I have a very basic EF setup that is throwing an odd error when trying to populate a navigation property by using .Include. Here are the entity Models:
public class LineGroup
{
public int ID { get; set; }
public string Name { get; set; }
public bool IsActive { get; set; }
public ICollection<LineGroupMember> LineGroupMembers { get; set; }
}
public class LineGroupMember
{
public int ID { get; set; }
public int Extension { get; set; }
public string Name { get; set; }
public int Permissions { get; set; }
public bool IsLoggedIn { get; set; }
public int LineGroupID { get; set; }
internal LineGroup LineGroup { get; set; }
}
I am using these through an injected DB context, and can query each just fine without using navigation properties. I can also query the LineGroups and include the LineGroupMembers property just fine, like so:
var LineGroups = _context.LineGroups.Include(l => l.LineGroupMembers).ToList();
This load all of the line groups into a list that has a correctly working "LineGroupMembers" collection for each Line Group. However, if I try
var lineGroupMembers = _context.LineGroupMembers.Include(m => m.LineGroup).ToList();
I get "NullReferenceException" with no helpful details. Any ideas why the navigation property will work one way and not the other? There are no null values in either database table...
Make your navigation property public
public LineGroup LineGroup { get; set; }
If it is internal it won't be picked up by default by EF. You could also add explicit fluent mapping to force EF to recognize it as well.
Related
I am using Entity Framework Core 5.0 and the following model:
So a Job has a MainFlow, and the mainflow can have 0 or more Subflows which in turn can have subflows (recursive)
The way this has been setup is that I have a Job entity which has a MainflowId property (and also navigation property)
The Flows have a ParentFlowId property, and a navigation property with a collection of SubFlows.
I also included a TreeId property on Job and Flow to easily identify a tree.
public class Job
{
public int Id { get; set; }
public DateTimeOffset Timestamp {get; set; }
public string JobName{ get; set; }
public int MainFlowId { get; set; }
public Guid TreeId { get; set; }
public virtual Flow MainFlow { get; set; }
}
public class Flow
{
public int Id { get;set; }
public string Name { get; set; }
public string DisplayName { get; set; }
public Guid TreeId { get; set; }
public int? ParentFlowId { get; set; }
public virtual Flow ParentFlow { get; set; }
public virtual ICollection<Flow> SubFlows { get; set; } = new List<Flow>();
}
What I am trying to achieve is to load a list of jobs (for example based upon the timestamp), but in a way that all the navigation properties become available (Job->Mainflow->Subflow->Subflow->...)
I was able to get this behavior by loading the jobs, and then loading the flows separately using the TreeId, however because of performance issues I am now using .AsNoTracking() and this does not seem to work anymore.
Is there a way to load the whole trees with their navigation properties while using .AsNoTracking?
Thanks for any insight!
Edit:
Here is the way it is working without the AsNoTracking()
(I simplified the code a bit)
private IQueryable<Job> GetAllJobs()
{
return DbContext.Set<Job>()
.Include(a=>a.MainFlow)
}
private IEnumerable<Flow> GetAllFlowsForTreeIds(IEnumerable<Guid> treeIds)
{
var result = from flow in DbContext.Set<Flow>()
.Include(a => a.ParentFlow)
.AsEnumerable()
join treeId in treeIds
on flow.TreeId equals treeId
select flow;
return result;
}
public IEnumerable GetJobTrees()
{
var allJobs = GetAllJobs().ToList();
var flows = GetAllFlowsForTreeIds(allJobs.Select(a=>a.TreeId)).ToList());
//by getting the flows, the navigation properties in alljobs become available
}
I need to update a child list from a parent adding records to it or updating one of its attributes. I receive the updated model from the Controller but when I try to replace the actual list with the new and save the changes to DB I get the error:
The instance of entity type 'WorkflowReferenciaExecucoes' cannot be tracked because another instance with the same key value for {'ReferenciaExecucoesId'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.
