public class XlsHelper

    {

        public static System.Data.DataSet GetXlsToDataSet(string filePath)

        {

            using (var stream = File.Open(filePath, FileMode.Open, FileAccess.Read))

            {

                // Auto-detect format, supports:

                //  - Binary Excel files (2.0-2003 format; *.xls)

                //  - OpenXml Excel files (2007 format; *.xlsx)

                using (var reader = ExcelReaderFactory.CreateReader(stream))

                {

                    // Choose one of either 1 or 2:

                    // 1. Use the reader methods

                    do

                    {

                        while (reader.Read())

                        {

                            // reader.GetDouble(0);

                        }

                    } while (reader.NextResult());

                    // 2. Use the AsDataSet extension method

                    var result = reader.AsDataSet();

                    return result;

                    // The result of each spreadsheet is in result.Tables

                }

            }

        }

    }

System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);