private async void button1_Click(object sender, EventArgs e)
        {
            melsec_net.IpAddress = textBox1.Text;
            if (!int.TryParse(textBox2.Text, out int port))
            {
                MessageBox.Show(DemoUtils.PortInputWrong);
                return;
            }

            melsec_net.Port = port;
            melsec_net.ConnectClose( );

            button1.Enabled = false;
            OperateResult connect = await melsec_net.ConnectServerAsync( );

            if (connect.IsSuccess)
            {
                MessageBox.Show(HslCommunication.StringResources.Language.ConnectedSuccess);
                button2.Enabled = true;
                button1.Enabled = false;
                panel2.Enabled  = true;
                userControlReadWriteOp1.SetReadWriteNet(melsec_net, "D100", true);
            }
            else
            {
                MessageBox.Show(connect.Message);
                button1.Enabled = true;
            }
        }