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C# CSV文件读写

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

namespace OpenCSV
{
    public class CSVFile
    {
        public class CSVFileHelper
        {           
            /// <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 = 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)
                {
                    //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 = 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;
            }
        }
    }
}

using System;
using System.Text;
using System.IO;

namespace OpenCSV
{
    /// <summary> 
    /// FileEncoding 的摘要说明 
    /// </summary> 
    class Common
    {
        /// <summary> 
        /// 获取文件的编码格式 
        /// </summary> 

        /// <summary> 
        /// 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 
        /// </summary> 
        /// <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)
        {
            FileStream fs = new FileStream(FILE_NAME, FileMode.Open, FileAccess.Read);
            Encoding r = GetType(fs);
            fs.Close();
            return r;
        }

        /// <summary> 
        /// 通过给定的文件流，判断文件的编码类型 
        /// </summary> 
        /// <param name=“fs“>文件流</param> 
        /// <returns>文件的编码类型</returns> 
        public static System.Text.Encoding GetType(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 
            Encoding reVal = Encoding.Default;

            BinaryReader r = new 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 = Encoding.UTF8;
            }
            else if (ss[0] == 0xFE && ss[1] == 0xFF && ss[2] == 0x00)
            {
                reVal = Encoding.BigEndianUnicode;
            }
            else if (ss[0] == 0xFF && ss[1] == 0xFE && ss[2] == 0x41)
            {
                reVal = Encoding.Unicode;
            }
            r.Close();
            return reVal;

        }

        /// <summary> 
        /// 判断是否是不带 BOM 的 UTF8 格式 
        /// </summary> 
        /// <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;
        }
    }
} 

其他的一些方法，搜集：

public static class CsvFileReader
    {
        public static string[][] Read(string fullname)
        {
            if (!File.Exists(fullname)) return new string[][] { };
            var lines = File.ReadAllLines(fullname).Skip(1);
            var list=new List<string[]>();
            var builder = new StringBuilder();
            foreach (var line in lines)
            {
                builder.Clear();
                var comma = false;
                var array = line.ToCharArray();
                var values = new List<string>();
                var length = array.Length - 1;
                var index = 0;
                while (index < length)
                {
                    var item = array[index++];
                    switch (item)
                    {
                        case ',':
                            if (comma)
                            {
                                builder.Append(item);
                            }
                            else
                            {
                                values.Add(builder.ToString());
                                builder.Clear();
                            }
                            break;
                        case '"':
                            comma = !comma;
                            break;
                        default:
                            builder.Append(item);
                            break;
                    }
                }
                var count = values.Count;
                if (count == 0) continue;
                list.Add(values.ToArray());
            }
            return list.ToArray();
        }
    }