asp.net-mvc-4 - 检查SignalR组是否为空？

Question

在OnConnected方法中，客户端被添加到带有他的名字的组中(组包含所有客户端ID)，然后他的名字被添加到列表中(如果不存在)。

static List<string> onlineClients = new List<string>(); // list of clients names

public override Task OnConnected()
{
    Groups.Add(Context.ConnectionId, Context.User.Identity.Name);

    if (!onlineClients.Exists(x => x == Context.User.Identity.Name))
    {
        onlineClients.Add(Context.User.Identity.Name);
    }

    return base.OnConnected();
}

在 OnDisconnected 方法中，我试图测试该组是否为空以从列表中删除元素。但删除最后一个连接后，该组不为空。

public override Task OnDisconnected(bool stopCalled)
{
    if (stopCalled)
    {
        // We know that Stop() was called on the client,
        // and the connection shut down gracefully.

        Groups.Remove(Context.ConnectionId, Context.User.Identity.Name);

        if (Clients.Group(Context.User.Identity.Name) == null)
        {
            onlineClients.Remove(Context.User.Identity.Name);
        }

    }
    return base.OnDisconnected(stopCalled);
}

我可以检查空组吗？

Answer 1

我认为这对你的问题的答复有点晚了，也许你已经忘记了:d

我使用包含组名称(User.Identity.Name)及其客户编号的字典解决了我的问题，如下所示。

private static Dictionary<string, int> onlineClientCounts  = new Dictionary<string, int>();

public override Task OnConnected()
{
    var IdentityName = Context.User.Identity.Name;
    Groups.Add(Context.ConnectionId, IdentityName);

    int count = 0;
    if (onlineClientCounts.TryGetValue(IdentityName, out count))
        onlineClientCounts[IdentityName] = count + 1;//increment client number
    else
        onlineClientCounts.Add(IdentityName, 1);// add group and set its client number to 1

    return base.OnConnected();  
}

public override Task OnDisconnected(bool stopCalled)
{
    var IdentityName = Context.User.Identity.Name;
    Groups.Remove(Context.ConnectionId, IdentityName);

    int count = 0;
    if (onlineClientCounts.TryGetValue(IdentityName, out count))
    {
        if (count == 1)//if group contains only 1client
            onlineClientCounts.Remove(IdentityName);
        else
            onlineClientCounts[IdentityName] = count - 1;
    }

    return base.OnDisconnected(stopCalled);
}