MonoGame.Samples/NetworkStateManagement/Core/Networking/JoinSessionScreen.cs

//-----------------------------------------------------------------------------
// JoinSessionScreen.cs
//
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------

using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.GamerServices;


namespace NetworkStateManagement
{
	/// <summary>
	/// This menu screen displays a list of available network sessions,
	/// and lets the user choose which one to join.
	/// </summary>
	class JoinSessionScreen : MenuScreen
	{

		const int MaxSearchResults = 8;
		AvailableNetworkSessionCollection availableSessions;




		/// <summary>
		/// Constructs a menu screen listing the available network sessions.
		/// </summary>
		public JoinSessionScreen(AvailableNetworkSessionCollection availableSessions)
		: base(Resources.JoinSession)
		{
			this.availableSessions = availableSessions;

			foreach (AvailableNetworkSession availableSession in availableSessions)
			{
				// Create menu entries for each available session.
				MenuEntry menuEntry = new AvailableSessionMenuEntry(availableSession);
				menuEntry.Selected += AvailableSessionMenuEntrySelected;
				MenuEntries.Add(menuEntry);

				// Matchmaking can return up to 25 available sessions at a time, but
				// we don't have room to fit that many on the screen. In a perfect
				// world we should make the menu scroll if there are too many, but it
				// is easier to just not bother displaying more than we have room for.
				if (MenuEntries.Count >= MaxSearchResults)
					break;
			}

			// Add the Back menu entry.
			MenuEntry backMenuEntry = new MenuEntry(Resources.Back);
			backMenuEntry.Selected += BackMenuEntrySelected;
			MenuEntries.Add(backMenuEntry);
		}





		/// <summary>
		/// Event handler for when an available session menu entry is selected.
		/// </summary>
		void AvailableSessionMenuEntrySelected(object sender, PlayerIndexEventArgs e)
		{
			// Which menu entry was selected?
			AvailableSessionMenuEntry menuEntry = (AvailableSessionMenuEntry)sender;
			AvailableNetworkSession availableSession = menuEntry.AvailableSession;

			try
			{
				// Begin an asynchronous join network session operation.
				var networkSession = NetworkSession.JoinAsync(availableSession);

				// Activate the network busy screen, which will display
				// an animation until this operation has completed.
				NetworkBusyScreen busyScreen = new NetworkBusyScreen(networkSession);

				busyScreen.OperationCompleted += JoinSessionOperationCompleted;

				ScreenManager.AddScreen(busyScreen, ControllingPlayer);
			}
			catch (Exception exception)
			{
				NetworkErrorScreen errorScreen = new NetworkErrorScreen(exception);

				ScreenManager.AddScreen(errorScreen, ControllingPlayer);
			}
		}


		/// <summary>
		/// Event handler for when the asynchronous join network session
		/// operation has completed.
		/// </summary>
		void JoinSessionOperationCompleted(object sender, OperationCompletedEventArgs e)
		{
			try
			{
				// Use the result directly from the event args.
				NetworkSession networkSession = e.Result as NetworkSession;
				if (networkSession == null)
					throw new InvalidOperationException("NetworkSession result was null or invalid.");

				// Create a component that will manage the session we just joined.
				NetworkSessionComponent.Create(ScreenManager, networkSession);

				// Go to the lobby screen. We pass null as the controlling player,
				// because the lobby screen accepts input from all local players
				// who are in the session, not just a single controlling player.
				ScreenManager.AddScreen(new LobbyScreen(networkSession), null);

				availableSessions.Dispose();
			}
			catch (Exception exception)
			{
				NetworkErrorScreen errorScreen = new NetworkErrorScreen(exception);

				ScreenManager.AddScreen(errorScreen, ControllingPlayer);
			}
		}


		/// <summary>
		/// Event handler for when the Back menu entry is selected.
		/// </summary>
		void BackMenuEntrySelected(object sender, PlayerIndexEventArgs e)
		{
			availableSessions.Dispose();

			ExitScreen();
		}
	}
}