When accessing a nested object with the code below the following exception appears:
System.NotSupportedException: The left-hand side of the Equal operator must be a direct access to a
persisted property in Realm.
However in Objective C it seems that you can somehow query nested objects. Is it planned or are there are solutions to query nested objects in xamarin?
Realm.All<Person>().Where(p => p.Name.Firstname == "Test");
public class Person : RealmObject
{
public string Town { get; set; }
public PersonName Name { get; set; }
}
public class PersonName : RealmObject
{
public string Firstname { get; set; }
public string Lastname { get; set; }
}
This is a planned feature. You can keep track of the GitHub issue.
Related
Note: These classes are related, but not part of the same Aggregate (like PurchaseOrder and OrderLine) - so I do not have a navigation property from "One" to "Many".
=== Entities ===
public class One
{
public Guid Id { get; set; }
public string Name { get; set; }
}
public class Many
{
public Guid Id { get; set; }
public string Name { get; set; }
public Guid One { get; set; }
}
=== Contracts ===
public class OneWithMany
{
public Guid Id { get; set; }
public string Name { get; set; }
public IEnumerable<Many>? ManyRelatedObjects { get; set; }
}
I want to select all One objects and any related Many objects from DbSet/DbSet into OneWithMany.
To ensure I don't miss properties added in future I am using ProjectTo in AutoMapper - but I can't work out how to fit it into the equation.
Unfortunately, it seems Entity Framework does not support GroupJoin.
The solution is to do the projection and as much filtering as possible as two separate queries, and then combine them into a result in memory.
If you find EF related answers on the web related to GroupJoin make sure you check the example code to see if they are actually showing code working on arrays instead of DbSet.
I did some research but I couldn't find exactly what I wanted.
I have an endless menu. I have a MenuDTO and a MenuViewModel that I use for this menu. I had no problem matching between model and DTO, but am having trouble mapping DTO to ViewModel. Obviously I couldn't find the solution, can you help?
My MenuDTO Object
public class MenuDto : BaseDto
{
public string Name { get; set; }
public string Icon { get; set; }
public string Order { get; set; }
public string Url { get; set; }
public bool IsVisible { get; set; }
public int ParentId { get; set; }
public MenuDto ParentMenu { get; set; }
public List<MenuDto> Menus { get; set; }
}
And MenuViewModel
public class MenuViewModel
{
public int Id { get; set; }
public bool IsActive { get; set; }
public string Name { get; set; }
public string Icon { get; set; }
public string Order { get; set; }
public string Url { get; set; }
public bool IsVisible { get; set; }
public int ParentId { get; set; }
public MenuViewModel ParentMenu { get; set; }
public List<MenuViewModel> Menus { get; set; }
}
This is how I mapped the MenuDTO and MenuViewModel objects.
public class WebProfile : Profile
{
public WebProfile()
{
CreateMap<MenuDto, MenuViewModel>();
CreateMap<MenuViewModel, MenuDto>();
}
}
I call this way in the controller
var navMenuItems = _mapper.Map<List<MenuViewModel>(_menuService.GetNavMenus());
Although all fields are mapped, I get an error on the Menus field.
The error message I get is;
AutoMapperMappingException: Missing type map configuration or unsupported mapping.
Mapping types:
MenuDto -> MenuViewModel
BiPortal2020.Business.ServiceDTOs.Menu.MenuDto -> BiPortal2020.WebUI.Areas.Admin.Models.Menu.MenuViewModel
lambda_method(Closure , MenuDto , MenuViewModel , ResolutionContext )
AutoMapperMappingException: Error mapping types.
Mapping types:
Object -> List`1
System.Object -> System.Collections.Generic.List`1
The error message implies - AutoMapper, either cannot map between MenuDto and MenuViewModel, or it cannot locate the defined mappings.
I've tested your mappings and they are totally fine. So, what possibility remains is AutoMapper cannot locate your mappings.
I'm Assuming the Business Layer and UI Layer you mentioned in the comment section are two separate projects. Since the WebProfile is defined in the UI Layer, you have to tell AutoMapper that it should search that assembly to find the mappings. Since your mappings between Models and DTOs are working, I can guess you've already done the same for BusinessProfile which is defined in the Business Layer.
