SaveChanges() throw exception, using OwnsOne in OnModelCreating() when initialize database

[hanslai]

An aggregateRoot class

public class Testcalss
    {
        public int Id { get; protected set; }
        public string Name { get; private set; }
        public string Description { get; private set; }
        public Address HomeAddress { get; private set; }

        private Testcalss()    {   }

        public static Testcalss Create(string name, string description)
        {
            return new Testcalss
            {
                Name = name,
                Description = description,
            };
        }
    }

A value object class

public class Address : ValueObject
{
        public string Country { get; private set; }
        public string ProvinceOrState { get; private set; }
        public string City { get; private set; }
        public string Street { get; private set; }
        public string Zipcode { get; private set; }

        private Address() { }
        public Address(string country = "", string provinceOrState = "", string city = "", string street = "", string zipcode = "")
        {
            Country = country;
            ProvinceOrState = provinceOrState;
            City = city;
            Street = street;
            Zipcode = zipcode;
        }
}

OnModelingCreating

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Testcalss>().HasKey(x => x.Id);
            modelBuilder.Entity<Testcalss>().OwnsOne(x => x.HomeAddress);
            base.OnModelCreating(modelBuilder);
        }

Full exceptions details (message and stack trace).

System.InvalidOperationException
  HResult=0x80131509
  Message=**The entity of 'Testcalss' is sharing the table 'Testcalss' with 'Testcalss.HomeAddress#Address', but there is no entity of this type with the same key value that has been marked as 'Added'.** Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the key values.
  Source=Microsoft.EntityFrameworkCore.Relational
  StackTrace:
   at Microsoft.EntityFrameworkCore.Update.Internal.ModificationCommandIdentityMap.Validate(Boolean sensitiveLoggingEnabled)
   at Microsoft.EntityFrameworkCore.Update.Internal.CommandBatchPreparer.CreateModificationCommands(IReadOnlyList`1 entries, Func`1 generateParameterName)
   at Microsoft.EntityFrameworkCore.Update.Internal.CommandBatchPreparer.<BatchCommands>d__8.MoveNext()
   at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(Tuple`2 parameters)
   at Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.Execute[TState,TResult](IExecutionStrategy strategy, TState state, Func`2 operation)
   at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(IEnumerable`1 commandBatches, IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Storage.RelationalDatabase.SaveChanges(IReadOnlyList`1 entries)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(IReadOnlyList`1 entriesToSave)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.DbContext.SaveChanges()
   at AIS.SharedKernel.Data.CommonDbContext.SaveChanges() in c:\Source\Repos\AIS\AIS.SharedKernel\Data\CommonDbContext.cs:line 42
   at AIS.HR.Data.Services.DatabaseInitializer.SeedTestDatabase(HRContext context) in c:\Source\Repos\AIS\AIS.HR\AIS.HR.Data\Services\DatabaseInitializer.cs:line 94
   at AIS.HR.API.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env, HRContext hrContext) in c:\Source\Repos\AIS\AIS.HR\AIS.HR.API\Startup.cs:line 95

Steps to reproduce

It is a asp.net core project, when initialize database in Startup class' Configure method with the following code.

            Testcalss t1 = Testcalss.Create("name1", "Desc1", 1);
            Testcalss t2 = Testcalss.Create("name2", "Desc2", 2);
            var testdata = new Testcalss[] { t1, t2 };
            context.AddRange(testdata);
            context.SaveChanges();

SaveChanges throw InvalidOperationExcetion.

Further technical details

EF Core version: Microsoft.AspNetCore.All Version="2.0.3"
Database Provider: (localdb)\mssqllocaldb
Operating system: Windows 10
IDE: (Visual Studio 2017 15.5.2)

[Tarig0]

You have to set the address property to an instance of the owned enitity.

[hanslai]

@Tarig0 Thanks, it make sense.
At the same time, it feels unnatural. For example, if Address’ parent entity is an Employee, then I have to set the Address of that employee when I create an Employee class. Maybe I need to rethink my model.