CryptoExchange.Net/Examples/BlazorClient/Pages/OrderBooks.razor

@page "/OrderBooks"
@using Binance.Net.SymbolOrderBooks
@using Bitfinex.Net.SymbolOrderBooks
@using Bittrex.Net.SymbolOrderBooks
@using Bybit.Net.SymbolOrderBooks
@using CryptoExchange.Net.Interfaces
@using CryptoExchange.Net.Objects
@using CryptoExchange.Net.Sockets
@using CoinEx.Net.SymbolOrderBooks
@using FTX.Net.SymbolOrderBooks
@using Huobi.Net.SymbolOrderBooks
@using Kraken.Net.SymbolOrderBooks
@using Kucoin.Net.Clients
@using Kucoin.Net.SymbolOrderBooks
@using System.Collections.Concurrent
@using System.Timers
@implements IDisposable

<h3>ETH-BTC books, live updates:</h3>
@foreach(var book in _books.OrderBy(p => p.Key))
{
    <div style="margin-bottom: 20px;">
        <h4>@book.Key</h4>
        @if (book.Value.AskCount >= 3 && book.Value.BidCount >= 3)
        {
            for (var i = 0; i < 3; i++)
            {
                <div>@book.Value.Bids.ElementAt(i).Price - @book.Value.Asks.ElementAt(i).Price</div>
            }
        }
    </div>
}

@code{
    private Dictionary<string, ISymbolOrderBook> _books = new Dictionary<string, ISymbolOrderBook>();
    private Timer _timer;

    protected override async Task OnInitializedAsync()
    {
        // Since the Kucoin order book stream needs authentication we will need to provide API credentials beforehand
        KucoinClient.SetDefaultOptions(new Kucoin.Net.Objects.KucoinClientOptions
            {
                ApiCredentials = new Kucoin.Net.Objects.KucoinApiCredentials("KEY", "SECRET", "PASSPHRASE")
            });

        _books = new Dictionary<string, ISymbolOrderBook>
            {
                { "Binance", new BinanceSpotSymbolOrderBook("ETHBTC") },
                { "Bitfinex", new BitfinexSymbolOrderBook("tETHBTC") },
                { "Bittrex", new BittrexSymbolOrderBook("ETH-BTC") },
                { "Bybit", new BybitSpotSymbolOrderBook("ETHBTC") },
                { "CoinEx", new CoinExSpotSymbolOrderBook("ETHBTC") },
                { "FTX", new FTXSymbolOrderBook("ETH/BTC") },
                { "Huobi", new HuobiSpotSymbolOrderBook("ethbtc") },
                { "Kraken", new KrakenSpotSymbolOrderBook("ETH/XBT") },
                { "Kucoin", new KucoinSpotSymbolOrderBook("ETH-BTC") },
            };

        await Task.WhenAll(_books.Select(b => b.Value.StartAsync()));

        // Use a manual update timer so the page isn't refreshed too often
        _timer = new Timer(500);
        _timer.Start();
        _timer.Elapsed += (o, e) => InvokeAsync(StateHasChanged);
    }

    public void Dispose()
    {
        _timer.Stop();
        _timer.Dispose();
        foreach (var book in _books)
            // It's not necessary to wait for this
            _ = book.Value.StopAsync();
    }
}