ef core code first generic inheritance mapping - c#

All Positions have a Location (Many-to-1).
Different Location types have different Position types
Model:
public abstract class Location
{
public int Id { get; set; }
public string Name { get; set; }
public int AreaId { get; set; }
public Area Area { get; set; }
public byte[] ConcurrencyToken { get; set; }
}
public abstract class Location<T> : Location where T : Position
{
public ICollection<T> Positions { get; set; } = new List<T>();
}
public class Bay : Location<BayRow> {}
public class StandardLocation : Location<Position> {}
public class Position
{
public int Id { get; set; }
public int? Place { get; set; }
public int LocationId { get; set; }
public Location Location { get; set; }
public byte[] ConcurrencyToken { get; set; }
}
public class BayRow : Position
{
public int? Row { get; set; }
}
The above is abbreviated, there are many more implementations of each. All locations extend the generic class.
Mapping:
modelBuilder.Entity<Position>(entity =>
{
entity.ToTable("Position")
.HasDiscriminator<int>("Type")
.HasValue<Position>(1)
.HasValue<BayRow>(2);
entity.Property(x => x.ConcurrencyToken).IsConcurrencyToken();
//THIS IS THE ISSUE*
entity.HasOne(x => x.Location as Location<Position>).WithMany(x => x.Positions).HasForeignKey(x => x.LocationId);
});
modelBuilder.Entity<Location>(entity =>
{
entity.HasIndex(x => new {x.Name, x.AreaId}).IsUnique(true);
entity.Property(x => x.ConcurrencyToken).IsConcurrencyToken();
entity.HasDiscriminator<int>("Type")
.HasValue<StandardLocation>(1)
.HasValue<Bay<BayRow>>(2)
});
modelBuilder.Entity<Bay<BayRow>>(entity =>
{
entity.HasMany(x => x.Positions).WithOne(x => x.Location as Bay<BayRow>)
.HasForeignKey(x => x.LocationId).OnDelete(DeleteBehavior.Cascade);
});
modelBuilder.Entity<BayRow>(entity =>
{
entity.Property(x => x.Row).HasColumnName("Row");
});
*The non-generic Location does not have positions
I've tried adding the collection to the base Location purely for mapping, to avoid ef duplicating/aliasing each location Impl i.e. BayId as LocationId.
publiic ICollection<Position> Positions { get; set; }
and with the new keyword to hide the base collection, but ef projects 2 collections...
public new ICollection<T> Positions { get; set; }
Any insight would be much appreciated.

I'm not sure this is supported by Entity Framework, without generating two tables - one for Bay and one for StandardLocation.
You might try this as a workaround.
public interface ITypedPosition<T> where T: Position
{
IEnumerable<T> Positions { get; }
}
public abstract class Location
{
public int Id { get; set; }
public string Name { get; set; }
public int AreaId { get; set; }
public Area Area { get; set; }
public byte[] ConcurrencyToken { get; set; }
public ICollection<Position> Positions { get; set; }
}
public class Bay : Location, ITypedPosition<BayRow>
{
IEnumerable<BayRow> ITypedPosition<BayRow>.Positions => base.Positions.OfType<BayRow>();
}
public class StandardLocation : Location, ITypedPosition<Position>
{
IEnumerable<Position> ITypedPosition<Position>.Positions => base.Positions.OfType<Position>();
}

Related

Automapper Sub Property Mapping

I have a situation where I need to map a sub-collection of items within an object to a collection of items in another object. I am essentially trying to flatten the object for use by a consuming system.
Given the following entity classes:
public class PersonEntity
{
public int Id { get; set; }
public virtual ICollection<OutcomeEntity> Outcomes { get; set; }
}
public class OutcomeEntity
{
public int Id { get; set; }
public bool Outcome { get; set; }
public virtual ICollection<GradeEntity> Grades { get; set; }
public PersonEntity Person { get; set; }
}
public class GradeEntity
{
public int Id { get; set; }
public string Grade { get; set; }
public string MarkersComment { get; set; }
public OutcomeEntity Outcome { get; set; }
}
I need to map the OutcomeEntity and GradeEntity to the following flattened structure where there can be many outcomes, containing many different grades:
public class PersonDTO
{
public int PersonId { get; set; }
public virtual ICollection<GradeDTO> Grades { get; set; }
}
public class GradeDTO
{
public int OutcomeId { get; set; }
public int GradeId { get; set; }
public string Grade { get; set; }
public string MarkersComment { get; set; }
}
Basically, for every Outcome in the collection, I want to iterate over the grades within it and create a new object (GradeDTO).
I have attempted to create a basic map, but I simply cannot get my head around the sub-properties.
To create one collection from many you can use SelectMany extension method. With this method and the following configuration AutoMapper will create PersonDto from PersonEntity.
Mapper.Initialize(cfg =>
{
cfg.CreateMap<GradeEntity, GradeDTO>()
.ForMember(dto => dto.GradeId, x => x.MapFrom(g => g.Id))
.ForMember(dto => dto.OutcomeId, x => x.MapFrom(g => g.Outcome.Id));
cfg.CreateMap<PersonEntity, PersonDTO>()
.ForMember(dto => dto.PersonId, x => x.MapFrom(p => p.Id))
.ForMember(dto => dto.Grades, x => x.MapFrom(p => p.Outcomes.SelectMany(o => o.Grades)));
});

