I have a domain model specifying the interfaces or my domain and I'm using DI to hook it up to an entity framework 4 repository implementation. In my domain I have the following:
public interface IInboundGateway : IGateway
{
ICollection<IInboundNumber> InboundNumbers { get; set; }
}
I then have my entity framework model that has generated the InboundGateway class:
public partial class InboundGateway : EntityObject
{
public EntityCollection<InboundNumber> InboundNumbers { get; set; }
}
In order to implement the IInboundGateway inteface I created a partial InboundGateway class.
public partial class InboundGateway : IInboundGateway
{
}
Eventhough EntityCollection<> implements ICollection<> and InboundNumber implements IInboundNumber I am getting an error reporting that InboundGateway does not implement interface IInboundGateway.InboundNumbers because InboundGateway.InboundNumbers does not have the matching return type ICollection<IInboundNumber>
Im pretty certain this is mental as EntityCollection does implement ICollection and InboundNumber does implement IInboundNumber.
Any help would be massively appreciated thanks.
You have to be aware that EntityCollection<InboundNumber> is a sub type of ICollection<InboundNumber> but is NOT a subtype of ICollection<IInboundNumber>. These are 2 different types and are not related.
so in the entity object class you have:
public EntityCollection<InboundNumber> InboundNumbers { get; set; }
While the comopiler expects you to have:
public ICollection<IInboundNumber> InboundNumbers { get; set; }
If you could turn your EntityObjects to POCO, part of the problem would be solved since POCO classes using ICollection for their navigation properties by default. Also, you need to change your interface like this:
public interface IInboundGateway : IGateway {
ICollection InboundNumbers { get; set; }
}
Related
In Entity Framework 6, given class A and derived class B: A, I would like to load entities A into instances of B without having to code for each property.
So given:
public class A
{
public Guid AId { get; set; }
public string Value { get; set; }
}
public class B: A
{
[NotMapped]
public string OtherValue { get; set; }
}
public MyDbContext: DbContext
{
public DbSet<A> As { get; set; }
}
I would like to:
using (MyDbContext db = new MyDbContext())
{
IEnumerable<B> Bs = db.As.LoadBsSomehow()
}
I'm guessing I could add DbSet<B> Bs { get; set; } and then in OnModelCreate I could override the table name to As perhaps. I'd like to avoid that if I can.
The purpose of doing this is that we need view models that need the underlying model plus some other properties and I don't want to mess up the models with all the different view model properties. This would simplify coding and maintenance for when the main model is changed -- the inheritance would automatically handle the changes in the derived class (view models).
I can then set the additional properties of the Bs in a Select or other method.
Also, I do NOT want to use reflection. I can code that up if I need it. I'd rather find out if EF 6 has the ability to do this natively.
UPDATE: I can do DbContext.Database.SqlQuery<T>. I would prefer to be able to use LINQ instead of writing SQL. I have no problem writing SQL, but LINQ is much more maintainable from a code perspective. Perhaps if I can use LINQ to create an IQueryable<B> and get the SQL for it?
I am trying to create a RESTful web service that returns a list of products using ASP.NET MVC4 Web API. Here is my controller class
public class ProductController : ApiController
{
public IEnumerable<Product> GetProducts()
{
WebCatalogContext dbcontext = DatabaseConfig.Instance.Context;
List<Product> plist = dbcontext.Products.ToList();
return plist;
}
}
When I run my service and call the following URL from my browser :/api/Product, I get System.Runtime.Serialization.SerializationException. I looked into my plist object and there is no problem with it.
Here is my data model:
[DataContract(Name = "p")]
[Serializable]
public class Product
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[DataMember(Name = "id")]
public int Id { get; set; }
[Required, MaxLength(50)]
[DataMember(Name = "ti")]
public string Title { get; set; }
[Required]
[DataMember(Name = "de")]
public string Description { get; set; }
[Required]
[DataMember(Name = "ph")]
public string PhotoURL { get; set; }
[DataMember(Name = "ca")]
public virtual ProductCategory Category { get; set; }
}
[DataContract(Name="pc")]
[Serializable]
public class ProductCategory
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[DataMember(Name="id")]
public int Id { get; set; }
[DataMember(Name="nm")]
public string Name { get; set; }
}
When I remove the reference to ProductCategory from my Product class, all things work just fine. But, when I include it I get the following exception.
Type 'System.Data.Entity.DynamicProxies.Product_664E9A0AA1F165A26C342B508BFFF1279FD3FE059285225BDA19F407A29A9CAD' with data contract name 'Product_664E9A0AA1F165A26C342B508BFFF1279FD3FE059285225BDA19F407A29A9CAD:http://schemas.datacontract.org/2004/07/System.Data.Entity.DynamicProxies' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.
Any idea about what I am missing?
Regards
Entity Framework has wrapped your POCO with an EF Proxy POCO so it can perform lazy loading - this uses the Virtual attribute to create a 'lazy-loadable' navigation property. I expect that is where the serialization error comes from.
