C#，串行端口的事件处理程序错误

Question

我正在为串行IO端口编写一个数据接收事件...以下是代码

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.IO;   //add namespaces
using System.IO.Ports;
     public class Program
        {

            //define a delegate class to handle DataReceived events
            internal delegate void SerialDataReceivedEventHanderDelegate(object sender,SerialDataReceivedEventArgs e);

            internal void DataReceived(object sender, SerialDataReceivedEventArgs e)
            {
                //place code to read and process data here
            }

            static void Main()
            {

                string myComPortName=null;
                //1. find available COM port
                string[] nameArray = null;
                nameArray = SerialPort.GetPortNames();
                if(nameArray.GetUpperBound(0)>0) {
                myComPortName = nameArray[0];  
                }
                else {
                    Console.WriteLine("Error");
                    return;
                }    

                //2. create a serialport object
                // the port object is closed automatically by use using()
                SerialPort myComPort = new SerialPort();

                myComPort.PortName = myComPortName; //the default paramit are 9600,no parity,one stop bit, and no flow control

                   private static SerialDataReceivedEventHandler SerialDataReceivedEventHandler1 =
                   new SerialDataReceivedEventHandler(ComPort.DataReceived);

                   myComPort.DataReceived+=SerialDataReceivedEventHandler1;


            }

        }

为什么在VS2010中，行： 私有静态 SerialDataReceivedEventHandler SerialDataReceivedEventHandler1 = new SerialDataReceivedEventHandler(ComPort.DataReceived);

正在向我展示： 1. 无效的表达术语“私人” 2. 修饰语“static”对该术语无效 3.我应该在这里使用Comport吗？或者只是 DataReceived...因为它的函数名称

感谢您的回复。

Answer 1

private 限定符仅适用于类定义中的成员（成员变量/方法）。 SerialDataReceivedEventHandler 只是方法内的一个变量。

Answer 2

private 和 static 在方法范围内无效。
您只能在类级别声明静态项 - 即此处：

public class Program
{
   private static object _memberField;

   private static void MemberMethod()
   {
     // not here:
     // private static object _insideMethod; // <- will not work
   }
}

Answer 3

不需要 private static，只需去 :-

var SerialDataReceivedEventHandler1 =
                   new SerialDataReceivedEventHandler(ComPort.DataReceived);

但如果您希望它成为 Program 类的成员，请将声明移出到 :-

   public class Program
        {

       private static SerialDataReceivedEventHandler;

那么您需要在 Main 中

SerialDataReceivedEventHandler1 =
                       new SerialDataReceivedEventHandler(ComPort.DataReceived);

，但更有可能的是，您确实想开始自己的类，因为“程序”并不是真正最好的地方......并且处理静态类和静态方法有点混乱

Answer 4

private 用于控制类型成员或类型本身的可访问性。它不适用于属于方法一部分的变量，因为方法本身已经最容易访问它。

此外，static 修饰符也无效。它还适用于类型的成员，以指示该成员是否是实例感知的。

你的台词：

private static SerialDataReceivedEventHandler SerialDataReceivedEventHandler1 =  
               new SerialDataReceivedEventHandler(ComPort.DataReceived);

应该是：

SerialDataReceivedEventHandler SerialDataReceivedEventHandler1 =  
               new SerialDataReceivedEventHandler(ComPort.DataReceived);  

但是，该台词一开始似乎完全没有必要。您可以将其简化为：

myComPort.DataReceived += ComPort.DataReceived;

Answer 5

该行位于 main 方法内部。私有和静态仅允许在方法之外。