Microsoft SignalR自托管示例报错求助：复制代码运行异常

Hey there, let's troubleshoot your SignalR self-hosting demo issue. First thing I notice—your Startup.Configuration method is cut off (app.Us...)—that's almost certainly contributing to the error you're seeing. Let's walk through the fixes step by step.

1. Complete the Startup Class Configuration #

Your Startup class needs to properly enable CORS (critical for cross-origin connections) and map SignalR's routes. Here's the full, corrected code including a sample hub to test with:

using System;
using Microsoft.AspNet.SignalR;
using Microsoft.Owin.Hosting;
using Owin;
using Microsoft.Owin.Cors;

namespace SignalRSelfHost
{
    class Program
    {
        static void Main(string[] args)
        {
            string url = "http://localhost:8080";
            using (WebApp.Start(url))
            {
                Console.WriteLine("Server running on {0}", url);
                Console.ReadLine();
            }
        }
    }

    class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            // Enable CORS first - this MUST come before SignalR mapping
            app.UseCors(CorsOptions.AllowAll);
            
            // Map SignalR to its default route (/signalr)
            app.MapSignalR();
        }
    }

    // Add a sample hub to validate functionality
    public class ChatHub : Hub
    {
        public void SendMessage(string name, string message)
        {
            // Broadcast message to all connected clients
            Clients.All.receiveMessage(name, message);
        }
    }
}

2. Ensure Required NuGet Packages Are Installed #

Most runtime errors here come from missing dependencies. Install these via the Package Manager Console:

Install-Package Microsoft.AspNet.SignalR.SelfHost
Install-Package Microsoft.Owin.Cors
Install-Package Microsoft.Owin.Hosting

3. Fix Common Error Scenarios #

• Port Conflict: If you get a "port already in use" error, switch to a different port (e.g., http://localhost:8081) or run netstat -ano | findstr :8080 in Command Prompt to locate and terminate the process using the port.
• Cross-Origin Issues: If your frontend can't connect, double-check that app.UseCors(CorsOptions.AllowAll) runs before app.MapSignalR()—order matters here.
• Namespace Mix-Up: Make sure you're using Microsoft.AspNet.SignalR (not Microsoft.AspNetCore.SignalR)—this is the full .NET Framework version of SignalR, not the Core variant.

4. Validate the Server #

Once you've made these changes, start the server. To confirm SignalR is working, navigate to http://localhost:8080/signalr/hubs in your browser. You should see auto-generated JavaScript proxy code—this means the server is configured correctly.

内容的提问来源于stack exchange，提问作者FirstByte