Seeding data: The seed entity for entity type 'X' cannot be added because there was no value provided for the required property 'Id'.

I’m using EntityFrameworkCore 2.1.0-preview2-final

I try to seed data, this works:

modelBuilder.Entity<Dog>().HasData(new Dog[]
{
    new Dog() { Id = 1, Name = "Lucy", Age = 2 },
    new Dog() { Id = 2, Name = "Bella", Age = 3 },
    new Dog() { Id = 3, Name = "Daisy", Age = 5 },
});

this doesn’t:

modelBuilder.Entity<Dog>().HasData(new Dog[]
{
    new Dog() { Name = "Lucy", Age = 2 },
    new Dog() { Name = "Bella", Age = 3 },
    new Dog() { Name = "Daisy", Age = 5 },
});

And I get:

The seed entity for entity type ‘X’ cannot be added because there was no value provided for the required property ‘Id’.

public class BaseEntity
{
    public int Id { get; set; }
}

public class Dog : BaseEntity
{
    public string Name { get; set; }
    public int Age { get; set; }
}

I expected it to work even when skipping Id. Is it auto increment by default?

I wanted to get it working with Bogus:

var dogsIds = 0;
var testDogs = new Faker<Dog>().RuleFor(p => p.Name, f => f.Name.FirstName())
    .RuleFor(p => p.Age, f => DateTime.Now.Year - f.Person.DateOfBirth.Year)
    .RuleFor(p => p.Id, f => dogsIds++);

var dogs = testDogs.Generate(100);

modelBuilder.Entity<Dog>().HasData(dogs.ToArray());

[TheBauwssss]

Can the error message

System.InvalidOperationException: The seed entity for entity type ‘<class>’ cannot be added because there was no value provided for the required property ‘Id’.

be changed to

System.InvalidOperationException: The seed entity for entity type ‘<class>’ cannot be added because there was no value provided for the required property ‘Id’. Please note that 0 is not a valid value for the Id field. Please start incrementing from 1.

I just wasted a whole day trying to figure out why it was not working only to discover that I needed to start incrementing from 1 instead of 0.

[samodelkinvv]

Bruh…Same here.

The seed entity for entity type ‘Entity’ cannot be added because a non-zero value is required for property ‘Id’.

What’s the point of ModelBuilder if I should manually add autogenerated properties?! End up writing custom Seeder like I would create it with EF

Entity ent = new Entity(){
...my fields
}
dbContext.SaveChanges();

Then what’s the point in ModelBuilder.HasData() in the first place ?!