using System.Data;

using System.IO;

namespace DotNet.Utilities

{

    /// <summary>

    /// CSV文件转换类

    /// </summary>

    public static class CsvHelper

    {

        /// <summary>

        /// 导出报表为Csv

        /// </summary>

        /// <param name="dt">DataTable</param>

        /// <param name="strFilePath">物理路径</param>

        /// <param name="tableheader">表头</param>

        /// <param name="columname">字段标题,逗号分隔</param>

        public static bool dt2csv(DataTable dt, string strFilePath, string tableheader, string columname)

        {

            try

            {

                string strBufferLine = "";

                StreamWriter strmWriterObj = new StreamWriter(strFilePath, false, System.Text.Encoding.UTF8);

                strmWriterObj.WriteLine(tableheader);

                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 true;

            }

            catch

            {

                return false;

            }

        }

        /// <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 static DataTable csv2dt(string filePath, int n, DataTable dt)

        {

            StreamReader reader = new StreamReader(filePath, System.Text.Encoding.UTF8, false);

            int i = 0, m = 0;

            reader.Peek();

            while (reader.Peek() > 0)

            {

                m = m + 1;

                string str = reader.ReadLine();

                if (m >= n + 1)

                {

                    string[] split = str.Split(',');

                    System.Data.DataRow dr = dt.NewRow();

                    for (i = 0; i < split.Length; i++)

                    {

                        dr[i] = split[i];

                    }

                    dt.Rows.Add(dr);

                }

            }

            return dt;

        }

    }

}

//该代码片段来自于: http://www.sharejs.com/codes/csharp/8609