private void button5_Click(object sender, EventArgs e) { // 启动串口 if (busTcpServer != null) { try { busTcpServer.StartModbusRtu(textBox10.Text); button5.Enabled = false; } catch (Exception ex) { MessageBox.Show("Start Failed:" + ex.Message); } } else { MessageBox.Show("Start tcp server first please!"); } }