Adding entities using AddRange method does not refresh entity ID

Question

I am using EF Core 1.1.1. I have noticed when i add IEnumerable<Entity> using AddRange method and then call SaveChanges() then entities gets saved in the database however their ID does not get refreshed.

Code below does not refresh ID after SaveChanges(). Note i am passing requests as IEnumerable

    public async Task Post([FromBody]IEnumerable<string> values)
    {
        var requests = values.Select(x => new Test()
        {
            Name = x,
            Status = "Init"
        });

        await _dbContext.Tests.AddRangeAsync(requests).ConfigureAwait(false);
        await _dbContext.SaveChangesAsync().ConfigureAwait(false);

        foreach (var r in requests)
        {
            var id = r.ID;
        }
    }

Code below does not refresh ID after SaveChanges(). Note i am passing request.ToList() as a parameter to AddRange method

    public async Task Post([FromBody]IEnumerable<string> values)
    {
        var requests = values.Select(x => new Test()
        {
            Name = x,
            Status = "Init"
        });

        await _dbContext.Tests.AddRangeAsync(requests.ToList()).ConfigureAwait(false);
        await _dbContext.SaveChangesAsync().ConfigureAwait(false);

        foreach (var r in requests)
        {
            var id = r.ID;
        }
    }

Code below does refresh ID after SaveChanges(). Note I am calling ToList() after selecting values.

    public async Task Post([FromBody]IEnumerable<string> values)
    {
        var requests = values.Select(x => new Test()
        {
            Name = x,
            Status = "Init"
        }).ToList();   //<------ ToList() or ToArray() would work

        await _dbContext.Tests.AddRangeAsync(requests).ConfigureAwait(false);
        await _dbContext.SaveChangesAsync().ConfigureAwait(false);

        foreach (var r in requests)
        {
            var id = r.ID;
        }
    }

I am not sure if this is a bug in EF or this is how it supposed to work. I understand IEnumerable is lazy and List and Array are eager, but if AddRange method is taking IEnumerable as parameter then it should work regardless.

It's not EF Core fault. In the "not working" cases you are just foreach-ing new Test objects. — Ivan Stoev
– Ivan Stoev, Commented Mar 31, 2017 at 19:39
Thanks for saving my life! Did you find a fix for this? I'm currently using ef core 2.0 and this problem persists, at least with your solution I can retrieve the ids. @LP13 — wOvalle
– wOvalle, Commented Dec 9, 2017 at 3:15
Ditto! This is really helpful. Still seeing this in EF Core 2.1 but .ToArray() works. Would like to know why this is happening tho. — BenjiFB
– BenjiFB, Commented Sep 19, 2018 at 1:06

drowhunter · Accepted Answer · 2020-08-25 02:48:25Z

2

As Ivan states the reason you are not seeing the id's is that in the Non working cases you are enumerating new test objects.

If you place a break point inside the enumerable you will see that during your for each it creates new Test objects at that time. These are NOT the same objects that were place in the database.

You are actually enumerating the IEnumerable twice

public async Task Post([FromBody]IEnumerable<string> values)
{
    var requests = values.Select(x => { 
        
        //place break point here
        new Test()
        {
            Name = x,
            Status = "Init"
        }
    });

    await _dbContext.Tests.AddRangeAsync(requests.ToList()).ConfigureAwait (false);
    await _dbContext.SaveChangesAsync().ConfigureAwait(false);

    foreach (var r in requests)
    {
        var id = r.ID;
    }
}

answered Aug 25, 2020 at 2:48

drowhunter

3992 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Adding entities using AddRange method does not refresh entity ID

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related