C#_JAN_1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.OleDb;

namespace TestDatabaseApp_5
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

        }
        private DataTable dt = new DataTable();
        private int cnt = 0;
        private DataSet ds = new DataSet();

        private void Btn1_Click(object sender, EventArgs e)
        {

        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.ActiveControl = this.txtBox1;


        }

        private void txtBox1_TextChanged(object sender, EventArgs e)
        {
            OleDbConnection conn = new OleDbConnection();
            OleDbCommand comm = new OleDbCommand();
            long LJAN;
            LJAN = Convert.ToInt64(txtBox1.Text);
            LJAN = long.Parse(txtBox1.Text);
            int len;
            len = (LJAN == 0) ? 1 : ((int)Math.Log10(LJAN) + 1);

            conn.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\user2\Documents\Documents\TestData_2.accdb"; // MDB名など
            dataGridView1.AutoGenerateColumns = false;
            DataGridViewColumn column = new DataGridViewTextBoxColumn();
            // 接続します。
            conn.Open();

            // SELECT文を設定します。
            comm.CommandText = "SELECT * FROM test_data";
            comm.Connection = conn;
            OleDbDataAdapter oda = new OleDbDataAdapter();
            oda.SelectCommand = comm;
            // 結果を表示します。
            //DataSet ds = new DataSet();
            oda.Fill(ds, "data");
            DataView dv = new DataView();
            if (len == 13)
            {

                dv = new DataView(ds.Tables[0], "id=" + LJAN, null, DataViewRowState.CurrentRows);
                cnt += 1;

                dataGridView1.DataSource = dv;

                dataGridView1.Columns[3].DataPropertyName = "price";
                dataGridView1.Columns[1].DataPropertyName = "name";

                // 接続を解除します。
                DataRowView dtrv = dv.AddNew();

                conn.Close();

                //dataGridView1.DataSource = null;
            }
            if (len >= 13)
            {
                txtBox1.SelectAll();
            }
        }

    }
}