ChangeGoodInOrderForm

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

namespace WindowsFormsApp2
{
    public partial class ChangeGoodInOrderForm : Form
    {
        NpgsqlConnection con;
        private DataSet ds = new DataSet();
        private DataTable dt = new DataTable();
        SqlDataReader dr;
        NpgsqlDataAdapter da;
        int id;
        int goodID, orderID;
        private void Update()
        {
            string sql = "Select * from goods";
            da = new NpgsqlDataAdapter(sql, con);
            ds.Reset();
            da.Fill(ds);
            dt = ds.Tables[0];
            comboBoxGood.DataSource = dt;
            comboBoxGood.DisplayMember = "name";
            comboBoxGood.ValueMember = "goodID";
            comboBoxGood.SelectedValue = goodID.ToString();

        }
        public ChangeGoodInOrderForm(NpgsqlConnection con, int id, int orderID, int goodID, int amount)
        {
            InitializeComponent();
            this.con = con;
            this.id = id;
            this.orderID = orderID;
            this.goodID = goodID;
            textBoxAmount.Text = amount.ToString();

        }

        private void buttonSave_Click(object sender, EventArgs e)
        {
            //try
            //{
                NpgsqlCommand command = new NpgsqlCommand("UPDATE orderEntries SET orderID = :orderID, goodID = :goodID, " +
                    "amount = :amount WHERE orderEntriesID = :id", con);
                command.Parameters.AddWithValue("id", id);
                command.Parameters.AddWithValue("orderID", orderID);
                command.Parameters.AddWithValue("goodID", comboBoxGood.SelectedValue);
                command.Parameters.AddWithValue("amount", Convert.ToInt32(textBoxAmount.Text));
                command.ExecuteNonQuery();
                Close();
            //}
            //catch { }
        }

        private void ChangeGoodInOrderForm_Load(object sender, EventArgs e)
        {
            Update();
        }

        private void ChangeGoodInOrderForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            Close();
        }
    }
}