int i = 0, m = 0;
            //返回下一个可用的字符
            //返回值表示下一个要读取的字符的整数，或者，如果没有更多的可用字符或该流不支持查找，则为 -1。
            reader.Peek();
            while (reader.Peek() > 0)
            {
                m = m + 1;
                string str = reader.ReadLine();
                if (m >= n + 1)
                {
                    string[] lstSplit = str.Split(',');

                    System.Data.DataRow dr = dt.NewRow();
                    for (i = 0; i < lstSplit.Length; i++)
                    {
                        dr[i] = lstSplit[i];
                    }
                    dt.Rows.Add(dr);
                }
                else
                {
                    string[] lstTitle = str.Split(',');
                    for (i = 0; i < lstTitle.Length; i++)
                    {
                        DataColumn columnItem = new DataColumn(lstTitle[i],typeof(string));
                        dt.Columns.Add(columnItem);
                    }
                }
            }
            reader.Close();
            return dt;
        } 
    }
}