public class ExcelFileHelper

    {

        public static bool SaveAsCsv(string excelFilePath, string destinationCsvFilePath)

        {

            using (var stream = new FileStream(excelFilePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))

            {

                IExcelDataReader reader = null;

                if (excelFilePath.EndsWith(".xls"))

                {

                    reader = ExcelReaderFactory.CreateBinaryReader(stream);

                }

                else if (excelFilePath.EndsWith(".xlsx"))

                {

                    reader = ExcelReaderFactory.CreateOpenXmlReader(stream);

                }

                if (reader == null)

                    return false;

                var ds = reader.AsDataSet(new ExcelDataSetConfiguration()

                {

                    ConfigureDataTable = (tableReader) => new ExcelDataTableConfiguration()

                    {

                        UseHeaderRow = false

                    }

                });

                var csvContent = string.Empty;

                int row_no = ;

                while (row_no < ds.Tables[].Rows.Count)

                {

                    var arr = new List<string>();

                    for (int i = ; i < ds.Tables[].Columns.Count; i++)

                    {

                        arr.Add(ds.Tables[].Rows[row_no][i].ToString());//需要做处理

                    }

                    row_no++;

                    csvContent += string.Join(",", arr.ToArray()) + "\n";

                }

                StreamWriter csv = new StreamWriter(destinationCsvFilePath, false,Encoding.UTF8);

                csv.Write(csvContent);

                csv.Close();

                return true;

            }

        }

    }