从 C# 中的类更新 GUI 的正确方法

Question

我正在寻找一种方法来从我想要独立而不依赖于 GUI 的类中更新 GUI。它是一个由监听器和客户端组成的网络类。这个类可以连接然后发送/接收数据。我希望这些数据能够使用 GUI 显示，但在类本身中没有任何与 GUI 相关的代码。

所以简而言之，网络类只知道自己。 GUI 知道网络类。

这是我要添加代码的地方

    public void ReceiveBytes()
    {
        byte[] receivedPacket;

        while (IsListeningForBytes)
        {
            receivedPacket = new byte[Packet.BUFFERSIZE];

            try
            {
                int bytesRead = ClientSocket.Receive(receivedPacket, SocketFlags.None);

                if (bytesRead > 0)
                {
                    SocketObject.ProcessMessage(receivedPacket);
                    // Update GUI here after the message has been processed.
                }
                else
                {
                    throw new Exception("No bytes read");
                }
            }
            catch (Exception ex)
            {
                IsListeningForBytes = false;
                Disconnect();
                Console.WriteLine(ex.Message);
            }
        }
    }

编辑：对不起大家，我会尽量让事情更清楚。我正在使用 Windows 窗体，为了这个练习，我们会说我有三个不同的控件：一个列表框、一个组合框和一个文本框，它们将根据发送的内容获取数据。 （我的实际应用程序有需要更新的列表框、组合框、复选框等）。

我知道我不应该从我的对象中引用 GUI，因此我的问题。

至于相关代码，不知道你想看什么。

我已阅读有关事件处理程序和委托的信息，但我不确定在这种情况下如何实际实现它。我最初将 GUI 更新方法作为操作传递给在需要时调用的类，但这似乎很冗长，并没有专门更新我想要的控件。

感谢您迄今为止的帮助。

Answer 1

直接从您的对象更新您的 UI 将违反 OOP。

相反，实现一个事件让调用者/用户知道发生了什么事，并让他们负责更新 UI。

这是一个例子：

//added event, SomeDataObject is for you to create.
public event EventHandler<SomeDataObject> MessageProcessed;
public void ReceiveBytes()
{
    byte[] receivedPacket;

    while (IsListeningForBytes)
    {
        receivedPacket = new byte[Packet.BUFFERSIZE];

        try
        {
            int bytesRead = ClientSocket.Receive(receivedPacket, SocketFlags.None);

            if (bytesRead > 0)
            {
                SocketObject.ProcessMessage(receivedPacket);
                // no UI update but fire an event
                MessageProcessed?.Invoke(this, new SomeDataObject());
            }
            else
            {
                throw new Exception("No bytes read");
            }
        }
        catch (Exception ex)
        {
            IsListeningForBytes = false;
            Disconnect();
            Console.WriteLine(ex.Message);
        }
    }
}

见：

Understanding events and event handlers in C#

或

https://msdn.microsoft.com/en-us/library/db0etb8x(v=vs.110).aspx

或

https://duckduckgo.com/?q=EventHandler+C%23&t=h_&ia=qa

更新

---

那么，它是如何工作的：

在你的 FooGUI 类中，你需要订阅事件。

//so, your UI, can be a window, a form or ... console.
//I'll call your class BytesReceiver
public class FooGUI
{
     BytesReceiver _receiver = new BytesReceiver();

     //somewhere, in some function your listener has started
     void Init()
     {
         //we added an event earlier, now attach a handler.
         //a handler is a function, bound to some signature (as defined by the delegate)
         //which will be executed when the event is triggered.

          //so again; we bind a function to the event, which is invoked when the event is 
          //raised.

          //keep in mind: the Invoke take place on the other thread; so the handler
          //runs on that same thread.

          //there is no magical polling taking place: it's just a 
          //function call (from receiver).

         //note: there are various ways to bind a function: I'll use lambda here
         _receiver.MessageProcessed += (sender,e) =>
         {
             //update GUI here. 
         }

         //since there your while loop waits for a long time
         //there must be some non-blocking operation, presumably on another thread.
         _receiver.StartListening();
     }
}