从 Controller .Net Core 2.1 调用 Signalr 方法

Question

我正在尝试从（ASP.NET 核心）MVC 控制器调用信号器集线器 class 中的方法，但我无法在网上找到说明如何调用的示例。

注意：有很多将旧版本的信号器与 .Net Framework 结合使用的示例，但是 none 我可以看到它展示了如何在 .Net Core 中执行此操作。

我需要将来自 MVC 操作结果的 ID 直接传递到我的 Hub，而不是将 ID 传递到页面，然后必须将客户端连接返回到 Hub。

public class ChatHub : Hub
{ 
    public async Task DoSomething(int id)
    {            
        //// Something in here.
    }
}



public class HomeController : Controller
{
    private readonly IHubContext<ChatHub> _hubContext;

    public HomeController(IHubContext<ChatHub> hubContext)
    {
        _hubContext = hubContext;
    }

    public async Task<ActionResult> Index(int id) 
    {

         //// Call the DoSomething method from here, passing the id across.
         await _hubContext.Clients.All.SendAsync("AddToGroup", groupId);
    }
}

请问有办法吗？（还是我看错了，有没有更好的方法可以达到同样的效果？）

更新： 如果我将 Id 传递到视图中，然后使用 JavaScript 调用集线器，这将调用 DoSomething 方法，所以我可以看到它们都正确地挂在一起，但当我尝试在 C# 中调用它时却没有。

Answer 1

您可以使用 IHubContext 来执行此操作：

public class HomeController : Controller
{
    private readonly IHubContext<ChatHub> _hubContext;

    public HomeController(IHubContext<ChatHub> hubContext)
    {
        _hubContext = hubContext;
    }

    public async Task<ActionResult> Index(int id) 
    {
         //// Call the DoSomething method from here, passing the id across.
         await _hubContext.Clients.All.SendAsync("DoSomething", id);
    }
}

Full docs and examples here.

Answer 2

我认为您误解了它们是如何协同工作的（这与我昨天所做的相同），集线器代码用于客户端脚本代码回调然后执行操作，而IHubContext 用作将发送到客户端的强类型方法

枢纽

// This class is used by the JavaScript Client to call into the .net core application.
public class ChatHub : Hub<IChatClient>
{

    public static ConcurrentDictionary<string, string> Connections = new ConcurrentDictionary<string, string>();

    // As an example, On connection save the user name with a link to the client Id for later user callback
    public override Task OnConnectedAsync()
    {
        var user = Context.User.Identity.Name;

        Connections.AddOrUpdate(this.Context.ConnectionId, user, (key, oldValue) => user);

        return base.OnConnectedAsync();
    }

    public override Task OnDisconnectedAsync(Exception exception)
    {
        // Do something on disconnect.
    }

    // Add other methods you want to be able to call from JavaScript side in here...
    public void SendMessage(int id, string message)
    {
        // Message doing stuff here.
    }
}

聊天客户端界面

// This provides strongly-typed methods that you'll have on the Client side but these don't exist on the server.
public interface IChatClient
{
    //So this method is a JS one not a .net one and will be called on the client(s)
    Task DoSomething(int id);

    Task NotificationUpdate(int id, string message);
}

控制器

public class HomeController : Controller
{
    private readonly IHubContext<ChatHub, IChatClient> _hubContext;

    public HomeController(IHubContext<ChatHub, IChatClient> hubContext)
    {
        _hubContext = hubContext;
    }

    public async Task<ActionResult> Index(int id) 
    {

         // This calls the method on the Client-side
         await _hubContext.Clients.All.DoSomething(id);
    }
}

从 Controller .Net Core 2.1 调用 Signalr 方法

Call Signalr method from Controller .Net Core 2.1

c#

asp.net-core-mvc

signalr

signalr-hub

asp.net-core-signalr