private string GetConStr(string ExcelPath)

        {

            string path = ExcelPath;

            if (!File.Exists(path))

                return null;
string str2 = Path.GetExtension(path).ToLower();

            if ((str2 != ".xls") && (str2 != ".xlsx"))

                 return null;
            string str3 = "Provider = Microsoft.Jet.OLEDB.4.0; Data Source =" + path + "; Extended Properties=Excel 8.0";

            if (str2 == ".xlsx")

                str3 = "Provider = Microsoft.ACE.OLEDB.12.0; Data Source=" + path + "; Extended Properties=Excel 12.0";

            return str3;

        }

        public DataTable ExcelToDataTable(string ExcelPath)

        {

            return ExcelToDataTable(ExcelPath, null);

        }

        public DataTable ExcelToDataTable(string ExcelPath, string SheetName)

        {

            string conStr = GetConStr(ExcelPath);

            if (string.IsNullOrEmpty(conStr))

                return null;
            OleDbConnection connection = new OleDbConnection(conStr);

            connection.Open();

            if (string.IsNullOrEmpty(SheetName))

                  SheetName = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null).Rows[]["TABLE_NAME"].ToString(); 
            else if (!SheetName.Contains("$"))

                  SheetName = SheetName + "$";
            OleDbDataAdapter adapter = new OleDbDataAdapter("select * from [" + SheetName + "]", conStr);

            DataSet dataSet = new DataSet();

            adapter.Fill(dataSet, "[" + SheetName + "$]");

            connection.Close();

            return dataSet.Tables[];

        }