I would like to know, how could I, with AutoMapper, Map one Dto to multiple entities.
Lemme explain.
I've got one Dto, with an enum to describe its type (to avoid having multiple dtos)
Depending on that enum (RelationType here), I would like to map it to the correct Model (Entity, what ever, it's another object that I use in database).
public class BCardDto : IMappedDto
{
public long Id { get; set; }
public BCardRelationType RelationType { get; set; }
public long RelationId { get; set; }
}
Here are is my Model base:
public class BCardModel : IMappedDto
{
public long Id { get; set; }
}
And here the derived model :
public class CardBCardModel : BCardModel
{
// ormlite, ignore that
[Reference]
public CardModel Card { get; set; }
[ForeignKey(typeof(CardModel), ForeignKeyName = "fk_bcard_card")]
public long RelationId { get; set; }
}
How do I map my Dto to the correct Model depending on the enum i've given ?
(I don't wanna use Mapper.Map everywhere but I wanna let mapper do the runtime mapping job)
Here is how I do it for the Model -> Dto
cfg.CreateMap<CardBCardModel, BCardDto>()
.ForMember(s => s.RelationType, expression => expression.UseValue(BCardRelationType.Card))
.IncludeBase<BCardModel, BCardDto>();
Tell me if I do something wrong and explain me why please :)
Thanks by advance,
Blowa.
Let's say you have a setup wherein there is a base class and 2 classes which derive the base class:
public class ModelBase
{
public string Name { get; set; }
}
public class ModelOne : ModelBase { }
public class ModelTwo : ModelBase { }
Let's also say you have a DTO with an enum as below:
public class ModelDto
{
public string Name { get; set; }
public ModelType ModelType { get; set; }
}
public enum ModelType
{
One = 1,
Two = 2
}
So now the task is: How do I map the ModelDto to either ModelOne or ModelTwo depending on the value in ModelDto.ModelType property?
Here is how:
Mapper.Initialize(cfg => cfg.CreateMap<ModelDto, ModelBase>().ConstructUsing(x =>
{
switch (x.ModelType)
{
case ModelType.One:
return new ModelOne { Name = x.Name };
case ModelType.Two:
return new ModelTwo { Name = x.Name };
default:
throw new InvalidOperationException("Unknown ModelType...");
}
}));
Usage
var dto1 = new ModelDto { ModelType = ModelType.One, Name = "ModelOne" };
var dto2 = new ModelDto { ModelType = ModelType.Two, Name = "ModelTwo" };
var one = Mapper.Map<ModelBase>(dto1);
var two = Mapper.Map<ModelBase>(dto2);
Another way to do the mapping is by using dynamic:
public class PersonDto
{
public string Name { get; set; }
}
public class StudentDto : PersonDto
{
public int studentNumber { get; set; }
}
public class EmployeDto : PersonDto
{
public string EmployeId { get; set; }
}
public class Person
{
public string Name { get; set; }
}
public class Student : Person
{
public int StudentNumber { get; set; }
}
public class Employe : Person
{
public string EmployeId { get; set; }
}
Create Map by using:
Mapper.CreateMap<StudentDto, Student>();
Mapper.CreateMap<EmployeDto, Employe>();
Do the Mapping by:
try
{
var student = MapPerson((dynamic) studentDto);
var employe = MapPerson((dynamic) employeDto);
}
catch
{
throw new InvalidOperationException("Unknown ModelType...");
}
And define two Methods
public static Student MapPerson(StudentDto studentDto)
{
return Mapper.Map<StudentDto, Student>(studentDto);
}
public static Employe MapPerson(EmployeDto employeDto)
{
return Mapper.Map<EmployeDto, Employe>(employeDto);
}
The benefit is that you don't need a key and avoid the switch statement
Related
I need to validate an object and transport somekind of result to our frontend, using FluentValidation. Therefor we´ve decided to transport the whole object and give every property its validation errorcode, so the frontend can show for every property detail errors and texts.
