此clationt是处置信号的

Question

在用户连接时，一切进展顺利。当我有一个产品更新（可供出售）时，onproductStartsales事件被调用。 但是存在一个问题，因为介绍了集线器中的客户端列表，因此消息不会出现在客户端。 这是我的中心的代码。

public class SalesHub : Hub
{
    private readonly ProductDatabaseListener _listener;

    public SalesHub(ProductDatabaseListener listener)
    {
        _listener = listener ?? throw new ArgumentNullException(nameof(listener));
        _listener.OnProductStartSales += (s, p) => ProductStartSales(p);
        _listener.OnProductDataChanged += (s, p) => ProductDataChanged(p);
    }

    public async Task ListenProduct(string productId)
    {
        await this.Groups.AddToGroupAsync(Context.ConnectionId, productId);
    }

    private async Task ProductStartSales(Product product)
    {
        await this.Clients.Group(product.Id).SendAsync("StartSales", product.Id);
        // await this.Clients.All.SendAsync("StartSales", product.Id);
    }

    private async Task ProductDataChanged(Product product)
    {
        await this.Clients.Group(product.Id).SendAsync("DataChanged", product);
    }
}

这是听众的守则。

public class ProductDatabaseListener
{
    private readonly IRepository<Product> _repository;
    private readonly object _locker = new object();

    public ProductDatabaseListener(IServiceProvider serviceProvider)
    {
        using (var scope = serviceProvider.CreateScope())
        {
            _repository = scope.ServiceProvider.GetRequiredService<IRepository<Product>>() ?? throw new ArgumentNullException(nameof(_repository));
        }
    }

    public event EventHandler<Product> OnProductStartSales;
    public event EventHandler<Product> OnProductDataChanged;

    // Need better performance...
    public async Task ListenMongo()
    {
        while (true)
        {
            var products = await _repository.GetRange(0, int.MaxValue);
            var date = DateTime.Now;
            List<Task> tasks = new List<Task>();

            foreach (var product in products)
            {
                if (product.IsSalesStart)
                {
                    continue;
                }

                if (product.StartOfSales <= date)
                {
                    product.IsSalesStart = true;
                    OnProductStartSales?.Invoke(this, product);
                    tasks.Add(_repository.Update(product));
                }
            }

            Task.WaitAll(tasks.ToArray());

            await Task.Delay(1000);
        }
    }
}

这是客户端代码

"use strict";

var connection = new signalR.HubConnectionBuilder().withUrl("/salesHub").build();

connection.on("ReceiveMessage", function (id) {
    var li = document.createElement("li")
    document.getElementById("fromHub").appendChild(li)
    li.textContent = id;
});

connection.on("startSales", function (id) {
    var productId = document.getElementById("objectId").getAttribute("value");
    if (productId == id) {
        var button = document.getElementById("buy")
        button.hidden = false
    }
});

connection.logging = true;

connection.start().then(function () {
    var productId = document.getElementById("objectId").getAttribute("value");
    connection.invoke("ListenProduct", productId).catch(function (err) {
        return console.error(err.toString());
    });
    event.preventDefault();
}).catch(function (err) {
    return console.error(err.toString());
});