问EPPLUS excel新增数据保存失败？

using System.Windows.Forms;
using OfficeOpenXml;
using OfficeOpenXml.Style;
using System.Drawing;
using System.Data;
using System;
using System.IO;
using System.Threading;

namespace WindowsFormsApp1
{
    public class ExcelExport
    {    
        //传入一个excel文件路径和一个字符串数组，把数组追加到excel
        public ExcelExport(string filePath, string[] strlist)
        {
            //打开文件
            using (FileStream file = new FileStream(filePath, FileMode.OpenOrCreate))
            {
                ExcelPackage package = new ExcelPackage(file);


                ExcelWorksheet worksheet;
                //判断是新建还是打开
                try
                {
                    worksheet = package.Workbook.Worksheets[1];
                }

                catch
                {
                    worksheet = package.Workbook.Worksheets.Add("Sheet1");
                }
                
                //如果表是空的，从第一行开始写
                if (worksheet.Dimension == null)
                {
                    for (int i = 0; i < strlist.Length; i++)
                    {
                        worksheet.Cells[1, i + 1].Value = strlist[i];
                    }
                    
                    //这里能正常保存
                    package.Save();
                    return;

                }
                //如果表里有数据，就写到数据的下一行
                int row = worksheet.Dimension.End.Row;
                for (int i = 0; i < strlist.Length; i++)
                {
                    worksheet.Cells[row + 1, i + 1].Value = strlist[i];

                }
                //这里就不行了
                package.Save();
 
                
            }
        }

    }
}