Here an example for what I´m tring to. Here the Property class which holds the value of an property and its error-code.
public interface IErrorProperty
{
string ErrorCode { get; set; }
}
public class Property<T> : IErrorProperty
{
public T Value { get; set; }
public string ErrorCode { get; set; }
public Property(T value) => Value = value;
public Property() { }
}
And this are my ToValidate-Classes (examples):
public class Person
{
public Property<string> Name { get; set; } = new();
public Property<string> LastName { get; set; } = new();
}
public class Company
{
public Property<string> Name { get; set; } = new();
public Property<List<Person>> Employees { get; set; } = new();
}
Now I´ve got the following validators (also examples):
public class PersonValidator : AbstractValidator<Person>
{
public PersonValidator(string firstNameFromDb, string lastNameFromDb)
{
RuleFor(x => x.LastName.Value).Equal(lastNameFromDb).WithErrorCode(ErrorCodes.NotEqualWithDb.ToString());
RuleFor(x => x.Name.Value).Equal(firstNameFromDb).WithErrorCode(ErrorCodes.NotEqualWithDb.ToString());
}
}
public class CompanyValidator : AbstractValidator<Company>
{
public CompanyValidator(FluentValidation.AbstractValidator<Person> personValidator)
{
RuleFor(x => x.Name.Value).Equal("This is a company").WithErrorCode(ErrorCodes.NotEqualWithDefinition.ToString());
RuleFor(x => x.Employees.Value).ForEach(x => x.SetValidator(personValidator));
}
}
Now the goal is, to write the error-codes into the matching property. Therefor here is my BaseValidator:
public abstract class AbstractValidator<T> : FluentValidation.AbstractValidator<T>
{
public override ValidationResult Validate(ValidationContext<T> context)
{
var result = base.Validate(context);
var instance = context.InstanceToValidate;
foreach (var error in result.Errors)
{
var property = instance.GetType().GetProperty(error.PropertyName.Split('.').First())?.GetValue(instance) as IErrorProperty;
if (property != null)
property.ErrorCode = error.ErrorCode;
}
return result;
}
}
But the problem is: Both Person and Company does have the property Name and therefor the my AbstractValidator assumes that both properties are wrong. Finaly to my question: Is there a way to get the errors object? The property is in it but not to which type this property belongs.
I created the GenericAttribute.cs file in my Models
public class GenericAttributes<T>
{
public T Id { get; set; }
public bool IsActive { get; set; }
public DateTime CreatedDate { get; set; }
}
Now I want to add 'int id' field in my User Model
public class User
{
//here I want to add 'Id' field
public string UserId { get; set; }
public string password { get; set; }
public string UserType { get; set; }
public int EmployeeId { get; set; }
public virtual Employee employee { get; set; }
}
How should I do this? Please help
You can make GenericAttributes an interface so you can implement it where ever.
Such as;
public interface IGenericAttributes<T>
{
//properties
}
And use in your class declaration;
public class User : IGenericAttributes<int>
{
//properties
}
This will force your concrete type User to implement the properties of the interface.
You are getting some conflicting answers due to your naming convention. Any class of the form xxxAttribute is expected to be a subclass of the Attribute class. Attributes are metadata that you can attach to classes, fields, etc. Using reflection you can read these attributes, which is a powerful way to inform various APIs about how to interact with your custom classes - without inheritance or an interface.
If this sort of metadata is your intent, then Barr J's answer is correct. However, if your intent is for the GenericAttributes class to serve as a base class that you can inherit these properties from, then Tom Johnson is correct (although he did change GenericAttributes into an interface instead of a base class, but same result if all you have are properties like this). The latter is most likely what you are looking for.
I would suggest renaming GenericAttributes to something more descriptive, like BaseRecord or IRecord (as an interface), since User looks like data coming from or going to a database.
