Hello guys, how give a message box code after progress bar complete?

private void button2_Click(object sender, EventArgs e)
        {
            for (int i = 0; i < dataGridView1.Rows.Count; i++)             
            {
                MySqlConnection con = new MySqlConnection(@"Data Source=localhost; Database=nigol; User ID=**; Password=**");
                MySqlCommand cmd = new MySqlCommand("INSERT INTO masterlist (PROBER_ID,IP_ADDRESS,LEVEL) values (@PROBER_ID,@IP_ADDRESS,@LEVEL)", con);
                //string InsertString = @"IF NOT EXISTS (SELECT * FROM from nigol.masterlist WHERE PROBER_ID, IP_ADDRESS, LEVEL = @PROBER_ID, @IP_ADDRESS, @LEVEL)";                
                cmd.Parameters.AddWithValue("@PROBER_ID", dataGridView1.Rows[i].Cells[0].Value);
                cmd.Parameters.AddWithValue("@IP_ADDRESS", dataGridView1.Rows[i].Cells[1].Value);
                cmd.Parameters.AddWithValue("@LEVEL", dataGridView1.Rows[i].Cells[2].Value);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
                {                   
                    progressBar1.Maximum = dataGridView1.Rows.Count;
                    progressBar1.Value = i;            
                }
                            
            }
    }