I have a DTO which has a collection within it of another DTO which I populate server-side and send to the client. However, this inner DTO collection is not returned to the client.
I believe I need to use the [Include] and [Association] attributes so that WCF RIA services knows what to do, however my issue with this is there is no real association as such between the main DTO and the inner DTO collection, I am just using it to aggregate data from various sources for return to the client.
Is my understanding wrong in what I am trying to achieve, if not how do I get WCF RIA to send this inner DTO collection.
I should add that I am using automapper and want to achieve it using such.
Here is an example, I want to send back to the client in one chunk;
The competencies that the employee has.
The competencies that the employee requires for their job.
The GAP, which is the difference between 1 and 2.
public class CompetencyRequirementsDto
{
[Key]
public string CompanyId { get; set; }
[Key]
public string EmployeeNo { get; set; }
public string JobId { get; set; }
[Include]
[Association("EmployeeCompetencies","CompanyId, EmployeeNo","CompanyId, EmployeeNo")]
public IList<EmployeeCompetencyDto> EmployeeCompetencies { get; set; }
[Include]
[Association("JobCompetencies","JobId, CompanyId","JobId, CompanyId")]
public IList<JobCompetencyDto> JobCompetencies { get; set; }
[Include]
[Association("CompetencyGap", "JobId, CompanyId", "JobId, CompanyId")]
public IList<JobCompetencyDto> CompetencyGap { get; set; }
} }
Now item 1 works fine, but 2 and 3 don't? What I have found is that my DTO is created ok server side but when it gets to the client CompetencyGap(even when it has no values) has
been given JobCompetencies values.
If you are using ADO.Net Entity data model and using RIA Services against them then you have got an option to create associated metadata.
So to get the reference entities at you client side we need to modify both the our corresponding meta-data and as well as well the function of the domain service class which is fetching your data .
Here I am giving an example...
1. Just add [Include] attribute at the the top of the referenced data for example.
[MetadataTypeAttribute(typeof(Customer.CustomerMetadata))]
public partial class Customer
{
// This class allows you to attach custom attributes to properties
// of the Customer class.
//
// For example, the following marks the Xyz property as a
// required property and specifies the format for valid values:
// [Required]
// [RegularExpression("[A-Z][A-Za-z0-9]*")]
// [StringLength(32)]
// public string Xyz { get; set; }
internal sealed class CustomerMetadata
{
// Metadata classes are not meant to be instantiated.
private CustomerMetadata()
{
}
public int CustomerID { get; set; }
public string EmailAddress { get; set; }
public string FullName { get; set; }
[Include]
public EntityCollection<Order> Orders { get; set; }
public string Password { get; set; }
}
}
2. Modify the function in the domain service and add include there also for example.
public IQueryable<Customer> GetCustomers()
{
var res = this.ObjectContext.Customers.Include("Orders");
return res;
}
In your case the first part is done you just need to modify your domain service query to get reference entities.
Related
I am using Hot towel template and extended functionality of it by using breeze. I have used breeze.partial-entities.js file to conver breeze entities to proper dtos that can be used by knockout observables as shown below.
function dtoToEntityMapper(dto) {
var keyValue = dto[keyName];
var entity = manager.getEntityByKey(entityName, keyValue);
if (!entity) {
// We don't have it, so create it as a partial
extendWith = $.extend({ }, extendWith || defaultExtension);
extendWith[keyName] = keyValue;
entity = manager.createEntity(entityName, extendWith);
}
mapToEntity(entity, dto);
entity.entityAspect.setUnchanged();
return entity;
}
For few of the entities it is working properly and getting breeze data converted to entities but for one of the entity implementation is failing. Model for the same is given as below.
public class StandardResourceProperty
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public int StandardResourceId{ get; set; }
public int InputTypeId{ get; set; }
public int ListGroupId{ get; set; }
public string Format{ get; set; }
public string Calculation{ get; set; }
public bool Required{ get; set; }
public int MinSize{ get; set; }
public int MaxSize{ get; set; }
public string DefaultValue{ get; set; }
public string Comment { get; set; }
public virtual StandardResource AssociatedStandardResource { get; set; }
public virtual List AssociatedList { get; set; }
}
The error i am getting is
TypeError: this[propertyName] is not a function
[Break On This Error]
thispropertyName;
breeze.debug.js (line 13157)
]
with code
proto.setProperty = function(propertyName, value) {
this[propertyName](value);
// allow set property chaining.
return this;
};
Please let me know . What can be possible issue with the implementation also , it would be great if i can get more suggestion on how to debug and trace such issues.