Map a flatten SQL response to an object containing lists of lists with Automapper

The error message that I'm receiving at runtime is:
Unmapped members were found. Review the types and members below.
Add a custom mapping expression, ignore, add a custom resolver, or modify the source/destination type
For no matching constructor, add a no-arg ctor, add optional arguments, or map all of the constructor parameters
List'1 -> MobileRoot (Destination member list)
System.Collections.Generic.List'1[[Strata.CS.Jazz.Biz.Dashboard.MobileInfo, Strata.CS.Jazz.Biz, Version=2019.10.0.0, Culture=neutral, PublicKeyToken=null]] -> Strata.Jazz.Web.Controllers.MobileController+MobileRoot (Destination member list)
Unmapped properties:
Users
From what I can tell from the error message is that AutoMapper needs to know how to handle the ForMember Users create in the MobileRoot, and then propagate that for each of the subsequent lists down the chain. Can anyone tell me how to do this efficiently using AutoMapper? I know how to do this with Linq using GroupBy and Select, so it is my thought that this should be do-able with AutoMapper.
The query I have returns this class:
public class MobileInfo
{
public string NameFull { get; set; }
public string EmailAddress { get; set; }
public string SolutionName { get; set; }
public int SortOrder { get; set; }
public string Name { get; set; }
public bool IsLegacy { get; set; }
public string Description { get; set; }
public string WidgetName { get; set; }
public int Row { get; set; }
public int Col { get; set; }
public int Height { get; set; }
public int Width { get; set; }
public string WidgetClassName { get; set; }
public string Data { get; set; }
}
I would like to use Automapper with profiles to have it return this:
internal class MobileRoot
{
public IEnumerable<MobileUser> Users { get; set; }
}
internal class MobileUser
{
public string NameFull { get; set; }
public string EmailAddress { get; set; }
public IEnumerable<MobileSolution> Solutions { get; set; }
}
internal class MobileSolution
{
public string Solution { get; set; } // MobileInfo.SolutionName
public int SortOrder { get; set; }
public IEnumerable<MobileDashboard> Dashboards { get; set; }
}
internal class MobileDashboard
{
public string Dashboard { get; set; } // MobileInfo.Name
public bool IsLegacy { get; set; }
public string Description { get; set; }
public IEnumerable<MobileWidget> Widgets { get; set; }
}
internal class MobileWidget
{
public string Widget { get; set; } // MobileInfo.WidgetName
public int Row { get; set; }
public int Col { get; set; }
public int Height { get; set; }
public int Width { get; set; }
public string WidgetClassName { get; set; }
public string Data { get; set; }
}
The Profiles I have defined so far are:
public class ProfileMobileRoot : Profile
{
public ProfileMobileRoot()
{
CreateMap<MobileInfo, MobileRoot>();
}
}
public class ProfileMobileUser : Profile
{
public ProfileMobileUser()
{
CreateMap<MobileInfo, MobileUser>();
}
}
public class ProfileMobileSolution : Profile
{
public ProfileMobileSolution()
{
CreateMap<MobileInfo, MobileSolution>();
}
}
public class ProfileMobileDashboard : Profile
{
public ProfileMobileDashboard()
{
CreateMap<MobileInfo, MobileRoot>();
}
}
public class ProfileMobileWidget : Profile
{
public ProfileMobileWidget()
{
CreateMap<MobileInfo, MobileWidget>();
}
}
You can do something like below. It's a little late so my solution isn't so sophisticated... but it works ;)
public class ProfileMobileRoot : Profile
{
public ProfileMobileRoot()
{
CreateMap<MobileInfo, MobileWidget>()
.ForMember(x=>x.Name, opt=>opt.MapFrom(x=>x.WidgetName));
CreateMap<IEnumerable<MobileInfo>, IEnumerable<MobileDashboard>>()
.ConvertUsing<DashboardConverter>();
CreateMap<IEnumerable<MobileInfo>, IEnumerable<MobileSolution>>()
.ConvertUsing<SolutionConverter>();
CreateMap<IEnumerable<MobileInfo>, IEnumerable<MobileUser>>()
.ConvertUsing<UserConverter>();
CreateMap<IEnumerable<MobileInfo>, MobileRoot>()
.ForMember(x => x.Users, opt => opt.MapFrom(x => x.ToList()));
}
}
class UserConverter : ITypeConverter<IEnumerable<MobileInfo>, IEnumerable<MobileUser>>
{
public IEnumerable<MobileUser> Convert(IEnumerable<MobileInfo> source, IEnumerable<MobileUser> destination, ResolutionContext context)
{
var groups = source.GroupBy(x => new { x.NameFull, x.EmailAddress});
foreach (var v in groups)
{
yield return new MobileUser()
{
EmailAddress = v.Key.EmailAddress,
NameFull = v.Key.NameFull,
Solutions = context.Mapper.Map<IEnumerable<MobileSolution>>(source.Where(x =>
v.Key.NameFull == x.NameFull && v.Key.EmailAddress== x.EmailAddress)).ToList()
};
}
}
}
class SolutionConverter : ITypeConverter<IEnumerable<MobileInfo>, IEnumerable<MobileSolution>>
{
public IEnumerable<MobileSolution> Convert(IEnumerable<MobileInfo> source, IEnumerable<MobileSolution> destination, ResolutionContext context)
{
var groups = source.GroupBy(x => new { x.SolutionName, x.SortOrder});
foreach (var v in groups)
{
yield return new MobileSolution()
{
Solution = v.Key.SolutionName,
SortOrder = v.Key.SortOrder,
Dashboards= context.Mapper.Map<IEnumerable<MobileDashboard>>(source.Where(x =>
v.Key.SolutionName== x.SolutionName&& v.Key.SortOrder== x.SortOrder)).ToList()
};
}
}
}
class DashboardConverter : ITypeConverter<IEnumerable<MobileInfo>, IEnumerable<MobileDashboard>>
{
public IEnumerable<MobileDashboard> Convert(IEnumerable<MobileInfo> source, IEnumerable<MobileDashboard> destination, ResolutionContext context)
{
var groups = source.GroupBy(x => new {x.Name, x.IsLegacy, x.Description});
foreach (var v in groups)
{
yield return new MobileDashboard()
{
Dashboard = v.Key.Name,
Description = v.Key.Description,
IsLegacy = v.Key.IsLegacy,
Widgets = context.Mapper.Map<IEnumerable<MobileWidget>>(source.Where(x =>
v.Key.IsLegacy == x.IsLegacy && v.Key.Name == x.Name && v.Key.Description == x.Description))
};
}
}
}

