Automapper projection results in empty collection for nested Dto - automapper

I have a .Net Core 2 webapi in which I am using automapper to map to Dtos. Everything works fine, except I am seeing an unexpected behaviour when I map an object to a Dto, and where the Dto also contains mappings for a collection. E.g
CreateMap<Order, OrderDto>();
CreateMap<Product, ProductDto>();
Where classes are like this
public partial class Order
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Product> Products{ get; set; }
public int ProductCount {return Products.Count;}
}
public partial class Product
{
public int Id { get; set; }
public int OrderId { get; set; }
public string Name { get; set; }
public string Description { get; set; }
}
The following works as expected;
The class is mapped, and the ProjectCount is correct in the Dto
public partial class OrderDto
{
public int Id { get; set; }
public virtual ICollection<Product> Products{ get; set; }
public int ProductCount{ get; set; }
}
_context.Orders.Include<>(Products).ProjectTo<>(OrderDto)
But doing the following, the productcount is always zero.
E.g. if I do this;
public partial class OrderDto
{
public int Id { get; set; }
public virtual ICollection<ProductDto> Products{ get; set; }
public int ProductCount{ get; set; }
}
public partial class ProductDto
{
public int Id { get; set; }
public int OrderId { get; set; }
public string Name { get; set; }
}
_context.Orders.Include<>(Products).ProjectTo<>(OrderDto)
Why does this happen, and how can I ensure that it doesnt? This is a real world example where I need a property which references the collection - and I need it in both the base and the Dto. I can do the following which works fine, but it doesnt appear that this should be how it works...
public partial class OrderDto
{
public int Id { get; set; }
public virtual ICollection<ProductDto> Products{ get; set; }
public int ProductCount {return Products.Count;}
}
public partial class ProductDto
{
public int Id { get; set; }
public string Name { get; set; }
}
_context.Orders.Include<>(Products).ProjectTo<>(OrderDto)

I profiled the SQL and found that Automapper changes the way the query is formed. Without the nested projection, two queries are made;
[Queries are more complex than this and use joins, but you get the idea]
Select Id from orders
Select Id,Name from products where productid in [select id from orders ]
With the nested projection, are executed for each nested Dto
Select Id from orders
Select Id,Name from products where id=1
Select Id,Name from products where id=2

Related

Autoquery servicestack ILeftJoin issue with table.id column

I have definition of autoquery dto defined as below:
[Route("/project/{ProjectId}/contracts/{ContractId}/items")]
public class QueryContractItem : QueryDb<ContractItem, ContractItemResponse>,
ILeftJoin<ContractItem, ContractItemEstimateItem>,
ILeftJoin<ContractItemEstimateItem, EstimateItem>,
ILeftJoin<ContractItemEstimateItem, ContractItemEstimateItemComponent>,
ILeftJoin<EstimateItem, EstimateComponent>,
ILeftJoin<EstimateItem, EstimateGroup>
{
public int ProjectId { get; set; }
public int ContractId { get; set; }
}
public class ContractItemResponse
{
// ...
public int ContractItemEstimateItemId { get; set; } // WRONGLY taken from ContractItemEstimateItemComponent.ContractItemEstimateItemId - PROBLEM
public int ContractItemEstimateItemEstimateItemId { get; set; } //value is taken correctly from ContractItemEstimateItem - CORRECT
public int ContractItemEstimateItemContractItemId { get; set; } //value is taken correctly from ContractItemEstimateItem - CORRECT
}
Not sure why during query execution the value of ContractItemEstimateItemId is taken from ContractItemEstimateItemComponent.ContractItemEstimateItemId (the value is not yet there).
Expected is that query will take a value for field ContractItemEstimateItemId from ContractItemEstimateItem.Id

