C# Invoke方法與WebSocket事件驅(qū)動的整合

在C#中，Invoke方法通常用于在UI線程上執(zhí)行代碼。WebSocket是一種網(wǎng)絡(luò)通信協(xié)議，允許在客戶端和服務(wù)器之間進行全雙工通信。事件驅(qū)動編程是一種編程范式，其中程序的組件通過響應(yīng)事件來通信。

將C#的Invoke方法與WebSocket事件驅(qū)動的整合，通常意味著在WebSocket客戶端接收到消息時，使用Invoke方法在UI線程上處理這些消息。以下是一個簡單的示例，展示了如何在C#中使用Invoke方法與WebSocket事件驅(qū)動的整合：

1. 首先，確保已經(jīng)安裝了System.Net.WebSockets包，以便使用WebSocket功能。

dotnet add package System.Net.WebSockets

2. 創(chuàng)建一個簡單的WebSocket客戶端類，該類使用System.Net.WebSockets命名空間中的類來處理WebSocket連接和消息。

using System;
using System.Net.WebSockets;
using System.Text;
using System.Threading.Tasks;

public class WebSocketClient
{
    private readonly ClientWebSocket _webSocket;
    private readonly Action<string> _messageHandler;

    public WebSocketClient(Uri serverUri, Action<string> messageHandler)
    {
        _webSocket = new ClientWebSocket();
        _messageHandler = messageHandler;
    }

    public async Task ConnectAsync()
    {
        await _webSocket.ConnectAsync(serverUri, CancellationToken.None);
    }

    public async Task CloseAsync()
    {
        await _webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closed", CancellationToken.None);
    }

    public async Task SendAsync(string message)
    {
        byte[] buffer = Encoding.UTF8.GetBytes(message);
        await _webSocket.SendAsync(new ArraySegment<byte>(buffer), WebSocketMessageType.Text, true, CancellationToken.None);
    }

    public event EventHandler<string> MessageReceived;

    private async Task OnMessageReceivedAsync(string message)
    {
        if (_messageHandler != null)
        {
            await WindowsFormsApplication1.InvokeAsync(() => _messageHandler(message));
        }
        MessageReceived?.Invoke(this, message);
    }

    public async Task StartListeningAsync()
    {
        _webSocket.MessageReceived += OnMessageReceivedAsync;
        while (true)
        {
            byte[] buffer = new byte[1024 * 4];
            WebSocketReceiveResult result = await _webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
            if (result.CloseStatus != WebSocketCloseStatus.NormalClosure)
            {
                break;
            }
            string message = Encoding.UTF8.GetString(buffer, 0, result.Count);
            await OnMessageReceivedAsync(message);
        }
    }
}

在這個示例中，WebSocketClient類包含一個MessageReceived事件，當(dāng)從WebSocket服務(wù)器接收到消息時，會觸發(fā)此事件。OnMessageReceivedAsync方法使用InvokeAsync方法將消息處理委托給UI線程。

3. 在Windows Forms應(yīng)用程序中使用WebSocketClient類。

using System;
using System.Net.WebSockets;
using System.Windows.Forms;

public class MainForm : Form
{
    private readonly WebSocketClient _webSocketClient;

    public MainForm()
    {
        _webSocketClient = new WebSocketClient(new Uri("ws://example.com"), OnMessageReceived);
        _webSocketClient.MessageReceived += OnMessageReceived;
    }

    private async void MainForm_Load(object sender, EventArgs e)
    {
        await _webSocketClient.ConnectAsync();
        await _webSocketClient.StartListeningAsync();
    }

    private async void OnMessageReceived(object sender, string message)
    {
        MessageBox.Show($"Received message: {message}");
    }

    protected override void OnFormClosing(FormClosingEventArgs e)
    {
        await _webSocketClient.CloseAsync();
        base.OnFormClosing(e);
    }
}

在這個示例中，MainForm類包含一個_webSocketClient實例，它連接到WebSocket服務(wù)器并啟動消息監(jiān)聽。OnMessageReceived方法將在接收到消息時顯示一個消息框。

這樣，我們就將C#的Invoke方法與WebSocket事件驅(qū)動的整合在一起，當(dāng)WebSocket客戶端接收到消息時，使用Invoke方法在UI線程上處理這些消息。