The instance of entity type 'Item' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked

Question

I am aware that such question has already been asked, but solution did not help me.

[Fact]
public async Task UpdateAsync()
{
    string newTitle = \"newTitle1\";         


        

Answer 1

Numerous issues I've been running into have one nasty root. In a nutshell: I've learned the hard way why dbContext is scoped rather than singleton. Here is Store type, but the issue was the same. Here is simplified test initialization code

public TestBase()
{
    services = new ServiceCollection();
    storeContext = StoreContextMock.ConfigureStoreContext(services, output);
    serviceProvider = services.BuildServiceProvider();
}
public static StoreContext ConfigureStoreContext(IServiceCollection services)
{
    services.AddDbContext(c =>
        c.UseInMemoryDatabase(Guid.NewGuid().ToString()).UseQueryTrackingBehavior(QueryTrackingBehavior.NoTracking));

    var serviceProvider = services.BuildServiceProvider();
    var storeContext = serviceProvider.GetRequiredService();
    storeContext .Stores.Add(new Store { Title = "John's store", Address = "NY", Description = "Electronics best deals", SellerId = "john@mail.com" });
    storeContext .Stores.Add(new Store { Title = "Jennifer's store", Address = "Sydney", Description = "Fashion", SellerId = "jennifer@mail.com" });
    storeContext .SaveChanges();
    return storeContext ;
}

I reread error and finally noticed the main word

The instance of entity type 'Store' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked

So there has to be some orphan tracked instance preventing me from working with store. I did not save any references to s1 or s2, so it must be storeContext storing references on inserted objects even after leaving scope of their declaration and initialization. That's why I was unable update variables normally and also why my 'queried' from db objects had all their navigation properties assigned (lazy loading has little to do with this). The following code resolved all my issues.

public static StoreContext ConfigureStoreContext(IServiceCollection services)
{
    services.AddDbContext(c =>
        c.UseInMemoryDatabase(Guid.NewGuid().ToString()).UseQueryTrackingBehavior(QueryTrackingBehavior.NoTracking));

    var serviceProvider = services.BuildServiceProvider();
    var storeContext = serviceProvider.GetRequiredService();
    var s1 = new Store { Title = "John's store", Address = "NY", Description = "Electronics best deals", SellerId = "john@mail.com" };
    var s2 = new Store { Title = "Jennifer's store", Address = "Sydney", Description = "Fashion", SellerId = "jennifer@mail.com" }
    storeContext .Stores.Add(s1);
    storeContext .Stores.Add(s2);
    storeContext .Entry(s1).State = EntityState.Detached;
    storeContext .Entry(s2).State = EntityState.Detached;
    storeContext .SaveChanges();
    return storeContext ;
}

That is one of many reasons why dbContext should be limited by a scope. Thanks for the hint.