public TradingViewModel(ViewModelContext viewModelContext,
AccountViewModel accountViewModel, SymbolsViewModel symbolsViewModel,
TradeViewModel tradeViewModel, OrdersViewModel ordersViewModel,
IWpfExchangeService exchangeService, IAccountsService accountsService)
: base(viewModelContext)
{
AccountViewModel = accountViewModel;
SymbolsViewModel = symbolsViewModel;
TradeViewModel = tradeViewModel;
OrdersViewModel = ordersViewModel;
Symbols = new ObservableCollection <SymbolViewModel>();
this.exchangeService = exchangeService;
this.accountsService = accountsService;
ObserveSymbols();
ObserveAccount();
ObserveTrade();
ObserveOrders();
CloseCommand = new ViewModelCommand(Close);
}