private void button2_Click( object sender, EventArgs e )
 {
     // 断开连接
     melsecSerial.Close( );
     button2.Enabled = false;
     button1.Enabled = true;
     panel2.Enabled = false;
 }
        private void button1_Click( object sender, EventArgs e )
        {
            if (!int.TryParse( textBox2.Text, out int baudRate ))
            {
                MessageBox.Show( "波特率输入错误!" );
                return;
            }

            if (!int.TryParse( textBox16.Text, out int dataBits ))
            {
                MessageBox.Show( "数据位输入错误!" );
                return;
            }

            if (!int.TryParse( textBox17.Text, out int stopBits ))
            {
                MessageBox.Show( "停止位输入错误!" );
                return;
            }

            melsecSerial?.Close( );
            melsecSerial = new MelsecSerial( );

            try
            {
                melsecSerial.SerialPortInni( sp =>
                {
                    sp.PortName = textBox1.Text;
                    sp.BaudRate = baudRate;
                    sp.DataBits = dataBits;
                    sp.StopBits = stopBits == 0 ? System.IO.Ports.StopBits.None : (stopBits == 1 ? System.IO.Ports.StopBits.One : System.IO.Ports.StopBits.Two);
                    sp.Parity = comboBox1.SelectedIndex == 0 ? System.IO.Ports.Parity.None : (comboBox1.SelectedIndex == 1 ? System.IO.Ports.Parity.Odd : System.IO.Ports.Parity.Even);
                } );
                melsecSerial.Open( );

                button2.Enabled = true;
                button1.Enabled = false;
                panel2.Enabled = true;
            }
            catch (Exception ex)
            {
                MessageBox.Show( ex.Message );
            }
        }