EF Core and Blazor Server - entity cannot be tracked

Question

Been using EF Core with Razor pages for a few years now, but Blazor with EF Core has me questioning myself on tasks that used to be simple. I'm creating a golf app, and I'm attempting to update a particular person's round of golf.

Having stumbled in the beginning, I have learned that using dependency injection for the dbContext in Blazor causes several errors including the one in my subject line. Instead, I'm using DI to inject an IDbContextFactory and creating a new context in each method of my services.

The following code updates a golfer's round. When editing, the user may change the course, teebox, or any of the 18 scores. I'm able to update the round once, but if I go back into the same round to edit it a second time I get the "cannot be tracked" "already tracking" error.

I've scoured the internet for possible reasons, I've tried .AsNoTracking() on my initial GetRound(), I've tried detaching the entry after SaveChangesAsync(), I've tried using the ChangeTracker to check whether I need to attach to the Round object being updated. Nothing I've done allows me to update the same round twice without doing a reload in between the first and second update.

I'll provide whatever code necessary, but I'll start with the offending code:

public async Task<bool> UpdateRoundAsync(RoundModel Round)
{
        var rtnVal = false;

        try
        {
            using (var _context = _dbFactory.CreateDbContext())
            {
                _context.Rounds.Attach(Round).State = EntityState.Modified;
                await _context.SaveChangesAsync();
                _context.Entry(Round).State = EntityState.Detached;

            }
            rtnVal = true;
        }
        catch (Exception ex)
        {
            Console.Write(ex.Message);
            throw;
        }

        return rtnVal;
}

When I run the above code, I see NOTHING in the change tracker as modified until I attach to the Round. Despite nothing being tracked, despite the dbContext being created new, then disposed, I still get an error that I'm already tracking the entity.

Help? What am I doing wrong?

Danny

UPDATE: Edited the repro as requested, but it did not change the issue - still unable to update the Round twice without a reload in between.

Answer 1

Caveat: I'm not happy posting this as an answer, but it does solve the problem for now. I won't mark it as THE answer until I understand more about EFCore and Blazor together.

I did find that I was making a call to get course details without telling EF that I didn't want it to track the entity, however, that still didn't fix the problem.

In the end, I simply forced the page to reload programmatically: NavMgr.NavigateTo("[same page]", true) after my update call. It feels very un-Blazor-like to do it this way, but ultimately I'm still learning Blazor and not getting much feedback on this post. I'm going to forage ahead, and hope that clarity comes down the road.