It would also be handy to have a non-generic version of the class/interface so that you can non-generically reference such records.
public class BaseRecord {
public Type IdType { get; }
private Object _id = null;
public Object Id {
get {
return _id;
}
set {
if(value != null) {
if(!IdType.IsAssignableFrom(value.GetType()))
throw new Exception("IdType mismatch");
}
_id = value;
}
}
public bool IsActive { get; set; }
public DateTime CreatedTime { get; set; }
public BaseRecord(Type idType)
{
if(idType == null) throw new ArgumentNullException("idType");
this.IdType = idType;
}
}
namespace Generic {
public class BaseRecord<T> : BaseRecord
{
new public T Id {
get { return (T)base.Id; }
set { base.Id = value; }
}
public BaseRecord() : base(typeof(T))
{
}
}
}
public class User : Generic.BaseRecord<int>
{}
public class OtherRecord : Generic.BaseRecord<string>
{}
// This inheritence scheme gives you the flexibility to non-generically reference record objects
// which can't be done if you only have generic base classes
BaseRecord r = new User();
r = new OtherRecord();
BaseRecord records[] = { new User(), new OtherRecord() };
To access the id for GenericAttributes class, you'll have to cast User object as base class type.
namespace SampleApp
{
class SampleProgram
{
static void Main(string[] args)
{
User User = new User() { Id = 1 };
var genericAttribute = (User as GenericAttributes<int>);
genericAttribute.Id = 2;
var genericAttributeId = genericAttribute.Id;
var classId = User.Id;
}
}
public class GenericAttributes<T>
{
public T Id { get; set; }
}
public class User : GenericAttributes<int>
{
public new int Id { get; set; }
}
}
I have an Generic Abstract Class with some properties like Id, Name, Status, this class inherits several catalogs.
My question is whether it is possible to create a method with a restriction for the catalogs that implement the Abstract Class.
I give some examples so that they understand what I want to do:
public abstract class AbsCatalog<T>
{
public T Id { get; set; }
public string Name { get; set; }
public bool Status { get; set; }
}
These are the classes that implement the abstract class
public class Agent : AbsCatalog<string>
{
public string Office { get; set; }
public Estado Estado { get; set; }
}
public class Models : AbsCatalog<int>
{
public int Year { get; set; }
public string Description { get; set; }
}
The method I want to implement is the following:
List<Agent> Agents = service.GetAgents();
string AgentsDescription = GetDescription<Agent>(Agents);
List<Model> Models = service.GetModels();
string ModelsDescription = GetDescription<Model>(Models);
private string GetDescription<T>(List<T> list) where T : AbsCatalog<T>
{
string description = string.Empty;
if (list.Exists(x => x.Id.ToString() == "0"))
description = "";
else
description = string.Join(", ", list.Where(x => x.Status).Select(x => x.Name).ToArray());
return description;
}
I think the only way is to use two generic type parameters here, for example:
private string GetDescription<T, U>(List<T> list) where T : AbsCatalog<U>
{
//snip
}
And then call it like this:
string AgentsDescription = GetDescription<Agent, string>(Agents);
I am trying to list some food items with a controller. I use Repository pattern with UnitOfWork for the data in another assembly and referenced it in a BaseApiController. The Data property is my UnitOfWork instance.
var result = Data.Food
.FindAll()
.Select(FoodItemViewModel.Create);
return result;
and here is my ViewModel:
public static Expression<Func<FoodItem, FoodItemViewModel>> Create
{
get
{
return fi => new FoodItemViewModel
{
Id = fi.Id,
Description = fi.Description,
DiaryEntries = fi.DiaryEntries
.Select(s => new DiaryEntityViewModel()
{
Id = s.Id,
Quantity = s.Quantity
}
};
}
}
But all I get is:
"The specified type member 'DiaryEntries' is not supported in LINQ to
Entities. Only initializers, entity members, and entity navigation
properties are supported."
