https://codingblast.com/connect4-live-game-signalr-blazor/ ‎- SignalR Connect4 Blazor

Connect4Hub.cs

public class Connect4Hub: Hub {
	private readonly ILogger < Connect4Hub > _logger;
	public const string OnGameReady = "OnGameReady";
	public const string NotifySecondPlayer = "NotifySecondPlayer";
	public const string NotifyGameHost = "NotifyGameHost";
	public const string NotifyOnGameOver = "NotifyOnGameOver";
	public const string NotifyOnDraw = "NotifyOnDraw";
	public const string NotifyOnPlayerLeft = "NotifyOnPlayerLeft";
	private const string Connect4Group = "Connect4";

	public Connect4Hub(ILogger < Connect4Hub > logger) {
		_logger = logger;
	}

	public async Task JoinedQueue() {
		await Groups.AddToGroupAsync(Context.ConnectionId, Connect4Group);
	}

	public async Task GameReady(GameBoard board) {
		await Clients.Group(Connect4Group).SendAsync(OnGameReady, board);
	}

	public async Task OnPlayerDisconnected(Guid userId) {
		await Groups.RemoveFromGroupAsync(Context.ConnectionId, Connect4Group);
		_logger.LogWarning("User left");

		await Clients.Group(Connect4Group).SendAsync(NotifyOnPlayerLeft, userId);
	}

	public async Task OnOpponentMoveReceived(GameBoard board) {
		await Clients.Group(Connect4Group).SendAsync(NotifyGameHost, board);
	}

	public async Task OnHostMoveReceived(GameBoard board) {
		await Clients.Group(Connect4Group).SendAsync(NotifySecondPlayer, board);
	}

	public async Task OnGameOver(GameBoard board, WinningPlay winningPlay) {
		await Clients.Group(Connect4Group).SendAsync(NotifyOnGameOver, board, winningPlay);
	}

	public async Task OnDraw(GameBoard board) {
		await Clients.Group(Connect4Group).SendAsync(NotifyOnDraw, board);
	}
}