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Data Grid

SignalR Service

This example demonstrates real-time data update in a DataGrid bound to a SignalR service. Access to the service is configured in a CustomStore.

The CustomStore fetches the remote dataset at launch and keeps its local copy. Whenever the remote dataset changes, the server calls a client-side function that updates the local copy of the dataset (updateStockPrices in this demo). This function uses the store's push(changes) method.

For server-side configuration, refer to the ASP.NET MVC version of this demo.

For more information about integration with push services, refer to the following help topic: Integration with Push Services.

NOTE: Data used in this demo is for demonstration purposes only.

using System.Collections.Generic; using DevExtreme.MVC.Demos.Models.SignalR; using Microsoft.AspNet.SignalR; namespace DevExtreme.MVC.Demos.Hubs { public class LiveUpdateSignalRHub : Hub { private readonly StockTicker _stockTicker; public LiveUpdateSignalRHub() { _stockTicker = StockTicker.Instance; } public IEnumerable<Stock> GetAllStocks() { return _stockTicker.GetAllStocks(); } } }
using System; namespace DevExtreme.MVC.Demos.Models.SignalR { public class Stock { readonly decimal _initPrice; public Stock(decimal price) { Price = price; DayMax = price; DayMin = price; _initPrice = Price; } public string Symbol { get; set; } public decimal Price { get; set; } public decimal DayMax { get; set; } public decimal DayMin { get; set; } public decimal DayOpen { get; set; } public DateTime LastUpdate { get; set; } public decimal Change { get { return Price - DayOpen; } } public double PercentChange { get { return (double)Math.Round(Change * 100 / DayOpen, 2); } } public void Update() { var isNewDay = LastUpdate.Day != DateTime.Now.Day; var change = GenerateChange(); var newPrice = _initPrice + _initPrice * change; Price = newPrice; LastUpdate = DateTime.Now; if(Price > DayMax || isNewDay) DayMax = Price; if(Price < DayMin || isNewDay) DayMin = Price; } static Random random = new Random(); decimal GenerateChange() { return (decimal)random.Next(-200, 200) / 10000; } } }
using System; using System.Collections.Generic; using System.Threading; using DevExtreme.MVC.Demos.Hubs; using Microsoft.AspNet.SignalR; using Microsoft.AspNet.SignalR.Hubs; namespace DevExtreme.MVC.Demos.Models.SignalR { public class StockTicker { public readonly static StockTicker Instance = new StockTicker(GlobalHost.ConnectionManager.GetHubContext<LiveUpdateSignalRHub>().Clients); private readonly IEnumerable<Stock> _stocks; private IHubConnectionContext<dynamic> Clients { get; set; } private readonly TimeSpan _updateInterval = TimeSpan.FromMilliseconds(500); private readonly Random _updateOrNotRandom = new Random(); private readonly Timer _timer; private readonly object _updateStockPricesLock = new object(); static readonly Random random = new Random(); private StockTicker(IHubConnectionContext<dynamic> clients) { Clients = clients; _stocks = GenerateStocks(); _timer = new Timer(UpdateStockPrices, null, _updateInterval, _updateInterval); } public IEnumerable<Stock> GetAllStocks() { return _stocks; } static IEnumerable<Stock> GenerateStocks() { return new[] { new Stock(37.95M) { Symbol = "MSFT", DayOpen=36.5M, LastUpdate = DateTime.Now }, new Stock(24.85M) { Symbol = "INTC", DayOpen=24.9M, LastUpdate = DateTime.Now }, new Stock(22.99M){ Symbol = "CSCO", DayOpen=22.7M, LastUpdate = DateTime.Now }, new Stock(30.71M){ Symbol = "SIRI", DayOpen=30.7M, LastUpdate = DateTime.Now }, new Stock(58.73M){ Symbol = "AAPL", DayOpen=54.9M, LastUpdate = DateTime.Now }, new Stock(110M){ Symbol = "HOKU", DayOpen=121.2M, LastUpdate = DateTime.Now }, new Stock(38.11M){ Symbol = "ORCL", DayOpen=37.9M, LastUpdate = DateTime.Now }, new Stock(17.61M) { Symbol = "AMAT", DayOpen=17.5M, LastUpdate = DateTime.Now }, new Stock(40.80M){ Symbol = "YHOO", DayOpen=39.9M, LastUpdate = DateTime.Now }, new Stock(31.85M){ Symbol = "LVLT", DayOpen=32.9M, LastUpdate = DateTime.Now }, new Stock(20.63M){ Symbol = "DELL", DayOpen=17.9M, LastUpdate = DateTime.Now }, new Stock(63.70M) { Symbol = "GOOG", DayOpen=55.9M, LastUpdate = DateTime.Now } }; } private void UpdateStockPrices(object state) { lock(_updateStockPricesLock) { foreach(var stock in _stocks) { if(TryUpdateStockPrice(stock)) { BroadcastStockPrice(stock); } } } } private bool TryUpdateStockPrice(Stock stock) { var r = _updateOrNotRandom.NextDouble(); if(r > .1) { return false; } stock.Update(); return true; } private void BroadcastStockPrice(Stock stock) { Clients.All.updateStockPrice(stock); } } }