My DiaryEntries member in the ViewModel is
IEnumerable<DiaryEntityViewModel>
and my DiaryEntries member in the Data instance is
IRepository<DiaryEntry>
and DiaryEntry is my model class
and here is my FoodItem model class:
public class FoodItem
{
private IEnumerable<Measure> measures;
private IEnumerable<DiaryEntry> diaryEntries;
public FoodItem()
{
this.measures = new HashSet<Measure>();
this.diaryEntries = new HashSet<DiaryEntry>();
}
public int Id { get; set; }
public string Description { get; set; }
public virtual IEnumerable<DiaryEntry> DiaryEntries
{
get
{
return this.diaryEntries;
}
set
{
this.diaryEntries = value;
}
}
public virtual IEnumerable<Measure> Measures
{
get
{
return this.measures;
}
set
{
this.measures = value;
}
}
}
Change you FoodItem class to the one below, IEnumerable<T> is not supported as a type for a navigation collection :
public class FoodItem
{
public FoodItem()
{
this.Measures = new HashSet<Measure>();
this.DiaryEntries = new HashSet<DiaryEntry>();
}
public int Id { get; set; }
public string Description { get; set; }
public virtual ICollection<DiaryEntry> DiaryEntries
{
get;
set;
}
public virtual ICollection<Measure> Measures
{
get;
set;
}
}
This is my model Heirarchy :
public interface INodeModel<T> : INodeModel
where T : struct
{
new T? ID { get; set; }
}
public interface INodeModel
{
object ID { get; set; }
string Name { get; set; }
}
public class NodeModel<T> : INodeModel<T>
where T : struct
{
public T? ID { get; set; }
public string Name { get; set; }
object INodeModel.ID
{
get
{
return ID;
}
set
{
ID = value as T?;
}
}
}
public class NodeDto<T> where T : struct
{
public T? ID { get; set; }
public string Name { get; set; }
}
and these are my mappings and test :
class Program
{
private static MapperConfiguration _mapperConfiguration;
static void Main(string[] args)
{
_mapperConfiguration = new MapperConfiguration(cfg =>
{
cfg.CreateMap(typeof(NodeDto<>), typeof(NodeModel<>));
cfg.CreateMap(typeof(NodeDto<>), typeof(INodeModel<>));
cfg.CreateMap(typeof(INodeModel<>), typeof(NodeModel<>));
});
var dto = new NodeDto<int> { ID = 1, Name = "Hi" };
var obj = _mapperConfiguration.CreateMapper().Map<INodeModel<int>>(dto);
Console.Write(obj.ID);
Console.ReadLine();
}
}
and here is the exception :
AutoMapper.AutoMapperMappingException:
Mapping types:
NodeDto1 -> INodeModel1 NodeDto`1[[System.Int32] ->
INodeModel`1[[System.Int32]
Message:
The interface has a conflicting property ID Parameter name: interfaceType
Stack:
at AutoMapper.Internal.ProxyGenerator.CreateProxyType(Type interfaceType)
at AutoMapper.Internal.ProxyGenerator.GetProxyType(Type interfaceType)
at AutoMapper.MappingEngine.CreateObject(ResolutionContext context)
AutoMapper is confused when creating a proxy implementation that you have two members with the same name in your interfaces. You're using shadowing, which is even harder. Rather than assume AutoMapper can make sense of this, which, good luck explaining to a new team member, I would instead make the interface class implementation explicit:
cfg.CreateMap(typeof(NodeDto<>), typeof(NodeModel<>));
cfg.CreateMap(typeof(NodeDto<>), typeof(INodeModel<>))
.ConvertUsing(typeof(NodeModelConverter<>));
cfg.CreateMap(typeof(INodeModel<>), typeof(NodeModel<>));
public class NodeModelConverter<T> :
ITypeConverter<NodeModel<T>, INodeModel<T>> where T : struct
{
public INodeModel<T> Convert(NodeModel<T> source, ResolutionContext context)
=> new NodeModelImpl {ID = source.ID, Name = source.Name};
private class NodeModelImpl : INodeModel<T>
{
public T? ID { get; set; }
public string Name { get; set; }
object INodeModel.ID
{
get { return ID; }
set { ID = (T?) value; }
}
}
}
No magic and completely explicit and obvious!