Wpf：在应用程序生命周期中使用单独的 dbcontext

Question

I have a wpf application with dependency injection. I registered my context as service to use in app like below.

serviceCollection.AddDbContext<Context>(p => p.UseSqlServer(configuration.GetConnectionString("DefaultConnection")));

I have another service that should fetch data from database every 15 seconds to check for new entities added and i do it with an event service and start the service in MainWindow.xaml startup and it goes to another thread.

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    Task newOrdersTask = _eventService.SubscribeToNewOrders();
}

But sometimes while working with appplication i get this error.

A second operation started on this context before a previous operation completed

How can i handle these scenarios?

Answer 1

It is a bad idea to have a singleton DbContext in your entire application, especially when working on different threads is being considered.

Passing ServiceLifetime.Transient as the second argument to AddDbContext will force creation of a new DbContext every time it gets injected by the container. However, by doing so, you are going to miss a lot of features EF Core DbContext provides by default. You may consider implementing something like " ambient context pattern " to somehow preserve these features.