C# SerialPort DataReceived 事件未更新主 UI

Question

我目前正在开发一个完全用 c# 编写的防盗报警解决方案。该程序与基于 USB 串行端口的 IO 板通信，该 IO 板具有硬连线的警报传感器。我遇到了一个问题，即 DataReceived 事件无法更新主 UI，除非我从 DataReceived 事件中调用一个名为 TextLog 的子（见末尾）。奇怪的是，来自查询区域 1 的 DataReceived 事件能够更新主 UI，但不能更新区域 2 或 3。此外，如果我在执行串行端口写入的行插入断点，它会按预期工作。

值得一提的是这些全局变量：

string ioCardRxString = "";

bool[] arrGlobalZoneStatus = new bool[4];

通过从设置文件中读取设置来打开串口（一切正常）。

private void OpenIOComPort()
    {
        bool error = false;

        else
        {
            // Set the port's settings
            spIOCard.PortName = Settings1.Default.ioComPort;
            spIOCard.BaudRate = int.Parse(Settings1.Default.ioBaudRate);
            spIOCard.DataBits = int.Parse(Settings1.Default.ioDataBits);
            spIOCard.StopBits = (System.IO.Ports.StopBits)Enum.Parse(typeof(System.IO.Ports.StopBits), Settings1.Default.ioStopBits);
            spIOCard.Parity = (System.IO.Ports.Parity)Enum.Parse(typeof(System.IO.Ports.Parity), Settings1.Default.ioParity);
            spIOCard.Handshake = (System.IO.Ports.Handshake)Enum.Parse(typeof(System.IO.Ports.Handshake), Settings1.Default.ioHandshake);

            try
            {
                // Open the port
                spIOCard.Open();
            }
            catch (UnauthorizedAccessException) { error = true; }
            catch (System.IO.IOException) { error = true; }
            catch (ArgumentException) { error = true; }

            //On error, advise the user
            if (error)
            {
                MessageBox.Show("Could not open the I/O Board COM port.");                    
                globalIOCardError = true;
            }

            if (!error)
            {
                globalIOCardError = false;
                // Do Nothing
            }

        }
    }

定时器每 500 毫秒运行一次，它向串口写入 3 条命令，每条命令之间相隔 25 毫秒（硬件限制）。这些命令查询 IO 板以确定每个警报传感器的状态。

private void tmrAuditSensors_Tick(object sender, EventArgs e) 
    {
        try
        {
            if (globalIOCardError == false && Settings1.Default.disableSensorAudit == false)
            {
                if (Settings1.Default.zone1Armed == true)
                {
                    spIOCard.Write("~in01~");
                    System.Threading.Thread.Sleep(25);;
                }

                if (Settings1.Default.zone2Armed == true)
                {
                    spIOCard.Write("~in02~");
                    System.Threading.Thread.Sleep(25);;
                }

                if (Settings1.Default.zone3Armed == true)
                {
                    spIOCard.Write("~in03~");
                    System.Threading.Thread.Sleep(25);;
                }

                //Applicable results will appear on serial data received event
            }
        }
        catch
        {
            textLog("There was a problem writing to the serial port, check and restart app");
            emergencyHalt();
        }
    }

串行端口 DataReceived 事件读取返回的字符串并写入全局布尔数组。如果该区域打开 (=1)，则为 True，如果该区域关闭 (=0)，则为 False。注意：星号线。

private void spIO_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
    {
        ioCardRxString = spIOCard.ReadExisting();
        textLog(ioCardRxString); //*Cannot make it work without this

        if (ioCardRxString.Contains("in05=1") == true)
        {
            arrGlobalZoneStatus[1] = true;
        }

        if (ioCardRxString.Contains("in05=0") == true)
        {
            arrGlobalZoneStatus[1] = false;
        }

        if (ioCardRxString.Contains("in01=1") == true)
        {
            arrGlobalZoneStatus[2] = true;
        }

        if (ioCardRxString.Contains("in01=0") == true)
        {
            arrGlobalZoneStatus[2] = false;
        }

        if (ioCardRxString.Contains("in17=1") == true)
        {
            arrGlobalZoneStatus[3] = true;
        }

        if (ioCardRxString.Contains("in17=0") == true)
        {
            arrGlobalZoneStatus[3] = false;
        }

