求帮，关于C# WinForm dataGridView中点一个Button新增加一行代码编写？？

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Data.SqlClient;

using System.Drawing;

using System.Text;

using System.Windows.Forms;



namespace DataSource

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }



        private DataSet ds = new DataSet();

        private SqlConnection conn = null;

        private SqlDataAdapter da = null;

        private const string DRIVER = "server=.;database=northwind;uid=sa;pwd=sa";

        private const string sql_select = "select * from region";



        /**

         * 此方法为将数据库northwind中的region表的数据查询出来并放入DataSet中 

        **/ 

        private void Form1_Load(object sender, EventArgs e)

        {

            conn = new SqlConnection(DRIVER);

            da = new SqlDataAdapter(sql_select,conn);

            da.Fill(ds,"table");

            this.dataGridView1.DataSource = ds.Tables["table"].DefaultView;

        }



        private bool BtnInsert() //此方法作用于添加

        {

            da.InsertCommand = conn.CreateCommand();

            da.InsertCommand.CommandText = "insert into region values(@id,@ption)";

            da.InsertCommand.Parameters.Add("@id", SqlDbType.Int, 4, "regionid");

            da.InsertCommand.Parameters.Add("@ption", SqlDbType.VarChar, 10, "regiondescription");

            int count = da.Update(ds);

            bool result = count > 0 ? true : false;

            return result;

        }

        private void button1_Click(object sender, EventArgs e)

        {

            if (this.BtnInsert())//调用此方法

            {

                MessageBox.Show("添加成功!");

            }

            else 

            {

                MessageBox.Show("添加失败!");

            }

        }





        private bool BtnDelect() //此方法作用于删除

        {

            SqlParameter sp = new SqlParameter();

            da.DeleteCommand = conn.CreateCommand();

            da.DeleteCommand.CommandText = "delete region where regionid=@id";

            sp = da.DeleteCommand.Parameters.Add("@id", SqlDbType.Int, 4, "regionid");

            sp.SourceVersion = DataRowVersion.Original;

            ds.Tables["table"].Rows[this.dataGridView1.CurrentRow.Index].Delete();

            int count = da.Update(ds);

            bool result = count > 0 ? true : false;

            return result;

        }

        private void button2_Click(object sender, EventArgs e)

        {

            if (this.BtnDelect())//调用删除方法

            {

                MessageBox.Show("删除成功!");

            }

            else

            {

                MessageBox.Show("删除失败!");

            }

        }





        private bool BtnUpdate() //此方法作用于修改

        {

            SqlParameter sp = new SqlParameter();

            da.UpdateCommand = conn.CreateCommand();

            da.UpdateCommand.CommandText = "update region set regionid=@id,regiondescription=@ption where regionid=@oldid";



            da.UpdateCommand.Parameters.Add("@id", SqlDbType.Int, 4, "regionid");

            da.UpdateCommand.Parameters.Add("@ption", SqlDbType.VarChar, 10, "regiondescription");



            sp = da.UpdateCommand.Parameters.Add("@oldid", SqlDbType.Int, 4, "regionid");

            sp.SourceVersion = DataRowVersion.Original;

            

            int count = da.Update(ds);

            bool result = count > 0 ? true : false;

            return result;

        }

        private void button3_Click(object sender, EventArgs e)

        {

            if (this.BtnUpdate())//调用修改方法

            {

                MessageBox.Show("修改成功!");

            }

            else

            {

                MessageBox.Show("修改失败!");

            }

        }





    }

}