[C#] Hướng dẫn demo ứng dụng chat sử dụng công nghệ SignaIR

PM> Install-Package Microsoft.AspNet.SignalR -Version 2.4.0

using Microsoft.AspNet.SignalR;
using Microsoft.Owin.Cors;
using Microsoft.Owin.Hosting;
using Owin;
using System;
using System.Reflection;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace SignalRChat
{

    public partial class WinFormsServer : Form
    {
        private IDisposable SignalR { get; set; }
        const string ServerURI = "http://localhost:8080";

        internal WinFormsServer()
        {
            InitializeComponent();
        }

        private void ButtonStart_Click(object sender, EventArgs e)
        {
            WriteToConsole("Starting server...");
            ButtonStart.Enabled = false;
            Task.Run(() => StartServer());
        }

        private void ButtonStop_Click(object sender, EventArgs e)
        {
            //SignalR will be disposed in the FormClosing event
            Close();
        }

        private void StartServer()
        {
            try
            {
                SignalR = WebApp.Start(ServerURI);
            }
            catch (TargetInvocationException)
            {
                WriteToConsole("Server failed to start. A server is already running on " + ServerURI);
               
                this.Invoke((Action)(() => ButtonStart.Enabled = true));
                return;
            }
            this.Invoke((Action)(() => ButtonStop.Enabled = true));
            WriteToConsole("Server started at " + ServerURI);
        }
     
        internal void WriteToConsole(String message)
        {
            if (RichTextBoxConsole.InvokeRequired)
            {
                this.Invoke((Action)(() =>
                    WriteToConsole(message)
                ));
                return;
            }
            RichTextBoxConsole.AppendText(message + Environment.NewLine);
        }

        private void WinFormsServer_FormClosing(object sender, FormClosingEventArgs e)
        {
            
            if (SignalR != null)
            {
                SignalR.Dispose();
            }
        }
    }
    
    class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            app.UseCors(CorsOptions.AllowAll);
            app.MapSignalR();
        }
    }
   
    public class MyHub : Hub
    {
        public void Send(string name, string message)
        {
            Clients.All.addMessage(name, message);
        }
        public override Task OnConnected()
        {
            Program.MainForm.WriteToConsole("Client connected: " + Context.ConnectionId);
            return base.OnConnected();
        }
        public override Task OnDisconnected()
        {
            Program.MainForm.WriteToConsole("Client disconnected: " + Context.ConnectionId);
            return base.OnDisconnected();
        }
    }
}

using Microsoft.AspNet.SignalR.Client;
using System;
using System.Net.Http;
using System.Windows.Forms;

namespace WinFormsClient
{
    public partial class WinFormsClient : Form
    {       
        private String UserName { get; set; }
        private IHubProxy HubProxy { get; set; }
        const string ServerURI = "http://localhost:8080/signalr";
        private HubConnection Connection { get; set; }
        
        internal WinFormsClient()
        {
            InitializeComponent();
        }

        private void ButtonSend_Click(object sender, EventArgs e)
        {
            HubProxy.Invoke("Send", UserName, TextBoxMessage.Text);
            TextBoxMessage.Text = String.Empty;
            TextBoxMessage.Focus();
        }

       
        private async void ConnectAsync()
        {
            Connection = new HubConnection(ServerURI);
            Connection.Closed += Connection_Closed;
            HubProxy = Connection.CreateHubProxy("MyHub");
          
            HubProxy.On<string, string>("AddMessage", (name, message) =>
                this.Invoke((Action)(() =>
                    RichTextBoxConsole.AppendText(String.Format("{0}: {1}" + Environment.NewLine, name, message))
                ))
            );
            try
            {
                await Connection.Start();
            }
            catch (HttpRequestException)
            {
                StatusText.Text = "Unable to connect to server: Start server before connecting clients.";               
                return;
            }

            //Activate UI
            SignInPanel.Visible = false;
            ChatPanel.Visible = true;
            ButtonSend.Enabled = true;
            TextBoxMessage.Focus();
            RichTextBoxConsole.AppendText("Connected to server at " + ServerURI + Environment.NewLine);
        }

       
        private void Connection_Closed()
        {
            //Deactivate chat UI; show login UI. 
            this.Invoke((Action)(() => ChatPanel.Visible = false));
            this.Invoke((Action)(() => ButtonSend.Enabled = false));
            this.Invoke((Action)(() => StatusText.Text = "You have been disconnected."));
            this.Invoke((Action)(() => SignInPanel.Visible = true));
        }

        private void SignInButton_Click(object sender, EventArgs e)
        {
            UserName = UserNameTextBox.Text;
           
            if (!String.IsNullOrEmpty(UserName))
            {
                StatusText.Visible = true;
                StatusText.Text = "Connecting to server...";
                ConnectAsync();
            }
        }

        private void WinFormsClient_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (Connection != null)
            {
                Connection.Stop();
                Connection.Dispose();
            }
        }
    }
}