帮助与理解C＃语法，同时调用一个新的Action [英] Help with understanding C# syntax while Invoking a new Action

问题描述

我是新的C＃和不了解调用新的动作，甚至一个动作是什么样的语法。从我的理解Port1_DataReceived，我要创建一个动作，因为我是在一个新的胎面......任何人都可以对我为什么要做这个解释一下？

I am new to c# and do not understand the syntax of invoking a new action or even what an action is. From my understanding in Port1_DataReceived, I have to create an action because I am in a new tread... Can anyone elaborate on why I need to do this?

public Form1()
{
    InitializeComponent();
    SerialPort Port1 = new SerialPort("COM11", 57600, Parity.None, 8, StopBits.One);
    Port1.DataReceived += new SerialDataReceivedEventHandler(Port1_DataReceived);
    Port1.Open();
}


private void Port1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
     SerialPort Port = (SerialPort)sender;
     string Line = "";
     int BytestoRead = Port.BytesToRead;
     Line = Port.ReadLine();
     label1.Invoke(new Action(() =>
     {
          label1.Text = Line;
      }));
}

中的代码剪断，我真的有麻烦的理解是：

The code snip that I am really having trouble understanding is:

label1.Invoke(new Action(() =>
         {
              label1.Text = Line;
          }));

有人能打破这个是什么做的，我确定它是没什么复杂的，只是我从来没有见过这样的事情。这是真正抱着我的语法是（）=> 新动作指向下面的代码什么的？

Can someone break down what this is doing.. I am sure it is nothing to complicated, just that I have never seen anything like it before. The syntax that is really holding me up is ()=> the new action is pointing to the code below or something??

推荐答案

这使用了一种名为lambda表达式创建的行动构造预期签名匹配匿名委托。

This uses something known as a "lambda expression" to create an anonymous delegate that matches the signature expected by the Action constructor.

您能够达到这样的效果相同：

You could achieve the same effect like this:

label1.Invoke(SetText);
...
public void SetText() { label1.Text = Line; }

或像这样的：

label1.Invoke(new Action(SetText));
...
public void SetText() { label1.Text = Line; }

或像这样的：

label1.Invoke(new Action(delegate() { label1.Text = Line; }));

或像这样的：

label1.Invoke(delegate() { label1.Text = Line; });

或像这样的：

label1.Invoke(() => label1.Text = Line);

这些大多只是语法快捷方式，以方便代表一个动作。

These are mostly just syntactic shortcuts to make it easier to represent an action.

需要注意的是lambda表达式经常有参数。当只有一个参数，括号是可选的：

Note that lambda expressions often have parameters. When there is only one parameter, the parentheses are optional:

list.ToDictionary(i => i.Key);

在没有参数或多个参数，括号是必需的，使其明显的你在做什么这样做。因此，（）=方式>

When there are no parameters or multiple parameters, the parentheses are necessary to make it obvious what you're doing. Hence, the () =>.

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