Let's back up. I do not understand what you mean by "convert breeze entities to proper dtos that can be used by knockout observables". Breeze entities are already configured as KO observables (assuming you are using the default Breeze model library configuration). What are you trying to do?
I suspect you are following along with the Code Camper Jumpstart course where it does a getSessionPartials projection query. That query (like all projections) returns DTOs - not entities - and maps them with the dtoToEntityMapper method into Session entities.
The CCJS dtoToEntityMapper method cannot be used with entities. It is for converting from a DTO to an Entity and takes DTOs - not entities - as input.
Goodbye to dtoEntityMapper
The dtoToEntityMapper method pre-dates the ability of Breeze to automate projection-to-entity mapping by adding .toType('StandardResourceProperty') to your projection query.
Here is what the CCJS getSessionPartials query could look like now:
var query = EntityQuery
.from('Sessions')
.select('id, title, code, speakerId, trackId, timeSlotId, roomId, level, tags')
.orderBy(orderBy.session)
.toType('Session');
If you go this way, be sure to set the default state of the isPartial flag to true in the custom constructor (see model.js)
metadataStore.registerEntityTypeCtor(
'Session', function () { this.isPartial = true; }, sessionInitializer);
Note that this.isPartial = true is the reverse of the CCJS example where the default was false.
Make sure that you set isPartial(false) when you query or create a full entity. In CCJS there are two places to do that: in the success-callback of getSessionById AND in createSession which would become:
var createSession = function () {
return manager.createEntity(entityNames.session, {isPartial: false});
};
This is my model on the server side. I don't want to use Entity Framework, how would I generate BreezeJS metadata from the server. Breeze Metadata Format found here http://www.breezejs.com/documentation/breeze-metadata-format doesn't work.
public class User
{
public string Id { get; set; }
public string Name { get; set; }
public List<App> Apps { get; set; }
}
public class App
{
public string Id { get; set; }
public string Name { get; set; }
public Dictionary<string, string> Info { get; set; }
}
Did anyone try complex objects (nested object) similar to above one without using EF.
Using Breeze Metdata API or OData ?
Look at this example http://www.breezejs.com/samples/nodb it should give you a clue.
I'm using entity framework and I figured out that it ain't able to serialize the output of
EDM Objects. For now I'm using Northwind Products-table. SO thereforth I'm forced to cast the Object to another and are using the .Cast but it doesn't work.
The only solution I have is to property by property do it manually in my code, but I'm thinking - there must be a better way!
For god's sake - it is 2013! And this Entity seems like a good idea in the beginning but it has so many gotchas and constraints that it actually hinders more than it helps, but anyway the EDMX diagrams are nice!
Anybody who has a better solution to casting the objects?
POCO
public class Product
{
public int ProductID { get; set; }
public string ProductName { get; set; }
//public Nullable<int> SupplierID { get; set; }
//public Nullable<int> CategoryID { get; set; }
public string QuantityPerUnit { get; set; }
public Nullable<decimal> UnitPrice { get; set; }
public Nullable<short> UnitsInStock { get; set; }
public Nullable<short> UnitsOnOrder { get; set; }
public Nullable<short> ReorderLevel { get; set; }
//public bool Discontinued { get; set; }
public Category Category { get; set; }
//public ICollection<Order_Detail> Order_Details { get; set; }
//public Supplier Supplier { get; set; }
}
View Model
public class ProductsViewModel
{
public List<POCO.Product> Products { get; set; }
public ProductsViewModel()
{
using (NorthwindEntities dNorthwindEntities = new NorthwindEntities())
{
this.Products = dNorthwindEntities.Products.Cast<POCO.Product>().ToList();
Web api controller:
public class ProductsController : ApiController
{
public List<Product> GetAllProducts()
{
var viewmodel = new ProductsViewModel();
return viewmodel.Products;
}
1.
You can use frameworks like AutoMapper to handle Entities to ViewModel / DTO mapping automatically.
2.
Using Entities in the View (even in their POCO form) is not recommended for couple of reasons:
Security: Sending entities back to the client/view may expose more data than you intended.
Serialization: Since your entities usually contain reference to another entities and those entities may contain a reference back to the (parent) entity, you have to configure your serializer to handle this situation otherwise you'll get Circular Dependency Exception.
Incompatibility: The structure of your entity may not be compatible with what your view/client needs to render itself. Sometimes your view just needs a simple string while the entity holds this data in a much complex way hence the view needs to 'extract' it and you end up with a view full of unnecessary entity-drill-down code.
