Support SaveChanges while iterating a query

using (var db = new UnicornStoreContext())
{
    foreach (var p in db.Products)
    {
        db.Products.Add(new Product { DisplayName = "Copy of " + p.DisplayName });
        db.SaveChanges();
    }
}

SqlException: New transaction is not allowed because there are other threads running in the session. System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)

Obviously this is a bit of an anti-pattern since the SaveChanges should go outside the loop, but this is just a boiled down repro from a case where it does make sense (calling another component like Idenitty that saves to the database as part of the API call).

foreach (var role in db.PreApprovals
    .Where(p => p.UserEmail == user.Email)
    .Select(p => p.Role))
{
    await UserManager.AddToRoleAsync(user, role);
}

Model from the repro…

    public class UnicornStoreContext : DbContext
    {
        public DbSet<Product> Products { get; set; }

        protected override void OnConfiguring(DbContextOptions options)
        {
            options.UseSqlServer("Server=(localdb)\\v11.0;Database=UnicornStore;Trusted_Connection=True;MultipleActiveResultSets=true");
        }
    }

    public class Product
    {
        public int ProductId { get; set; }
        public string DisplayName { get; set; }
        public string Description { get; set; }
        public decimal MSRP { get; set; }
        public decimal CurrentPrice { get; set; }
    }

[ajcvickers]

@dazbradbury I read through to understand again. I don’t think it’s something we are planning to revisit.

[dazbradbury]

Understood. We’re happy to rely on the analyser, I guess if anyone else runs into this they can comment / follow this issue. Thanks for letting us know in any case so we can plan around it.