SignalR Hub OnDisconnectedAsync 方法在 Blazor 服务器中未命中

Question

在这里，我试图在我的集线器的 OnDisconnectedAsync 方法中从已连接的 connectedId 列表 UserHandler.ConnectedUser 中删除 ConnectionId。
但问题是，当用户从应用程序注销或关闭 window 时，集线器上的 OnDisconnectedAsync 方法不会被命中。

如果对我的代码有任何帮助，我们将不胜感激。谢谢你。

下面是我的hub

public class ChatHub : Hub
{
    public List<string> SendingUserList = new List<string>();
    public async Task SendMessage(string to, string message)
    {
        var senderConnectionId = Context.ConnectionId;
        SendingUserList.Add(to);
        SendingUserList.Add(senderConnectionId);
        foreach (var connectionId in SendingUserList)
        {
            await Clients.Client(connectionId).SendAsync("ReceiveMessage", message);
        }
    }
    public override Task OnConnectedAsync()
    {
        Clients.All.SendAsync("ReciveUser", UserHandler.UserName, Context.ConnectionId);
        return base.OnConnectedAsync();
    }
    public override async Task OnDisconnectedAsync(Exception e)
    {
        UserHandler.ConnectedUser.Remove(Context.ConnectionId));
        await base.OnDisconnectedAsync(e);
    }      
}
public static class UserHandler
{
    public static HashSet<string> ConnectedUser = new HashSet<string>();
    public static string UserName { get; set; }
}

下面是我剩下的代码

    protected override async Task OnInitializedAsync()
    {
        UserHandler.UserName = httpContextAccessor.HttpContext.User.Identity.Name;
        hubConnection = new HubConnectionBuilder()
            .WithUrl(NavigationManager.ToAbsoluteUri("/chathub"))
            .Build();
        hubConnection.ServerTimeout = TimeSpan.FromMinutes(60);
        hubConnection.On<string>("ReceiveMessage", BroadcastMessage);
        hubConnection.On<string,string>("ReciveUser", RefreshUserList);

        await hubConnection.StartAsync();

        StateHasChanged();
    }
    private void RefreshUserList(string connectedUserId, string connectionId )
    {
        UserHandler.ConnectedUser.Add(connectionId);
        connectedUserList = UserHandler.ConnectedUser;
        StateHasChanged();
    }
    private void BroadcastMessage(string message)
    {
        var encodedMsg = $"{message}";
        messages.Add(encodedMsg);
        StateHasChanged();
    }
    public async ValueTask DisposeAsync()
    {
        await hubConnection.DisposeAsync();
    }

Answer 1

您需要在 Hub 的使用者（Razor 组件）中实现 IAsyncDisposable 接口，如下所示：

@implements IAsyncDisposable

添加这些方法：

public void Dispose()
    {
       
        hubConnection.DisposeAsync();
    }

    public async ValueTask DisposeAsync()
    {
        await hubConnection.DisposeAsync();
    }

现在，当您关闭客户端页面时，将调用 OnDisconnectedAsync 方法。

SignalR Hub OnDisconnectedAsync 方法在 Blazor 服务器中未命中

SignalR Hub OnDisconnectedAsync Method Does Not Get Hit in Blazor Server

c#

signalr

asp.net-core

blazor