    }

另外，另一个计时器会定期（每 250 毫秒）检查每个数组成员的内容，然后相应地通过一些颜色更改和文本更新来更新主 UI。

 private void tmrCheckZoneStatus_Tick(object sender, EventArgs e)
    {
        if (arrGlobalZoneStatus[1] == true)
        {
            button10.BackColor = System.Drawing.Color.Red;
            textLog(button10.Text + " was activated");

            if (globalFullAlarmSet || globalNightAlarmSet || globalDoorsAlarmSet)
            {
                this.BeginInvoke(new EventHandler(delegate { checkAndActivateRelays(1); }));
            }
        }

        if (arrGlobalZoneStatus[1] == false)
        {
            button10.BackColor = System.Drawing.Color.Gray;
        }

        if (arrGlobalZoneStatus[2] == true)
        {
            button11.BackColor = System.Drawing.Color.Red;
            textLog(button11.Text + " was activated"); ;

            if (globalFullAlarmSet || globalNightAlarmSet || globalDoorsAlarmSet)
            {
                this.BeginInvoke(new EventHandler(delegate { checkAndActivateRelays(2); }));
            }
        }

        if (arrGlobalZoneStatus[2] == false)
        {
            button11.BackColor = System.Drawing.Color.Gray;
        }

        if (arrGlobalZoneStatus[3] == true)
        {
            button12.BackColor = System.Drawing.Color.Red;
            textLog(button12.Text + " was activated");

            if (globalFullAlarmSet || globalNightAlarmSet || globalDoorsAlarmSet)
            {
                this.BeginInvoke(new EventHandler(delegate { checkAndActivateRelays(3); }));
            }
        }

        if (arrGlobalZoneStatus[3] == false)
        {
            button12.BackColor = System.Drawing.Color.Gray;
        }

    }

textLog 子：

public void textLog(string logEntry)
    {
        textLines++;
        try
        {
            if (this.txtLog.InvokeRequired)
            {
                ChangeTextCallback MethodCallback = new ChangeTextCallback(textLog);
                this.Invoke(MethodCallback, new object[] { logEntry });
            }
            else
            {
                if (!logEntry.Contains("?"))
                {
                    txtLog.Text = txtLog.Text + DateTime.Now + " >: " + logEntry + "\r\n";
                    txtLog.SelectionStart = txtLog.Text.Length;
                    txtLog.ScrollToCaret();

                    if (textLines > 3000)
                    {
                        txtLog.Clear();
                        textLines = 0;
                        textLog("Text log cleared");
                    }

                    System.IO.StreamWriter sw = new System.IO.StreamWriter(logFile, true);
                    try
                    {
                        sw.WriteLine(DateTime.Now + " >: " + logEntry);
                    }
                    catch (Exception ex)
                    {
                        //
                    }

                    sw.Close();
                }
            }
        }
        catch
        {
            //
        }


    }

我想我需要在某个地方合并调用/委托，但作为一个菜鸟，我有点摸不着头脑。我们将不胜感激。

谢谢

Answer 1

我没有通读所有内容，但这应该会让你走上正确的道路：

SerialPort.DataReceived 事件在单独的线程上引发。如果您需要异步处理数据的接收，并在其上使用 GUI 执行某些操作，您可以执行以下操作：

private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e) {
    var port = (SerialPort)sender;
    string data = port.ReadExisting();

    UpdateGui(data);
}

private void UpdateGui(string data) {
    if (this.InvokeRequired) {
        this.Invoke(new Action( d => UpdateGui(d) ));
        return;
    }

    this.txtBox1.Text = data;
}

现在，就是说.... 你真的想使用DataReceived吗？听起来你（主机）正在启动与外部板的所有通信。如果是这种情况，那么我建议您改用同步（阻塞）读取：

1. Write the request out the port
2. Call read() with the expected number of bytes
3. Process the reply.