C# Access Update Nasıl Yapılır?

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 CrudApplication
{
    public partial class Form1 : Form
    {
        OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=CrudApp.mdb");
        OleDbCommand cmd;
        OleDbDataAdapter da;
        public int id;
        public Form1()
        {
            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)
        {
            showInformation();
        }
        public void showInformation()
        {
            try
            {
                conn.Open();
                da = new OleDbDataAdapter("select * from Users", conn);
                DataSet ds = new DataSet();
                da.Fill(ds, "Users");
                dataGridView1.DataSource = ds.Tables["Users"];
                conn.Close();
                dataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
            }
        }

        private void buttonAdd_Click(object sender, EventArgs e)
        {
            try
            {
                conn.Open();
                cmd = new OleDbCommand("insert into Users(uName,uSurname,uGender,uBorn,uPhone,uHobi) values(@name,@surname," +
                    "@gender,@born,@phone,@hobi)", conn);
                cmd.Parameters.AddWithValue("@name", textBoxName.Text.ToString());
                cmd.Parameters.AddWithValue("@surname", textBoxSurname.Text.ToString());
                if (radioButtonMale.Checked == true)
                    cmd.Parameters.AddWithValue("@gender", radioButtonMale.Text.ToString());
                else
                    cmd.Parameters.AddWithValue("@gender", radioButtonFemale.Text.ToString());
                cmd.Parameters.AddWithValue("@born", dateTimePicker1.Value.ToString());
                cmd.Parameters.AddWithValue("@phone", textBoxPhone.Text.ToString());
                cmd.Parameters.AddWithValue("@hobi", comboBox1.SelectedItem.ToString());
                cmd.ExecuteNonQuery();
                conn.Close();
                showInformation();
                textBoxName.Clear();
                textBoxSurname.Clear();
                textBoxPhone.Clear();
                radioButtonFemale.Checked = false;
                radioButtonMale.Checked = false;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
            }
        }

        private void buttonDelete_Click(object sender, EventArgs e)
        {

            try
            {
                conn.Open();
                cmd = new OleDbCommand("delete from Users where ID=@id", conn);
                cmd.Parameters.AddWithValue("@id", id);
                cmd.ExecuteNonQuery();
                conn.Close();
                showInformation();

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
            }
        }

        private void buttonUpdate_Click(object sender, EventArgs e)
        {
            if (id != 0)
            {
                try
                {
                    conn.Open();
                    string sql = "UPDATE Users SET uName = @name , uSurname = @surname,uGender = @gender,uBorn = @born,uPhone = @phone,uHobi = @hobi where ID=@id";
                    cmd = new OleDbCommand(sql, conn);
                    cmd.Parameters.AddWithValue("@id", id);
                    cmd.Parameters.AddWithValue("@name", textBoxName.Text.ToString());
                    cmd.Parameters.AddWithValue("@surname", textBoxSurname.Text.ToString());
                    if (radioButtonMale.Checked == true)
                        cmd.Parameters.AddWithValue("@gender", radioButtonMale.Text.ToString());
                    else
                        cmd.Parameters.AddWithValue("@gender", radioButtonFemale.Text.ToString());
                    cmd.Parameters.AddWithValue("@born", dateTimePicker1.Value.ToString());

                    cmd.Parameters.AddWithValue("@phone", textBoxPhone.Text.ToString());
                    cmd.Parameters.AddWithValue("@hobi", comboBox1.SelectedItem.ToString());
                    cmd.ExecuteNonQuery();
                    conn.Close();
                    showInformation();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message.ToString());
                }
            }
            else
                MessageBox.Show("Select record");

        }

        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            DataGridViewRow row = dataGridView1.Rows[e.RowIndex];
            id = Convert.ToInt32(row.Cells[0].Value);
            textBoxName.Text = Convert.ToString(row.Cells[1].Value);
            textBoxSurname.Text = Convert.ToString(row.Cells[2].Value);
            string gender = Convert.ToString(row.Cells[3].Value);
            if (gender == "Male")
                radioButtonMale.Checked = true;
            else
                radioButtonFemale.Checked = true;
            dateTimePicker1.Value = Convert.ToDateTime(row.Cells[4].Value);
            textBoxPhone.Text = Convert.ToString(row.Cells[5].Value);
            comboBox1.Text = Convert.ToString(row.Cells[6].Value);
        }
    }
}

private void buttonUpdate_Click(object sender, EventArgs e)
{
    try
    {
        conn.Open();
        string gender;
        if (radioButtonMale.Checked == true)
            gender = radioButtonMale.Text.ToString();
        else
            gender = radioButtonFemale.Text.ToString();

        cmd = new OleDbCommand("UPDATE Users SET uName=@name, uSurname=@surname, uGender=@gender, uBorn=@born, uPhone=@phone, uHobi=@hobi WHERE ID=@id", conn);
        cmd.Parameters.AddWithValue("@id", id);
        cmd.Parameters.AddWithValue("@name", textBoxName.Text.ToString());
        cmd.Parameters.AddWithValue("@surname", textBoxSurname.Text.ToString());
        cmd.Parameters.AddWithValue("@gender", gender);
        cmd.Parameters.AddWithValue("@born", dateTimePicker1.Value.ToString());
        cmd.Parameters.AddWithValue("@phone", textBoxPhone.Text.ToString());
        cmd.Parameters.AddWithValue("@hobi", comboBox1.SelectedItem.ToString());
        cmd.ExecuteNonQuery();
        conn.Close();
        showInformation();
        textBoxName.Clear();
        textBoxSurname.Clear();
        textBoxPhone.Clear();
        radioButtonFemale.Checked = false;
        radioButtonMale.Checked = false;
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message.ToString());
    }
}

private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
{
    id = Convert.ToInt32(dataGridView1.Rows[e.RowIndex].Cells[0].Value);
    textBoxName.Text = dataGridView1.Rows[e.RowIndex].Cells[1].Value.ToString();
    textBoxSurname.Text = dataGridView1.Rows[e.RowIndex].Cells[2].Value.ToString();
    string gender = dataGridView1.Rows[e.RowIndex].Cells[3].Value.ToString();
    if (gender == "Male")
        radioButtonMale.Checked = true;
    else
        radioButtonFemale.Checked = true;
    dateTimePicker1.Value = Convert.ToDateTime(dataGridView1.Rows[e.RowIndex].Cells[4].Value);
    textBoxPhone.Text = dataGridView1.Rows[e.RowIndex].Cells[5].Value.ToString();
    comboBox1.SelectedItem = dataGridView1.Rows[e.RowIndex].Cells[6].Value.ToString();
}