AutoMapper with different children

I have an entity as Plan with multiple sub-plans (children), each of which could be null.
For the PlanDto, I am trying to load up a list of all children rather than having a separate property for each child like the entity.
I have already achieved it manually through a foreach loop but now I am trying to do it via AutoMapper, which is failing for some reason.
Entities:
public class Plan
{
public virtual int Id { get; set; }
public DateTime Date { get; set; }
public virtual PlanDetail PlanChild1 { get; set; }
public virtual ObservationCare PlanChild2 { get; set; }
}
public class PlanDetail
{
public virtual int Id { get; set; }
public virtual Plan Plan { get; set; }
public virtual string Description { get; set; }
}
public class ObservationCare
{
public virtual int Id { get; set; }
public virtual Plan Plan { get; set; }
public virtual string Description { get; set; }
}
DTOs:
public class PlanDto: EntityDto
{
public DateTime Date { get; set; }
public IEnumerable<ChildPlan> ChildPlan { get; set; }
}
public class ChildPlan : EntityDto
{
public ChildPlanType Type { get; set; }
}
public enum ChildPlanType
{
PlanDetail,
ObservationCare
}
AutoMapper config:
configuration.CreateMap<Plan, PlanDto>();
configuration.CreateMap<PlanDetail, ChildPlan>()
.ForMember(dto => dto.Type, options => options.MapFrom(p => ChildPlanType.PlanDetail));
configuration.CreateMap<ObservationCare, ChildPlan>()
.ForMember(dto => dto.Type, options => options.MapFrom(p => ChildPlanType.ObservationCare));
Mapping attempt:
var output = new List<PlanDto>();
var plans = await _planRepository.GetAll().ToList();
foreach (var plan in plans)
{
output.Add(ObjectMapper.Map<PlanDto>(plan));
}
I do not know why ChildPlan DTOs in the output list are always null!
You have to specify the mapping for PlanDto.ChildPlan:
configuration.CreateMap<Plan, PlanDto>()
.ForMember(dto => dto.ChildPlan,
options => options.MapFrom(
p => new object[] { p.PlanChild1, p.PlanChild2 }.Where(c => c != null)));
If you are using Entity Framework Core, you have to use eager-loading:
var plans = await _planRepository.GetAll()
.Include(p => p.PlanChild1)
.Include(p => p.PlanChild2)
.ToList();
There's also a simpler and more efficient way to map a list:
var output = ObjectMapper.Map<List<PlanDto>>(plans);

