Question

我正在尝试使用DataReceived事件，但无法从方法OnDataReceived()调用我的方法Main()。我通过添加行System.Windows.Forms.Application.Exit();来证明这一点，这将有效地关闭窗体应用程序;但事实并非如此。

基本上我只想在通过串口接收数据时运行方法OnDataReceived。我希望用arduino.DataReceived += OnDataReceived;做到这一点，但事实证明这是不成功的。请随意查看我的评论以获得指导。此外，我在任何方法之外引入了字符串received和串行端口arduino，这是否会影响功能？

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }

    string received;
    private SerialPort arduino;

    private void button2_Click(object sender, EventArgs e)
    {
        comboBox1.Items.Clear();
        string[] ports = SerialPort.GetPortNames();
        foreach (string port in ports)
        {
            comboBox1.Items.Add(port);
        }
        comboBox1.SelectedIndex = 0;
    }

    private void Main(string port)
    {
        using (arduino = new SerialPort(port))
        {
            arduino.Open();
            arduino.DtrEnable = true;
            arduino.RtsEnable = true;
            arduino.BaudRate = 9600;

            arduino.DataReceived += OnDataReceived; //when data is received, call method below.

            //System.Windows.Forms.Application.Exit(); //this works, which means the above line has been run too.
        }
    }

    private void OnDataReceived(object sender, SerialDataReceivedEventArgs e) //this method does not get called from the above method.
    {
        System.Windows.Forms.Application.Exit();
        received = arduino.ReadLine();
    }

    public void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        Main(comboBox1.Text);
        if (checkBox1.Checked)
        {
            checkBox1.Text = "Listening...";
                if (received == "S\r")
                {
                    arduino.Close();
                    //System.Diagnostics.Process.Start("shutdown", "/f /r /t 0");
                    //System.Windows.Forms.Application.Exit();
                }
        }
        else
        {
            checkBox1.Text = "Start";
        }

        }
    }
}

Answer 1

您的一个问题是using阻止：

using (arduino = new SerialPort(port))
{
    arduino.Open();
    arduino.DtrEnable = true;
    arduino.RtsEnable = true;
    arduino.BaudRate = 9600;

    arduino.DataReceived += OnDataReceived; //when data is received, call method below.

    //System.Windows.Forms.Application.Exit(); //this works, which means the above line has been run too.
}

执行代码时arduino.Dispose被调用，SerialPort消失，事件注册也被遗忘。因此，您的活动永远不会被解雇。

检查您的活动是否有效。在调试器中使用breakpoint。

编辑：

null值表示它已取消注册。由于SerialPort已被处置。

基本上我只想在通过串口接收数据时运行OnDataReceived方法。

问题是你没有运行这种方法。它被设计（与任何其他event一样）在需要时被触发。因此，它将帮助您保持被动，并且您的GUI可以保持响应（因为您不必主动运行它）。

SerialPort可以在打开时写入和读取。因此，如果您想监控它，只需打开它，注册参加活动并等待看看会发生什么。

public void checkBox1_CheckedChanged(object sender, EventArgs e)
{

    if (checkBox1.Checked)
    {

        arduino = new SerialPort(port);

        // you should specify these before opening the port
        arduino.DtrEnable = true;
        arduino.RtsEnable = true;
        arduino.BaudRate = 9600;

        // register to the event
        arduino.DataReceived += OnDataReceived;
        //open the port
        arduino.Open();

        // tell the user
        checkBox1.Text = "Listening...";
    }                
}

在事件中，您应该指定数据到达时您想要执行的操作：

private void OnDataReceived(object sender, SerialDataReceivedEventArgs e) //this method does not get called from the above method.
{
    // first of all read out what you have received!
    received = arduino.ReadLine();
    // do something with the information

    // if you have a condition and really want to close the application or shut down the computer
   // first close the port!!!
   arduino.Close();

}

您的旧版本：

    System.Windows.Forms.Application.Exit();
    received = arduino.ReadLine();

可能无效。这就像关闭你身后的门，然后试着拿起仍在你的封闭式公寓里的手机......

如何使用串行端口DataReceived事件调用方法

1 个答案: