EF Core 3.0 In Memory DB Set Primary Key Next Rec Id

[aherrick]

In EF Core 2.2 In Memory DB we forced our next primary key using a method like this:

		public static void SetNextIdValueForTable(this DbContext context, Type tableType, int forcedNextIdValue = 0)
		{
			if (context == null)
			{
				throw new ArgumentNullException(nameof(context));
			}

			var cache = context.GetService<IValueGeneratorCache>();

			// We calculate what should be one less than the next ID value by taking the given value for ID and subtracting one if given
			// or we calculate the number of records already in the given table.
			var oneLessThanNextIdValue = forcedNextIdValue > 0
				? forcedNextIdValue - 1
				: context.Model.GetEntityTypes(tableType).FirstOrDefault()?.GetSeedData().Count();

			foreach (var keyProperty in context.Model.GetEntityTypes(tableType)
				.Select(e => e.FindPrimaryKey().Properties[0])
				.Where(p => p.ClrType == typeof(int)
							&& p.ValueGenerated == ValueGenerated.OnAdd))
			{
				var generator = (ResettableValueGenerator)cache.GetOrAdd(
					keyProperty,
					keyProperty.DeclaringEntityType,
					(_, __) => new ResettableValueGenerator());

				generator.SetNextIdValue(oneLessThanNextIdValue ?? 0);
			}
		}
	

	public class ResettableValueGenerator : ValueGenerator<int>
	{
		private int current;

		public override bool GeneratesTemporaryValues => false;

		public override int Next(EntityEntry entry)
			=> Interlocked.Increment(ref current);

		public void SetNextIdValue(int currentNumOfRecords) => current = currentNumOfRecords;
	}

In 3.0, it doesn't seem to work anymore. Then next record I insert is always PK 1.

Spike code sample:
EFCore3MemorySetRecId.zip

[ajcvickers]

@aherrick Given that this was a workaround for issues in-memory value generation which have been fixed in 3.0, can you provide some more details as to why it is that you still need to do this?

[aherrick]

we need a way to insert a record into a blank the in memory DB Table with a certain Primary Key.

[ajcvickers]

@aherrick That should work. If it doesn't, then please post a small, runnable project/solution that demonstrates the issue.

[aherrick]

its already posted above :)

[ajcvickers]

@aherrick Changing your code as follows works for me:

            // force next student id inserted to be 6
            // Not needed: _ctx.SetNextIdValueForTable(typeof(Student), 6);

            _ctx.Students.Add(new Student()
            {
                Id = 6,
                StudentName = "Andrew"
            });