I don't know about your existing code, but you could do something like this - in the Startup.Configure method add/modify the following line -
services.AddAutoMapper(typeof(IDtoMapping), typeof(IViewModelMapping));
where IDtoMapping and IViewModelMapping are two marker interface (empty interface, used only to identify the assembly they are declared in) declared in the Business Layer and UI Layer, respectively.
I need to return a collection with nested optional collections from my WebAPI and convert it back to objects in my Web UI, however I'm getting the following error:
Cannot create and populate list type System.Linq.IQueryable`1[MyNamespace.MyClass].
I'm using Json.Net.
Here is a sample of my code:
public class ClassA
{
public Int64 Id { get; set; }
public String Description { get; set; }
public IEnumerable<ClassB> { get; set; }
}
public class ClassB
{
public Int64 Id { get; set; }
public String Description { get; set; }
}
I've saw some questions here in stackoverflow, but I don't have access to serialization options (it is handled internally by our library).
UPDATE
I've forgot to mention that ClassA is returned as an IQueryable in my Web API.
Changing the return type of my Web API method to IEnumerable instead of IQueryable solved the problem.
I have added computed fields(Active and CreditsLeft) directly into my CodeFirst entity class. Is it good idea to add computed field logic inside CF Entity class?
public class User : Entity
{
public User()
{
Id = Helper.GetRandomInt(9);
DateStamp = DateTime.UtcNow;
TimeZone = TimeZoneInfo.Utc.Id;
}
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int Id { get; set; }
[Required]
[MaxLength(50)]
public string Email { get; set; }
[Required]
[MaxLength(50)]
public string Password { get; set; }
[MaxLength(50)]
public string FirstName { get; set; }
[MaxLength(50)]
public string LastName { get; set; }
[Required]
public DateTime DateStamp { get; set; }
public virtual ICollection<Order> Orders { get; set; }
public virtual ICollection<Statistic> Statistics { get; set; }
public virtual ICollection<Notification> Notifications { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public bool Active
{
get
{
return Orders.Any(c => c.Active && (c.TransactionType == TransactionType.Order || c.TransactionType == TransactionType.Subscription));
}
}
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public int CreditsLeft
{
get
{
return Orders.Sum(p => p.Credits != null ? p.Credits.Value : 0);
}
}
}
Is it good idea to add computed field logic inside CF Entity class?
Sure, you can do this, but there are a few things you must take care of.
First, the attribute for a property that is computed by business logic is not [DatabaseGenerated(DatabaseGeneratedOption.Computed)], because this indicates that the value is computed in the database (as in a computed column). You should mark the property by the [NotMapped] attribute. This tells Entity Framework to ignore the property in database mapping.
Second, since both properties use Orders, you must make sure that the orders are loaded or can be lazy loaded when either property is accessed. So you may want to load Users with an Include statement (Include(user => user.Orders)). Or else you must ensure that the context is still alive when Active or CreditsLeft is accessed.
Third, you can't address the properties directly in an EF LINQ query, as in
db.Users.Select(u => u.Active);
because EF will throw an exception that it doesn't know Active. You can address the properties only on materialized user objects in memory.
document Structure:
class UserAccountInfo
{
public String Id { get; set; }
public AccountType AccountType { get; set; }Servicetax
public String MainAccountMobileNo { get; set; }
public UserStatus Status { get; set; }
public String EmailId { get; set; }
public String DisplayName { get; set; }
**public Object User { get; set; }**
}
object stores instance of any type that is mentioned in Account type. the type that is stored in the object can be found using Accountype for ex; if Accountype is customer then instance stored in the object will be AccountinfoCustomer and so on. So using that I've tried to query but getting the following exception from raven.
var Result = sess.Query<UserAccountInfo>().Where(x => x.AccountType == usertype && ((AccountInfoCustomer)x.User).Customerstatus == CustomerStatus.Pending);
{"Url: \"/indexes/dynamic/UserAccountInfos?query=AccountType%253ADistributor%2520AND%2520User).Customerstatus%253APending&start=0&pageSize=128&aggregation=None\"\r\n\r\nSystem.ArgumentException: The field ')_Customerstatus' is not indexed, cannot query on fields that are not indexed\r\n at Raven.Database.Indexing.Index.IndexQueryOperation.AssertQueryDoesNotContainFieldsThatAreNotIndexes()
This should work. Tested in current stable RavenDB 2.0.2230.
Tests here: https://gist.github.com/4692351
Are you on an older version?