C# 如何在c中生成从库到应用程序的回调（事件）#

我正在开发一个库（DLL），在这个库中，我需要向用户提供事件（中断），作为一种数据方法。库的工作是开始在套接字上列出，从套接字接收数据，并用一种方法将这些数据传递给用户

库：

public void start(string IP, int port)
{
    // start logic...

    // receives data from socket... send this data to user

}

Library. Class a = new Library. Class();
a.start(ip, port);

// I need this method called by library automatically when it receives data...

void receivedData(string data)
{
    // data which received by library....
}

应用程序：

public void start(string IP, int port)
{
    // start logic...

    // receives data from socket... send this data to user

}

Library. Class a = new Library. Class();
a.start(ip, port);

// I need this method called by library automatically when it receives data...

void receivedData(string data)
{
    // data which received by library....
}

如何使用库中的数据向应用程序引发事件

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提前感谢….

您应该更改开始方法的签名以传递给该代理：

public void start(string IP, int port, Action<string> callback)
{
    // start logic...

    // receives data from socket... send this data to user
    callback(data);
}

Library. Class a = new Library. Class();
a.start(ip, port, receivedData);

// I need this method called by library automatically when it receives data...

void receivedData(string data)
{
    // data which received by library....
}

public void start（字符串IP、int端口、操作回调）
{
//启动逻辑。。。
//从套接字接收数据…将此数据发送给用户
回调（数据）；
}
图书馆。a类=新图书馆。类（）；
a、 启动（ip、端口、接收数据）；
//我需要库在接收数据时自动调用此方法。。。
无效接收数据（字符串数据）
{
//图书馆收到的数据。。。。
}

将事件添加到库中，如下所示：

public event Action<string> OnDataReceived = null;

就这样

但您可能希望使用约定来编写事件，我建议您开始使用它，因为.NET正以这种方式使用事件，所以每当您遇到该约定时，您就会知道它是事件。 因此，如果我稍微重构一下您的代码，应该是这样的：

在类库中：

//...
public class YourEventArgs : EventArgs
{
   public string Data { get; set; }
}
//...

public event EventHandler DataReceived = null;
...
protected override OnDataReceived(object sender, YourEventArgs e)
{
   if(DataReceived != null)
   {
      DataReceived(this, new YourEventArgs { Data = "data to pass" });
   }
}

当您的类库想要启动事件时，它应该调用OnDataReceived，它负责检查是否有人在侦听，并构造适当的EventArgs，以便将数据传递给侦听器

在应用程序中，您应该更改方法签名：

Library.Class a = new Library.Class();
a.DataReceived += ReceivedData;
a.start(ip, port);

//...

void ReceivedData(object sender, YourEventArgs e)
{
  string data = e.Data;
  //...
}

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将事件添加到类中

public event DataReceivedEventHandler DataReceived;
public delegate void DataReceivedEventHandler(object sender, SocketDataReceivedEventArgs e);

在此处创建一个包含所需参数的类，例如Ex:

SocketDataReceivedEventArgs

触发事件类

SocketDataReceivedEventArgs DataReceiveDetails = new SocketDataReceivedEventArgs();
DataReceiveDetails.data = "your data here";
DataReceived(this, DataReceiveDetails);

应用程序中的创建方法

void receivedData(object sender, SocketDataReceivedEventArgs e)
{
    // e.data is data which received by library....
}

现在将处理程序附加到它

 Library. Class a = new Library. Class();
    a.DataReceived += receivedData;
    a.start(ip, port);

根据需要，您需要在多个线程中编写它 下面是您如何向上面添加线程安全支持的方法

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+1 for“.NET正以这种方式使用事件”，并提及

操作

回答。使用委托与仅使用事件有什么不同？