I am struggling with this issue:
I have a list of NHibernate objects called "Project". These objects contain a lazy - loaded list of "Branches". I am trying to pass a list of Projects to a WCF service so I am using AutoMapper to transform them to flat objects.
The problem is that even though the destination objects called "ProjectContract" does not contain a list of Branches, Automapper still invokes this collection and a lot of queries are made to the database because NHibernate fires the lazy - loading and loads the Branches collection for each project.
Here are the classes and the mapping:
public class Project
{
public virtual int ID
{
get;
set;
}
public virtual string Name { get; set; }
public virtual string Description { get; set; }
public virtual IList<Branch> Branches { get; set; }
}
[DataContract]
public class ProjectContract
{
[DataMember]
public virtual int ID
{
get;
set;
}
[DataMember]
public virtual string Name { get; set; }
[DataMember]
public virtual string Description { get; set; }
}
public class ProjectMappings : Profile
{
protected override void Configure()
{
Mapper.CreateMap<Project, ProjectContract>();
}
}
My question is: Is there a way to tell AutoMapper to not touch the "Branches" collection because I don't care about it and that is a proxy that will trigger many database calls?
I temporarily fixed this with MaxDepth(0), but there are other entities where I have collections that I want to transfer, and collections that I don't want to be touched, like this one. In that case, MaxDepth(0) will not work.
Thank you,
Cosmin
Yes, The AutoMapper Ignore function.
Mapper.CreateMap<Source, Destination>()
.ForMember(dest => dest.SomeValuefff, opt => opt.Ignore());
I'm creating a WCF service that transfers entity objects created via entity framework. I have a User entity that maps to a User db table. There are certain User fields (Password, DateCreated, etc) that I don't want to expose to the client but, because they are non-nullable in the db, Visual Studio requires mappings. Setting these properties as private seems like a good workaround but these properties are converted to public when consumed by a client.
Is there a way around this, or a better approach to take? I'd rather avoid changing these fields at the db level just to make EF happy.
This sounds like to perfect opportunity to segregate the layers of the application. What you should do is create objects that are specific to the WCF layer that act only as Data Transfer Objects (DTO) to the outside consumers.
So, in your WCF service layer you make will your calls to your data access layer (Entity Framework) which retrieves User objects and you should return to your consumer objects constructed with only what you want to expose.
If you do this, you can explicitly control what you make visible to the outside world and also hide any implementation details about what you are doing from a data storage perspective.
As an extremely crude example, in your Entity Framework layer you might have this object:
namespace ACME.DataAccessLayer.Entities
{
public class User
{
public int Id { get; set; }
public string UserName { get; set; }
public string Password { get; set; }
public string Hash { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
}
namespace ACME.DataAccessLayer.Services
{
using ACME.DataAccessLayer.Entities;
public class UserService
{
public User GetUser(int id)
{
using (ACMEDataContext dc = new ACMEDataContext())
{
// psuedo code to return your user with Entity Framework
return dc.Users.FirstOrDefault(user => user.Id == id);
}
}
}
}
Then in your WCF later you might have an entity like:
namespace ACME.Services.DataTransferObjects
{
[DataContract]
public class User
{
[DataMember]
public int Id { get; set; }
[DataMember]
public string FirstName { get; set; }
[DataMember]
public string LastName { get; set; }
}
}
Then you would expose a service endpoint that would return back the DTO as such:
namespace ACME.Services
{
using ACME.DataAccessLayer.Services;
public class PublicWCFService : IUserService
{
public ACME.Services.DataTransferObjects.User GetUser(int userId)
{
ACME.DataAccessLayer.Entities.User entityFrameowrkUser = new UserService().GetUser(userId);
return new ACME.Services.DataTransferObjects.User
{
Id = entityFrameowrkUser.Id,
FirstName = entityFrameowrkUser.FirstName,
LastName = entityFrameowrkUser.LastName
};
}
}
}
Now what you would do is just return the DTO object which will not have any of the attributes, or methods that you may have in the real entities you use in your system.
With this approach, you can safely break the layers of the application into different layers (DLLs) that can easily be shared and extended.
This is a quick example, so let me know if there's anything further that would make this example more clear.
You could always implement IXmlSerializable on the entity object. Then, you would be able to dictate the structure of what is sent to the client (the client would get a different representation, obviously).
Either that, or if you can, add the DataContract attribute to the type, and the DataMember attribute to only the properties you wish to send over the wire.