protected void btnUpload_Click(object sender, EventArgs e)
    {
        if (fileUpload.HasFile)
        {
            if (Path.GetExtension(fileUpload.FileName) == ".xlsx")
            {
                ExcelPackage package = new ExcelPackage(fileUpload.FileContent);
                DataTable    dt      = package.ToDataTable();


                List <shift> toInsert = new List <shift>();
                foreach (DataRow row in dt.Rows)
                {
                    shift toAdd = new shift();
                    toAdd.ShiftName = row["ShiftName"].ToString();
                    toAdd.From      = Convert.ToDateTime(row["Start_time"]);
                    toAdd.To        = Convert.ToDateTime(row["End_time"]);
                    toAdd.DayName   = row["DayOfWeek"].ToString();
                    toAdd.UserName  = row["username"].ToString();
                    toInsert.Add(toAdd);
                }



                ShiftController.InsertShifts(toInsert);

                bindGrid();
            }
        }
    }