/// <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 bool SaveCSV(DataTable dt, string fullPath)
        {
            try
            {
                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 = 0; i < dt.Columns.Count; i++)
                {
                    data += "\"" + dt.Columns[i].ColumnName.ToString() + "\"";
                    if (i < dt.Columns.Count - 1)
                    {
                        data += ",";
                    }
                }
                sw.WriteLine(data);
                //写出各行数据
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    data = "";
                    for (int j = 0; j < dt.Columns.Count; j++)
                    {
                        string str = dt.Rows[i][j].ToString();
                        str = string.Format("\"{0}\"", str);
                        data += str;
                        if (j < dt.Columns.Count - 1)
                        {
                            data += ",";
                        }
                    }
                    sw.WriteLine(data);
                }
                sw.Close();
                fs.Close();
                return true;
            }
            catch
            {
                return false;
            }
        }
        /// <summary>
        /// 读取CSV文件到DataTable中
        /// </summary>
        /// <param name="filePath">CSV的文件路径</param>
        /// <returns></returns>
        public static DataTable ReadCSV(string filePath)
        {
            DataTable dt = new DataTable();
            int lineNumber = 0;
            using (CsvFileReader reader = new CsvFileReader(filePath))
            {
                CsvRow row = new CsvRow();
                while (reader.ReadRow(row))
                {
 
                    if (0 == lineNumber)
                    {
                        foreach (string s in row)
                        {
                            dt.Columns.Add(s.Replace("\"", ""));
                        }
                    }
                    else
                    {
                        int index = 0;
                        DataRow dr = dt.NewRow();
                        foreach (string s in row)
                        {
                            dr[index] = s.Replace("\"", "");
                            index++;
                        }
                        dt.Rows.Add(dr);
                    }
                    lineNumber++;
                }
            }
            return dt;
        }

   public class CsvRow : List<string>
    {
        public string LineText { get; set; }
    }
    public class CsvFileReader : StreamReader
    {
        public CsvFileReader(Stream stream)
            : base(stream)
        {
        }
 
        public CsvFileReader(string filename)
            : base(filename)
        {
        }
 
        /// <summary>  
        /// Reads a row of data from a CSV file  
        /// </summary>  
        /// <param name="row"></param>  
        /// <returns></returns>  
        public bool ReadRow(CsvRow row)
        {
            row.LineText = ReadLine();
            if (String.IsNullOrEmpty(row.LineText))
                return false;
 
            int pos = 0;
            int rows = 0;
 
            while (pos < row.LineText.Length)
            {
                string value;
 
                // Special handling for quoted field  
                if (row.LineText[pos] == '"')
                {
                    // Skip initial quote  
                    pos++;
 
                    // Parse quoted value  
                    int start = pos;
                    while (pos < row.LineText.Length)
                    {
                        // Test for quote character  
                        if (row.LineText[pos] == '"')
                        {
                            // Found one  
                            pos++;
 
                            // If two quotes together, keep one  
                            // Otherwise, indicates end of value  
                            if (pos >= row.LineText.Length || row.LineText[pos] != '"')
                            {
                                pos--;
                                break;
                            }
                        }
                        pos++;
                    }
                    value = row.LineText.Substring(start, pos - start);
                    value = value.Replace("\"\"", "\"");
                }
                else
                {
                    // Parse unquoted value  
                    int start = pos;
                    while (pos < row.LineText.Length && row.LineText[pos] != ',')
                        pos++;
                    value = row.LineText.Substring(start, pos - start);
                }
 
                // Add field to list  
                if (rows < row.Count)
                    row[rows] = value;
                else
                    row.Add(value);
                rows++;
 
                // Eat up to and including next comma  
                while (pos < row.LineText.Length && row.LineText[pos] != ',')
                    pos++;
                if (pos < row.LineText.Length)
                    pos++;
            }
            // Delete any unused items  
            while (row.Count > rows)
                row.RemoveAt(rows);
 
            // Return true if any columns read  
            return (row.Count > 0);
        }
    }