Cannot access a disposed object. A common cause of this error is disposing a context

Question

I have written a simple application and when I navigate to my edit page the below error pops up.

Microsoft.EntityFrameworkCore.Query[10100]

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Answer 1

What I am about to post is NOT the answer to this particular question. But it is related so just to save somebody headache I am posting it. I was encountering this same error

System.ObjectDisposedException: Cannot access a disposed object. etc

The following was the code with the bug (can you see it?):

[HttpGet("processs/oxxo-spei/ticket-email/{paymentIdx}")]
public StatusCodeResult ProcessOxxoSpeiTicketEmailAsync(string paymentIdx)
{
    var paymentId = paymentIdx.DecodeRef();
            
    var response = _orderEngine.ProcessOxxoSpeiTicketEmailAsync(paymentId);

    return StatusCode(200);
}

The following change fixed it:

[HttpGet("processs/oxxo-spei/ticket-email/{paymentIdx}")]
public async Task ProcessOxxoSpeiTicketEmailAsync(string paymentIdx)
{
    var paymentId = paymentIdx.DecodeRef();
            
    var response = await _orderEngine.ProcessOxxoSpeiTicketEmailAsync(paymentId);
                // ^^^^I HAD FORGOTTEN TO PUT AWAIT
    return StatusCode(200);
}

Yes that's right I had forgotten to put "await" before a function that used an EF Core dbcontext. Adding 'await' fixed it. So easy to miss it, especially if you're tired and under deadline.