public CashFlowViewModel() { _contoData = new ContoData(); AddWithdrawCommand = new RelayCommand(AddWithdrawCommand_Executed); AddCostCommand = new RelayCommand(AddCostCommand_Executed); WithdrawDate = DateTime.Now; CostDate = DateTime.Now; SelfInvoices = new CollectionView(_contoData.CashFlowSelfInvoices()); Balance = _contoData.CashFlowBalance(); }