My application: .Net6 and used MediatR to handle domain events. when I try to get the data from database, i get the following error:
Cannot access a disposed context instance. A common cause of this error is disposing a context instance that was resolved from dependency injection and then later trying to use the same context instance elsewhere in your application. This m ay occur if you are calling 'Dispose' on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the dependency injection container take care of disposing context instances. Object name: 'ApplicationDbContext'.
I override savechanges as follow:
public class DomainEventPublishingInterceptor:SaveChangesInterceptor
{
private readonly IMediator _mediator;
public DomainEventPublishingInterceptor(IMediator mediator)
{
_mediator = mediator;
}
public override ValueTask<int> SavedChangesAsync(SaveChangesCompletedEventData eventData, int result, CancellationToken cancellationToken = new())
{
foreach (var entityEntry in eventData.Context.ChangeTracker.Entries<IAggregateRoot>()) PublishEvents(entityEntry.Entity);
return new ValueTask<int>(result);
}
...
...
In program.cs I inject MediatR using AddMediator extension:
public static IServiceCollection AddMediator(this IServiceCollection services,
params Assembly[] assemblies)
{
services.AddMediatR(assemblies);
return services;
}
DbContext register:
services.AddDbContext<ApplicationDbContext>((provider, options) =>
{
options.UseSqlServer(configuration["ConnectionStrings:Cnn"],
b =>
{
b.MigrationsAssembly(typeof(ApplicationDbContext).Assembly.FullName);
b.MigrationsHistoryTable("__ApplicationDbContextMigrationHistory",
"dbo");
})
.EnableSensitiveDataLogging()
.EnableDetailedErrors();
options.AddInterceptors(
new DomainEventPublishingInterceptor(provider.GetRequiredService<IMediator>())
);
});
and finally after rasing any event I have a Notification handler:
public class PushRequestEventHandler:INotificationHandler<ProductApproved>
{
private readonly ApplicationDbContext _db;
public PushRequestEventHandler(ApplicationDbContext db)
{
_db = db;
}
public async Task Handle(ProductApproved notification, CancellationToken cancellationToken)
{
var categories= await _db.categories.ToListAsync(cancellationToken);
var products= await _db.Products
.Include(x=>x.ProductSpecs)
.SingleOrDefaultAsync(s => s.Id == notification.Id, cancellationToken);
// here the second call (products) throws the above mentioned error
// if I only have one db call then no error throws.
}
}
And also MultipleActiveResultSets is true.
