net - Action< T>委托的错误

Question

我使用Action<T> Delegate使类和表单之间的链接。类连接到串口，接收到的数据显示在表单中。Action<T> Delegate在表单中封装了一个方法来显示接收到的数据。但是委托总是显示null，没有封装方法。

类代码为:

 public SerialPort mySerialPort;
    public Action<byte[]> DataReceived_Del;             //delegate for data recieved
    public string connect()
    {
        try
        {
            mySerialPort = new SerialPort("COM14");
            mySerialPort.BaudRate = 115200;
            mySerialPort.DataBits = 8;
            mySerialPort.Parity = System.IO.Ports.Parity.None;
            mySerialPort.StopBits = System.IO.Ports.StopBits.One;
            mySerialPort.RtsEnable = false;
            mySerialPort.DataReceived += mySerialPort_DataReceived;
            mySerialPort.Open();
        }
        catch (SystemException ex)
        {
            MessageBox.Show(ex.Message);
        }
        if (mySerialPort.IsOpen)
        {
            return "Connected";
        }
        else
        {
            return "Disconnected";
        }
    }

    //serial port data recieved handler
    public void mySerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
    {
        try
        {
            //no. of data at the port
            int ByteToRead = mySerialPort.BytesToRead;
            //create array to store buffer data
            byte[] inputData = new byte[ByteToRead];
            //read the data and store
            mySerialPort.Read(inputData, 0, ByteToRead);

            var copy = DataReceived_Del;
            if (copy != null) copy(inputData); 
        }
        catch (SystemException ex)
        {
            MessageBox.Show(ex.Message, "Data Received Event");
        }
    }

在我们显示数据的表单中:

 public Form1()
    {
        InitializeComponent();
        Processes newprocess = new Processes();
        newprocess.DataReceived_Del += Display;

    }
    //Display
    public void Display(byte[] inputData)
    {
        try
        {
            Invoke(new Action(() => TboxDisp.AppendText((BitConverter.ToString(inputData)))));
        }
        catch (SystemException ex)
        {
            MessageBox.Show(ex.Message, "Display section");
        }
    }

DataReceived_Del应该封装方法Display，但它是NULL。

我看不出发生了什么事。

Answer 1

你应该在构造函数之外定义newprocess，这可能会解决

Processes newprocess;
public Form1()
{
    InitializeComponent();
    newprocess = new Processes();
    newprocess.DataReceived_Del += Display;

}

Answer 2

您正在使用+=添加到委托，但委托是NULL开始。我不确定那是否有效。我想试试=而不是+=。

public Form1() {
    InitializeComponent();
    Processes newprocess = new Processes();
    newprocess.DataReceived_Del = Display;
}