EF Core Configuring Complex Types

Question

I'm learning C# at the moment with .NET Core and EF Core for working with database.

Now I'm at the point where I got stuck configuring my entities.

I have written the following classes:

public class Customer
{
    #region Properties
    public Guid CustomerID { get; set; }
    ...
    public Address Address { get; set; }
    #endregion

    public Customer()
    {
        Address = new Address();
    }
}

public class CustomerConfiguration : IEntityTypeConfiguration<Customer>
{
    public void Configure(EntityTypeBuilder<Customer> builder)
    {
        //Primary Key
        builder.HasKey(c => c.CustomerID);

        //Complex Types
        builder.OwnsOne<Address>("Address");
    }
}

public class Employee
{
    #region Properties
    public Guid EmployeeID { get; set; }
    ...
    public Address Address { get; set; }
    #endregion

    public Employee()
    {
        Address = new Address();
    }
}

public class EmployeeConfiguration : IEntityTypeConfiguration<Employee>
{
    public void Configure(EntityTypeBuilder<Employee> builder)
    {
        //Primary Key
        builder.HasKey(c => c.EmployeeID);

        //Complex Types
        builder.OwnsOne<Address>("Address");
    }
}

public class Address
{
    public string Street { get; set; }
    public string ZipCode { get; set; }
    public string City { get; set; }
    public State State { get; set; }
    public Country Country { get; set; }
}

I need to configure Address class with Fluent API that Address.Street is for Customer and Employee MaxLength = 50?

Is it possible to configure it for both at the same time? Or do I need to configure it for each entity?

Thanks for your help!

Answer 1

The valid answer of @Gert Arnold demonstrates, how to accomplish what you want for all of your target entities in a centralized way.

In case you want to keep the information in your configuration classes, then you can define it there instead (but it could be a bit more redundant, depending on the case):

public class CustomerConfiguration : IEntityTypeConfiguration<Customer>
{
    public void Configure(EntityTypeBuilder<Customer> builder)
    {
        //Primary Key
        builder.HasKey(c => c.CustomerID);

        //Complex Types
        builder.OwnsOne(e => e.Address)
            .Property(e => e.Street)
            .HasMaxLength(50);
    }
}

public class EmployeeConfiguration : IEntityTypeConfiguration<Employee>
{
    public void Configure(EntityTypeBuilder<Employee> builder)
    {
        //Primary Key
        builder.HasKey(c => c.EmployeeID);

        //Complex Types
        builder.OwnsOne(e => e.Address)
            .Property(e => e.Street)
            .HasMaxLength(42); // or 50 if you want
    }
}

Answer 2

You can set all kinds of attributes of model types at once because they're easily accessible by modelBuilder.Model.GetEntityTypes(). Setting max length of owned type properties can be done like so:

var ownedAddresses = modelBuilder.Model.GetEntityTypes()
    .Where(t => t.IsOwned() && t.ClrType == typeof(Address))
    .ToList();
foreach (var address in ownedAddresses)
{
    address.FindProperty("Street").SetMaxLength(50);
}

...after the owned types have been registered to the model builder, i.e. after you added the type configurations.

Of course, the Where(t => t.IsOwned() predicate is redundant here. It's just to show another way to find owned types.