Autmapper nested mapping

I have the following main class:
public class ResearchOutcome
{
public ResearchOutcomeCategory ResearchOutcomeCategory { get; set; }
public string? UniqueIdentifier { get; set; }
}
And the category class is:
public class ResearchOutcomeCategory
{
public int Id { get; set; }
public string Name { get; set; }
public string? Description { get; set; }
}
The View models for above classes are:
public class ResearchOutcomeDetailVm : IMapFrom<ResearchOutcome>
{
public int Id { get; set; }
public virtual ResearchOutcomeCategoryDetailVm ResearchOutcomeCategory { get; set; }
}
public class ResearchOutcomeCategoryDetailVm : IMapFrom<ResearchOutcomeCategory>
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
}
Now, I have used the following mapping profile:
// First this one
profile.CreateMap<ResearchOutcomeCategory, ResearchOutcomeCategoryDetailVm>();
profile.CreateMap<ResearchOutcome, ResearchOutcomeDetailVm>();
//Then I tried this one
profile.CreateMap<ResearchOutcome, ResearchOutcomeDetailVm>()
.ForMember(o => o.ResearchOutcomeCategory,
cat => cat.MapFrom( o => o.ResearchOutcomeCategory));
But the ResearchOutcomeCategory is always null. Any help would be appreciated.
After digging more, I identified that I was not "Including" the relevant item in the query, hence, the view model was always empty. Pretty dumb on my part :D
Regarding the mapping, if the properties (even complex ones) have the same names, then the mapper will map them automatically. So simply this line worked
profile.CreateMap<ResearchOutcomeCategory, ResearchOutcomeCategoryDetailVm>();
Hope it helps someone

Conversion failed,when using AutoQuery in ServiceStack

I have the following AutoQuery function.
[Route("/cars/search")]
public class SearchCars : QueryDb<Car, CarDto>
{
public List<int> EquipmentIds { get; set; }
public List<int> ManufacturerIds { get; set; }
public List<int> ColourIds { get; set; }
}
The function works, when I do the following:
Cars/Search?ColourIds=1&format=json
Cars/Search?ManufacturerIds=1&format=json
but when I try to use
Cars/Search?EquipmentIds=1&format=json
I get "Conversion failed when converting the varchar value '[1]' to data type int.".
The difference between these fields is that Car object can have multiple EquipmentIds, but only one ColourId and ManufacturerId.
public class Car
{
[AutoIncrement]
public int Id { get; set; }
public Colour Colour { get; set; }
[Required]
public int ColourId { get; set; }
public Manufacturer Manufacturer { get; set; }
[Required]
public int ManufacturerId { get; set; }
[Required]
public List<Equipment> Equipment { get; set; }
[Required]
public List<int> EquipmentId { get; set; }
}
Do I have to define for which attribute the different parameters should be assigned too?
AutoQuery works by constructing an RDBMS query based on implicit conventions which is used to construct an SQL query that runs on the RDBMS.
Complex Types in OrmLite data models are blobbed by default which means they can't be queried in the RDBMS with SQL, so you wont be able to query it with AutoQuery.
You could create a hybrid Custom AutoQuery Implementation where you can apply any custom logic to filter the results of the AutoQuery results, something like...
public class MyQueryServices : Service
{
public IAutoQueryDb AutoQuery { get; set; }
//Override with custom implementation
public object Any(SearchCars query)
{
var equipmentIds = query.EquipmentIds;
query.EquipmentIds = null;
var q = AutoQuery.CreateQuery(query, base.Request);
var response = AutoQuery.Execute(query, q);
if (equipmentIds != null)
response.Results.RemoveAll(x => x.EquipmentId...);
return response.
}
}