You could make a new class and map the POCO to that - then pass the DTO style class from the controller. I've never returned an EF object directly from the API (I always map to some something else) so I don't know another option.
EF POCO to DTO (data transfer object) is relatively painless if you use a tool like http://valueinjecter.codeplex.com/ or http://automapper.org/
To support Lazy Loading for navigation properties which is declared as virtual, EF will generate the proxies for any models which have navigation properties which leads to this kind of exception.
For very simple application, you can use model from EF as DTOs (if having no navigation properties), but for complex application, you should do separate and differ between DTOs and domain models. It should not be mapping 1:1 between DTO and domain model.
Therefore, in your case, you create more DTO model for Web API layer, it will be fine.
I have an abstract base class for a few entities I'm defining. One of those derived entities is actually a non-abstract base class to another entity.
Following this code:
public abstract class BaseReportEntry {
public int ReportEntryId { get; set;}
public int ReportBundleId { get; set; } //FK
public virtual ReportBundle ReportBunde { get; set; }
}
//A few different simple pocos like this one
public PerformanceReportEntry : BaseReportEntry {
public int PerformanceAbsolute { get; set; }
public double PerformanceRelative { get; set; }
}
//And one with a second level of inheritance
public ByPeriodPerformanceReportEntry : PerformanceReportEntry {
public string Period { get; set; }
}
I'm using a base EntityTypeConfiguration:
public class BaseReportEntryMap<TReportEntry> : EntityTypeConfiguration<TReportEntry>
where TReportEntry : BaseReportEntry
{
public BaseReportEntryMap()
{
this.HasKey(e => e.ReportEntryId);
this.HasRequired(e => e.ReportsBundle)
.WithMany()
.HasForeignKey(e => e.ReportsBundleId);
}
}
Presumably this works fine for the one-level of inheritance but throw the following error for that one case where it has a second level:
The foreign key component 'ReportsBundleId' is not a declared property on type 'ByPeriodPerformanceReportEntry'
public class ByPeriodPerformanceReportEntryMap : BaseReportEntryMap<ByPeriodPerformanceReportEntry>
{
public ByPeriodPerformanceReportEntryMap ()
: base()
{
this.Property(e => e.Period).IsRequired();
this.Map(m =>
{
m.MapInheritedProperties();
m.ToTable("ByPeriodPerformanceReportEntries");
});
}
}
Here's ReportBundle class if needed
public class ReportsBundle
{
public int ReportsBundleId { get; set; }
public virtual ICollection<PerformanceReportEntry> PerformanceReportEntries{ get; set; }
public virtual ICollection<ByPeriodPerformanceReportEntry> ByPeriodPerformanceReportEntries{ get; set; }
}
The problem is not so much the second level of inheritance but that PerformanceReportEntry (the base of ByPeriodPerformanceReportEntry) is an entity while BaseReportEntry (the base of PerformanceReportEntry) is not.
Your mapping would work if PerformanceReportEntry would not be an entity - i.e. its mapping is not added to the model builder configuration and you have no DbSet for this type and it would not occur in a navigation collection in ReportsBundle.
Deriving the configuration from BaseReportEntryMap<ByPeriodPerformanceReportEntry> is not possible in this case - and it is not necessary because the mapping for the base properties already happened by the BaseReportEntryMap<PerformanceReportEntry>. Therefore you can use
public class ByPeriodPerformanceReportEntryMap
: EntityTypeConfiguration<ByPeriodPerformanceReportEntry>
But I have doubt that the resulting model is as you would expect it. I don't know what the PerformanceReportEntries and ByPeriodPerformanceReportEntries collections in ReportsBundle are supposed to express. Do you expect that ByPeriodPerformanceReportEntries is a collection filtered by the subtype? Do you expect that PerformanceReportEntries contains only the ReportsEntries that are PerformanceReportEntrys but not ByPeriodPerformanceReportEntrys? Do you expect that PerformanceReportEntries contains all entries including the ByPeriodPerformanceReportEntries?
Anyway, BaseReportEntry.ReportBundle is a navigation property mapped in PerformanceReportEntry (not in ByPeriodPerformanceReportEntry). That means that the inverse navigation property in class ReportsBundle must refer to PerformanceReportEntry which is the PerformanceReportEntries navigation collection. ByPeriodPerformanceReportEntries will introduce a second one-to-many relationship between ReportsBundle and ByPeriodPerformanceReportEntry (without a navigation property in ByPeriodPerformanceReportEntry). The inverse navigation property of ByPeriodPerformanceReportEntries will NOT be BaseReportEntry.ReportBundle.
My feeling is that you should not have the ReportsBundle.ByPeriodPerformanceReportEntries collection, but I am not sure what you want to achieve exactly.
Edit
Refering to your comment that you only have these two Report types your mapping is way too complicated in my opinion. I would do the following:
Remove the BaseReportEntry class and move its properties into PerformanceReportEntry. It makes no sense to have a base class that only one single other class derives from.