EF : custom logic to know which object to include/load

I have the following classes:
public class A
{
public Guid Id { get; set; } = Guid.NewGuid();
public ICollection<B> AllB { get; set; } = new List<B>();
public B Current { get; set; }
// other properties
}
public class B
{
public int Id { get; set; }
public Guid AId { get; set; }
public A A { get; set; }
// other properties
}
// in the DBContext
public DbSet<A> AllA { get; set; }
public IQueryable<A> AWithAllB
{
get
{
return AllA.Include(c => c.AllB);
}
}
protected override void OnModelCreating(ModelBuilder builder)
{
builder.Entity<A>().ToTable("A");
builder.Entity<A>().HasKey(h => h.Id);
builder.Entity<B>().ToTable("B");
builder.Entity<B>().HasKey(h => h.Id);
builder.Entity<B>().HasOne(h => h.A).WithMany().HasForeignKey(r => r.AId);
}
Basically, there are many B for one A.
What I struggle with is the property Current from A.
I want this property to be populated but with a custom logic to find which B to load.
In my case, it will be the instance of B with the highest Id that I want as Current. This logic will change in the future.
How can I achieve this?

Entity Framework One-To-Many

First of all I have these two models to store a post in two tables one for shared data and the other contains cultured data for English and Arabic
public class Post
{
public int Id { set; get; }
public bool Active { get; set; }
public bool Featured { get; set; }
public virtual ICollection<PostContent> Contents { get; set; }
}
public class PostContent
{
public int Id { set; get; }
public string Title { get; set; }
public string Summary { get; set; }
public string Details { get; set; }
[StringLength(2)]
public string Culture { get; set; }
public int PostId { get; set; }
[InverseProperty("PostId")]
public virtual Post Post{ set; get; }
}
Mapping
public class PostMap : EntityTypeConfiguration<Post>
{
public PostMap()
{
HasKey(p => p.Id);
Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
ToTable("Posts");
}
}
public class PostContentMap : EntityTypeConfiguration<PostContent>
{
public PostContentMap()
{
HasKey(p => p.Id);
Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
HasRequired(p => p.Post).WithMany(p => p.Contents).HasForeignKey(p=>p.PostId);
ToTable("PostContents");
}
}
I have two questions
1- Is these models are connected properly. Is there something else I need to do ?
2- I need to select all Posts with their contents where the culture of the content 'en' for example. I used this:
var res = context.Posts.Include(p => p.Contents.Single(c => c.Culture.Equals("en")));
and have this error:
The Include path expression must refer to a navigation property defined on the type. Use dotted paths for reference navigation properties and the Select operator for collection navigation properties.Parameter name: path
If you know you are not going to support more than two cultures then I would just add to your Post class.
public class Post
{
public Post()
{
Contents = new List<PostContent>();
}
public int Id { set; get; }
public bool Active { get; set; }
public bool Featured { get; set; }
public int? EnglishContentId { get;set;}
public int? ArabicContentId { get;set;}
PostContent EnglishContent {get;set;}
PostContent ArabicContent {get;set;}
}
public class PostContent
{
public int Id { set; get; }
public string Title { get; set; }
public string Summary { get; set; }
public string Details { get; set; }
[StringLength(2)]
public string Culture { get; set; }/*This property is not required*/
}
public class PostMap : EntityTypeConfiguration<Post>
{
public PostMap()
{
HasKey(p => p.Id);
Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
ToTable("Posts");
HasOptional(p => p.EnglishContent).WithMany().HasForeignKey(p=>p.EnglishContentId);
HasOptional(p => p.ArabicContent).WithMany().HasForeignKey(p=>p.ArabicContentId);
}
}
public class PostContentMap : EntityTypeConfiguration<PostContent>
{
public PostContentMap()
{
HasKey(p => p.Id);
Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
ToTable("PostContents");
}
}
The Above design will simplify your design and queries, will improve the performance alot.
But if you might have to support more cultures then you got the design and mapping right.
As far as EF 5, include does not allow filters, but I am not sure about EF 6.0
atleast you can get all posts that have english contents as follows
Add using System.Data.Entity;
var res = context.Posts.Include(p => p.Contents).Where(c => c.Contents.Any(cp=>cp.Culture.Equals("en")));

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