EntityFramework : Invalid column name *_ID1

I am trying to implement DbContext for couple of tables called 'Employee' and 'Department'
Relationship between Employee and Department is many to one. i.e. department can have many employees.
Below are the EntityFramework classes I designed ( CodeFirst approach )
[Table("Employee")]
public class Employee
{
[DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[Column("Name")]
public string Name { get; set; }
[Column("Department_ID")]
public int Department_ID { get; set; }
public virtual Department Department { get; set; }
}
[Table("Department")]
public class Department
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
[Column("Name")]
public string Name { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
While adding Employee record I am getting below exception
"Invalid column name 'Department_ID1'."
I am not sure why EF is referring to Department_ID1. Do I need to add configuration in OnModelCreating method of DbContext?
I am using EF version 6.1.1
I've also gotten this problem in my EF one-many deals where the one has a List of the many property and my mapping didn't specify that property. For example take:
public class Notification
{
public long ID { get; set; }
public IList<NotificationRecipient> Recipients { get; set; }
}
then
public class NotificationRecipient
{
public long ID { get; set; }
public long NotificationID { get; set; }
public Notification Notification { get; set; }
}
Then in my mapping, the way that caused the Exception (the incorrect way):
builder.HasOne(x => x.Notification).WithMany()
.HasForeignKey(x => x.NotificationID);
What fixed it (the correct way) was specifying the WithMany property:
builder.HasOne(x => x.Notification).WithMany(x => x.Recipients)
.HasForeignKey(x => x.NotificationID);
Hi After spending some time I could fix this problem by using ForeignKey attribute on public virtual Department Department { get; set; } property of Employee class.
Please see below code.
[Table("Employee")]
public class Employee
{
[DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[Column("Name")]
public string Name { get; set; }
[Column("Department_ID")]
public int Department_ID { get; set; }
[ForeignKey("Department_ID")]
public virtual Department Department { get; set; }
}
This fixed my problem. Are there any other solution to fix this? Using fluent API?
For me, the issue was resolved by removing a (duplicate?) virtual property.
Using the OP's example:
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public int Department_ID { get; set; }
public virtual Department Department { get; set; }
}
public class Department
{
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
Turns into:
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public int Department_ID { get; set; }
}
public class Department
{
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
In my case I added a virtual property on top of the auto generated property
I fixed it by adding the NotMapped attribute to my property, or you could configure with fluent api
public partial class Control
{
[NotMapped]
public virtual ICollection<Control> Children { get => this.InverseParent; set => this.InverseParent = value; }
}
I had the same error, my issue was the FK was a long but I had it as an int in the model. EF generated a new column because it didn't match types on the FK so it assumed they weren't the same and went ahead with making another one but putting 1 at the end because there was already one with the proper name. Making sure the types matched resolved the issue for me.
This can be fixed simply by putting [NotMapped] annotation on your virtual properties.
public class Employee
{
[ForeignKey("Department")]
public int Department_ID
[NotMapped]
public virtual Department Department { get; set; }
}
And in you modelBuilder:
modelBuilder.Entity<Employee>(entity =>
{
entity.HasOne(e => e.Department);
});
Just flip this around if you want to call by Department.
We use the [NotMapped] annotation so that EF Core will disregard it when looking at your database.

EF Code First - Many To Many

I have a problem with devising a many to many relationship in code first. EF is creating the Junction table and associating the Fk's as I would expect, however when i try to access the User's MailingList collection, there are no entries.
I've implemented test data on Initialise via Seeding, the data is al present in the database.
I think the problem lies with the constructors for Users and MailingLists, but I'm uncertain. I want to be able to navigate the navigational property of User.MailingLists.
var user = db.Users.Find(1);
Console.WriteLine("{0}", user.EmailAddress); //This is Fine
Console.WriteLine("{0}", user.Address.PostCode); /This is Fine
foreach (MailingList ml in user.MailingLists) // this is 0
{
Console.WriteLine("{0}", ml.Name);
}
My model is below:-
public class User : IEntityBase
{
public User()
{
MailingLists = new List<MailingList>();
}
public int Id { get; set; }
public string Forename { get; set; }
public string Surname { get; set; }
public string EmailAddress { get; set; }
public DateTime? DateLastUpdated { get; set; }
public DateTime DateCreated { get; set; }
public bool IsDeleted { get; set; }
public virtual Address Address { get; set; }
public ICollection<MailingList> MailingLists { get; set; }
}
public class MailingList : IEntityBase
{
public MailingList()
{
Users = new List<User>();
}
public int Id { get; set; }
public string Name { get; set; }
public DateTime? DateLastUpdated { get; set; }
public DateTime DateCreated { get; set; }
public bool IsDeleted { get; set; }
public ICollection<User> Users { get; set; }
}
public class Address : IEntityBase
{
public int Id { get; set; }
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public string AddressLine3 { get; set; }
public string City { get; set; }
public string County { get; set; }
public string PostCode { get; set; }
public DateTime? DateLastUpdated { get; set; }
public DateTime DateCreated { get; set; }
public bool IsDeleted { get; set; }
}
Any suggestions welcome.
You are neither eager loading the MailingList entries with the query, nor fulfulling the requirements for a lazy loading proxy so there is no way EF can populate the collection.
To allow lazy loading, change the MailingList property to be virtual to allow the EF proxy to override it.
To use eager loading, use Include() (an extension method in System.Data.Entity) in the query to specify that the MailingList should be loaded.

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