Remove the ByPeriodPerformanceReportEntries from ReportsBundle, so that ReportsBundle will be:
public class ReportsBundle
{
public int ReportsBundleId { get; set; }
public virtual ICollection<PerformanceReportEntry>
PerformanceReportEntries { get; set; }
}
Remove the BaseReportEntryMap and move the mapping into PerformanceReportEntryMap. Derive this map from EntityTypeConfiguration<PerformanceReportEntry>.
Correct the mapping. Currently it is wrong because you don't specify the inverse navigation property in WithMany. PerformanceReportEntryMap should look like this:
public class PerformanceReportEntryMap
: EntityTypeConfiguration<PerformanceReportEntry>
{
public PerformanceReportEntryMap()
{
this.HasKey(e => e.ReportEntryId);
this.HasRequired(e => e.ReportsBundle)
.WithMany(b => b.PerformanceReportEntries)
.HasForeignKey(e => e.ReportsBundleId);
}
}
Derive ByPeriodPerformanceReportEntryMap from EntityTypeConfiguration<ByPeriodPerformanceReportEntry> and specify only mappings for properties that are declared in ByPeriodPerformanceReportEntry, not again for the base properties. That already happened in PerformanceReportEntryMap. You don't need and can't specify it again because it will cause exactly the exception you had.
Use Table-Per-Hierarchy (TPH) inheritance instead of Table-Per-Concrete-Type (TPC), especially if you only have a few properties declared in ByPeriodPerformanceReportEntry. TPC is more difficult to use because it has problems with database-generated identities and with polymorphic associations (which you have in your relationship between PerformanceReportEntry and ReportsBundle). The problems are explained in more details here. TPH instead offers the best performance. ByPeriodPerformanceReportEntryMap would then look like this:
public class ByPeriodPerformanceReportEntryMap
: EntityTypeConfiguration<ByPeriodPerformanceReportEntry>
{
public ByPeriodPerformanceReportEntryMap()
{
this.Property(e => e.Period).IsRequired();
}
}
No explicit configuration for TPH is necessary because it is the default inheritance mapping.
I am starting MVC4 with VS2012. I am also using EF5 with the "Database First" method of creating my classes.
However because the generated glasses can be regenerated I cannot put the Data Annotation details to assist with validation.
I have seen some code snippets that use MetaData and partial classes but I was wondering if anyone knows of a small compilable example that I can look at and pull apart to better understand how the vasious classes interlink.
Many many thanks for any help.
Dave
You can achieve what you need through extending models. Suppose that EF generated the following entity class for you:
namespace YourSolution
{
using System;
using System.Collections.Generic;
public partial class News
{
public int ID { get; set; }
public string Title { get; set; }
public int UserID { get; set; }
public virtual UserProfile User{ get; set; }
}
}
and you want do some work arounds to preserve your you data annotations and attributes. So, follow these steps:
First, add two classes some where (wherever you want, but it's better to be in Models) like the following:
namespace YourSolution
{
[MetadataType(typeof(NewsAttribs))]
public partial class News
{
// leave it empty.
}
public class NewsAttribs
{
// Your attribs will come here.
}
}
then add what properties and attributes you want to the second class - NewsAttribs here. :
public class NewsAttrib
{
[Display(Name = "News title")]
[Required(ErrorMessage = "Please enter the news title.")]
public string Title { get; set; }
// and other properties you want...
}
Notes:
1) The namespace of the generated entity class and your classes must be the same - here YourSolution.
2) your first class must be partial and its name must be the same as EF generated class.
Go through this and your attribs never been lost again ...
Using MVC3 and Entity Framework.
Am trying to get validation flowing from data model
Question: On an entity framework save, how can I automatically put in the [MetadataType tag below for my buddy class?
[EdmEntityTypeAttribute(NamespaceName="ModelValidationTestModel", Name="Person")]
[Serializable()]
[DataContractAttribute(IsReference=true)]
[MetadataType(typeof(Person_Validation))] // I want EF to put this line in automatically
public partial class Person : EntityObject
...
[Bind(Exclude="PersonID")]
public class Person_Validation
{
[Required]
public string FirstName { get; set; }
[Required]
public string LastName { get; set; }
[Required]
public int Age { get; set; }
[Required]
public string Email { get; set; }
}
Using example from: http://weblogs.asp.net/scottgu/archive/2010/01/15/asp-net-mvc-2-model-validation.aspx
I think the best option is not to mess with the class generated by EF. Instead define your own partial class:
[MetadataType(typeof(Person_Validation))]
public partial class Person
{
//rest of class may be empty
}
You can do this in the same file as the Person_Validation class if you like.
It's not automatic, but it is safe (your changes won't get lost). This approach will work with any code generation framework (that uses partial classes), not just EF.
Data Annotations/attributes are baked at compile time and you cannot add them dynamically. I would recommend you to avoid passing/getting your EF models to/from the views. You should be using view models which are classes specifically tailored to the needs of a given view. It is those view models that will handle the would handle view specific validations such required, format, ...). You could then use AutoMapper to have your controller map between your view models and the EF models.