cincuranet
commented
1 month ago I'm not sure I understand what are you trying to achieve. But basically your Fields property is of type ParameterCollection<FieldScheme>, yet the backing field _fields is ICollection<FieldScheme>/List<FieldScheme>.
As I'm not sure what is your goal, it's hard say what direction to take. One option would be to have not mapped property for ParameterCollection<FieldScheme> and regular ICollection<FieldScheme> for rest of what EF is doing. Something like this:
using var db = new MyContext();
await db.Database.EnsureDeletedAsync();
await db.Database.EnsureCreatedAsync();
var contactScheme = new ObjectScheme()
{
Name = "test",
FriendlyFields = new(
[
new FieldScheme { Name = "test" }
]),
};
db.Set<ObjectScheme>().Add(contactScheme);
public interface IFriendlyId
{
public string FriendlyId { get; }
}
public class ParameterCollection<T> : IReadOnlyCollection<T> where T : IFriendlyId
{
private readonly Dictionary<string, T> _items;
public ParameterCollection(IEnumerable<T> parameters)
{
_items = new Dictionary<string, T>(parameters.Select(parameter => new KeyValuePair<string, T>(parameter.FriendlyId, parameter)));
}
public T this[string name] => _items[name];
public IEnumerator<T> GetEnumerator() => _items.Values.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => _items.Values.GetEnumerator();
public int Count => _items.Count;
}
public class FieldScheme : IFriendlyId
{
public Guid Id { get; set; }
public required string Name { get; init; }
public string FriendlyId => Name;
}
public class ObjectScheme
{
public Guid Id { get; set; }
public required string Name { get; init; }
private readonly ICollection<FieldScheme> _fields = new List<FieldScheme>();
public required ParameterCollection<FieldScheme> FriendlyFields
{
get => new(_fields);
init => _fields = new List<FieldScheme>(value);
}
public ICollection<FieldScheme> Fields
{
get => _fields;
init => _fields = value;
}
}
class MyContext : DbContext
{
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
base.OnConfiguring(optionsBuilder);
optionsBuilder.UseSqlite("Data Source=test.db");
optionsBuilder.LogTo(Console.WriteLine);
optionsBuilder.EnableSensitiveDataLogging();
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<ObjectScheme>(Configure);
void Configure(EntityTypeBuilder<ObjectScheme> builder)
{
builder.HasKey(t => t.Id);
builder.HasMany(t => t.Fields)
.WithMany();
builder.Property(t => t.Name).IsRequired();
builder.Ignore(x => x.FriendlyFields);
}
}
}
alex-samuilov
Hello everyone!
I introduced a custom collection for accessing parameters through its friendly ID -
ParameterCollection(in fact, the collection works with all entities that have this “friendly id”):And I'm trying to use it as a navigation collection for an
ObjectSchemeentity consisting of multipleFieldSchemes:Entity configuration is following:
My DbContext:
However, when adding an entity (
dbContext.ObjectSchemes.Add(contactScheme)), an exception is thrown:Adding conversion methods from
ListtoParameterCollectionalso doesn't give a positive result - they aren't even called.My model is:
As far as I can see, EF Core found a backing field (
_fields) in the navigation collection. But if you explicitly configure the entity to save the_fieldsfield instead of theFieldsproperty, the exception above isn't thrown.I would be glad for any advice on what I'm doing wrong.
Thank you in advance.
Additional information: EF Core version: 8.0.7 Database provider: Npgsql.EntityFrameworkCore.PostgreSQL, version 8.0.4 Target framework: .NET 8.0 Operating system: macOS Sonoma 14.5 IDE: Rider 2024.1