Generic Entity Configuration

Extensions Methods

EntityFrameworkExtensions.cs

public interface IEntityMappingConfiguration  
{  
    void Map(ModelBuilder builder);  
}

public abstract class EntityMappingConfiguration<T> : IEntityMappingConfiguration<T> where T : class  
{  
    public abstract void Map(EntityTypeBuilder<T> builder);  
  
    public void Map(ModelBuilder builder)  
    {        Map(builder.Entity<T>());  
    }
}  
  
public interface IEntityMappingConfiguration<T> : IEntityMappingConfiguration where T : class  
{  
    void Map(EntityTypeBuilder<T> builder);  
}

public static class ModelBuilderExtensions  
{  
    private static IEnumerable<Type> GetMappingTypes(this Assembly assembly, Type mappingInterface)  
    {
        return assembly.GetTypes().Where(x => !x.IsAbstract && x.GetInterfaces().Any(y => IntrospectionExtensions.GetTypeInfo(y).IsGenericType && y.GetGenericTypeDefinition() == mappingInterface));  
    }  
    
    public static void AddEntityConfigurationsFromAssembly(this ModelBuilder modelBuilder, Assembly assembly)  
    {        
        var mappingTypes = assembly.GetMappingTypes(typeof(IEntityMappingConfiguration<>));  
        
        foreach (var config in mappingTypes.Select(Activator.CreateInstance).Cast<IEntityMappingConfiguration>())  
        {            
            config.Map(modelBuilder);  
        }    
	}
}

DbContext Configuration

ApplicationDbContext.cs

public class ApplicationDbContext : DbContext
{  
    public ApplicationDbContext(DbContextOptions options) : base(options)  
    {    
    }
    
	protected override void OnModelCreating(ModelBuilder modelBuilder)  
	{  
	    base.OnModelCreating(modelBuilder);  
	    modelBuilder.AddEntityConfigurationsFromAssembly(GetType().Assembly);  
	}
}

Per-entity Configuration & Customisation

Simple Example

AuditEventEntityConfiguration.cs

public class AuditEventEntityConfiguration : EntityMappingConfiguration<AuditEvent>  
{  
    public override void Map(EntityTypeBuilder<AuditEvent> builder)  
    {        
	    builder            
		    .HasKey(p => p.Id);
    }  
}

More Complex Example

OrganizationEntityConfiguration.cs

public class OrganizationEntityConfiguration : EntityMappingConfiguration<Organization>
{
    public override void Map(EntityTypeBuilder<Organization> builder)
    {
        builder
            .HasKey(p => p.Id);

        builder
            .Property(p => p.Name)
            .HasMaxLength(100)
            .IsRequired();

        builder
            .HasIndex(p => p.Name)
            .IsUnique();

        builder
            .OwnsOne(p => p.FeatureFlag);

        builder
            .Property(b => b.TriggerWords)
            .HasConversion(
                v => JsonSerializer.Serialize(v, (JsonSerializerOptions) null),
                v => JsonSerializer.Deserialize<List<string>>(v, (JsonSerializerOptions) null),
                new ValueComparer<List<string>>(
                    (c1, c2) => c1.SequenceEqual(c2),
                    c => c.Aggregate(0, (a, v) => HashCode.Combine(a, v.GetHashCode())),
                    c => c.ToList()))
            .HasColumnType("jsonb");
    }
}