如何解决“öbject引用未设置为对象的实例”

Question

如何解决“öbject引用未设置为对象的实例”？

  private readonly IIntegrationEventLogService _eventLogService;
        private readonly orderdbContext orderdbContext;
        private readonly IEventBus _eventBus;
        private readonly IOrderIntegrationEventService 
  _orderIntegrationEventService;
        private OrderIntegrationEventService orderIntegrationEventService;
        private readonly Func<DbConnection, IIntegrationEventLogService> 
  _integrationEventLogServiceFactory;
        private readonly OrderSettings _settings;
        private int personaId = 0, orderId = 0, cartId = 0, productId = 0, 
        companyBranchId = 0, optionalResult;
        ResponseDetails responseDetails = null;
        public IGrocerOrders _grocerOrder; 

    var priceChangedEvent = new OrderStartedDomainEvent(check);

awaitorderIntegrationEventService. SaveEventAndorderContextChangesAsync(priceChangedEvent);
await 
orderIntegrationEventService.PublishThroughEventBusAsync(priceChangedEvent);
var priceChangedEvent = new OrderStartedDomainEvent(data);    

 _catalogIntegrationEventService.
  SaveEventAndCatalogContextChangesAsync(priceChan 
  gedEvent);
  await _grocerOrder.PublishThroughEventBusAsync(priceChangedEvent);
            return Ok(await _grocerOrder.GenerateOrder(data)); 

Plaese帮助我解决“öbject引用未设置为对象实例”的问题