我无法并排更新两个Excel文件

Question

通过单击“同步”按钮，我们将收集2个表的库存号并将它们打印在第1个表的库存号上。

我有两个并排的excel文件，我无法更新它们 （添加+转移）。

同步

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using Excel;
using Microsoft.Office.Core;

namespace WindowsFormsApp3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        DataSet ds;
        DataSet ds2;
        OpenFileDialog of;
        OpenFileDialog ofl;
        FileStream fs;
        FileStream fst;
        IExcelDataReader okuyucu;
        IExcelDataReader okuyucu1;
        DataTable dt;
        DataTable dts;
        DataRow new_data_row;
        int adet;
        int adet2;
        int StokNo1;
        int StokNo2;


        private void button3_Click(object sender, EventArgs e)//Synchronize Button
        {
            int Adet = Int32.Parse(dataGridView1.Columns[2].Index.ToString());
            int Adet2 = Int32.Parse(dataGridView2.Columns[2].Index.ToString());
            int StokNo1 = Int32.Parse(dataGridView1.Columns[0].Index.ToString());
            int StokNo2 = Int32.Parse(dataGridView2.Columns[0].Index.ToString());


            foreach (DataTable dt in ds.Tables)
            {
                for (int i = 0; i < ds.Tables.Count; i++)
                {
                    StokNo1 = Int32.Parse(dataGridView1.Columns[0].Index.ToString());//The StokNo belonging to DataGridWiew1.
                    Adet = Int32.Parse(dataGridView1.Columns[2].Index.ToString());//The number belonging to DataGridWiew1.

                }
            }


            foreach (DataTable dt2 in ds2.Tables)
            {
                for (int j = 0; j < ds2.Tables.Count; j++)
                {
                    StokNo2 = Int32.Parse(dataGridView2.Columns[0].Index.ToString());//The StokNo belonging to DataGridWiew2.
                    Adet2 = Int32.Parse(dataGridView2.Columns[2].Index.ToString());//The number belonging to DataGridWiew2.
                }
            }

            if ((StokNo1 == StokNo2))//StokNo is Equal
            {
                for (int i = 0; i < dataGridView2.Rows.Count; i++)
                {
                    int toplam = adet + adet2;
                    ds.Tables[0].Rows.Add(toplam);
                }


            }
            else
            {
                ds.Tables[0].Rows.Add();//If stokno is not equal add to the last listed
            }

        }




        private void button4_Click(object sender, EventArgs e)
        {
            SaveFileDialog save = new SaveFileDialog();
            save.Filter = "Excel|*.xls";
            save.OverwritePrompt = true;
            save.CreatePrompt = true;

            if (save.ShowDialog() == DialogResult.OK)
            {
                StreamWriter kayıt = new StreamWriter(save.FileName);
                kayıt.WriteLine(dataGridView1.ToString());
                kayıt.Close();
            }
        }
    }
}

如果库存编号等于添加到列表中，我想根据库存编号更新编号，如果库存编号不同，则在末尾添加它。