string is nog recognized as a valid DateTime

Question

HI i made the followin class to get dates from an excel file.

 

file:

        col:a      col:b                      col:c 

1.   X-mas      2015-19-12         2016-03-01 

2.  carnaval   2016-20-02         2016-28-02

 

using System;
using OfficeOpenXml;
using System.IO;


namespace CalviVsTribessCheck.Cmd
{
    public static class ExcelFileDataAccess
    {
        public static void ReadExcelFile(DateTime start)
        {
            var filePath = @"c:\code\Tools\Development\RtcMonitoring\RatingTribessCheck.Cmd\Vacations.xlsx";
            var sheetName = "vacations";
            using (var excelPkg = new ExcelPackage())
            using (var stream = new FileStream(filePath, FileMode.Open))
            {
                excelPkg.Load(stream);
                ExcelWorksheet oSheet = excelPkg.Workbook.Worksheets[sheetName];

                var totalRows = oSheet.Dimension.End.Row;

                for (var i = 1; i <= totalRows; i++)
                {

                    var vacationbegindate = DateTime.Parse((oSheet.Cells[i, 1]).Value.ToString());
                    var vacationenddate = DateTime.Parse((oSheet.Cells[i, 2]).Value.ToString());

                    BusinessLogic.CheckVacation(start, vacationbegindate, vacationenddate);

                }
            }
        }








    }
}

however i get the following error when converting a cell value to a dateTime:

 

 The string is not recognized as a valid DateTime. Index 0 begins with an unknown word

 

How can i fix this ???? please provide me with your answer