I don't have access to the dbContext directly because we are using the repository pattern. What I have tried to update the child in the service is:
private void Update(Workflow entity)
{
// entity is my updated model received by controller
// Getting the actual parent in the database
var workflow = GetById(entity.WorkflowId);
workflow.NomeWorkflow = entity.NomeWorkflow;
workflow.DescricaoWorkflow = entity.DescricaoWorkflow;
workflow.FgAtivo = entity.FgAtivo;
// Updating child list
workflow.WorkflowReferenciaExecucoes = entity.WorkflowReferenciaExecucoes;
// Trying to save the update gives error
_uow.WorkflowRepository.Update(entity);
}
My parent class is:
public class Workflow
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int WorkflowId { get; set; }
public int ProjetoId { get; set; }
public int WorkflowTipoId { get; set; }
public string NomeWorkflow { get; set; }
public string DescricaoWorkflow { get; set; }
public DateTime DataInclusao { get; set; }
public bool FgAtivo { get; set; }
public Projeto Projeto { get; set; }
public WorkflowTipo WorkflowTipo { get; set; }
public IEnumerable<WorkflowReferenciaExecucao> WorkflowReferenciaExecucoes { get; set; }
public IEnumerable<WorkflowCondicaoExecucao> WorkflowCondicaoExecucoes { get; set; }
}
And child class:
public class WorkflowReferenciaExecucao
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int ReferenciaExecucaoId { get; set; }
public int WorkflowId { get; set; }
public int? ExecucaoWorkflowId { get; set; }
public int ValorReferenciaExecucao { get; set; }
public bool FgProcessar { get; set; }
public bool FgAtivo { get; set; }
}
What do I have to do to update the actual list to the new one?
Thank you!
Could it be that the passed in entity has duplicates in the WorkflowReferenciaExecucoes property - meaning the same WorkflowReferenciaExecucao exists twice in that IEnumerable?
you can not update like that you have wrong relationship you class should be like that
public class WorkflowReferenciaExecucao
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int ReferenciaExecucaoId { get; set; }
public Workflow Workflow { get; set; }
public int? ExecucaoWorkflowId { get; set; }
public int ValorReferenciaExecucao { get; set; }
public bool FgProcessar { get; set; }
public bool Fugitive { get; set; }
}
WorkflowReferenciaExecucao is one and it has only one workflow so when you update Workflow then you have to update only workflow id in WorkflowReferenciaExecucao don't pass whole object just pass id to change it one to many relationship so on one side you update anything it don't relate to many relationship because it only point to id that it
I can reproduce your problem when there are multiple child records with the same ReferenciaExecucoesId in the update entity.
You can check if this is the case.
I've revisited my web site recently and had to upgrade from ASP.net MVC (DBF) core 2.0 to 2.1.
Since doing so I'm getting the following error...
SqlException: Invalid column name 'MovieTitleId'. Invalid column name 'MovieTitleId'.
Yet there is no such field 'MovieTitleId' in any part of my code or db.
The error occurs only when the site is accessing the 'many table' Scenes
(there is a one-to-many relationship set up in the db with FKs.. Movie > Scenes)
This is the Scene class..
public partial class Scene
{
[Key]
public int SceneId { get; set; }
[ForeignKey("TitleId")]
public int? TitleId { get; set; } // foreign key from Movie
[ForeignKey("LocationSiteId")]
public int? LocationSiteId { get; set; }
[ForeignKey("LocationAliasId")]
public int? LocationAliasId { get; set; }
public string Notes { get; set; }
public int? SceneOrder { get; set; }
public string TitleList { get; set; }
public LocationAlias LocationAlias { get; set; }
public LocationSite LocationSite { get; set; }
public Movie Movie { get; set; }
}
And this is the Movie class which on the 'one side' and call Scenes on a typical 'Master/Detail' type web page...
public partial class Movie
{
public Movie()
{
Scenes = new HashSet<Scene>();
}
[Key]
public int TitleId { get; set; }
[Required]
public string Title { get; set; }
[DisplayName("Title")]
public string ParsedTitle { get; set; }
[DisplayName("Year")]
public int? TitleYear { get; set; }
public string ImdbUrl { get; set; }
public string Summary { get; set; }
public bool? ExcludeTitle { get; set; }
public bool? Widescreen { get; set; }
[DisplayName("Title")]
public override string ToString()
{
return Title + " (" + TitleYear + ")";
}
public ICollection<Scene> Scenes { get; set; }
}
The error occurs in the MoviesController.cs...
Movie movie = _context.Movies.Find(id);
ViewBag.Scenes = _context.Scenes
.Where(s => s.TitleId == id)
.Include(s => s.LocationSite)
.Include(s => s.LocationSite.LocationPlace)
.OrderBy(s => s.SceneOrder).ToList();
Everything used to work fine until i upgraded to core 2.1.
I can't even recall there ever being a field called 'MovietitleId' which is actually 'TitleId'.
Is the error msg concatenating the model 'Movie' and column 'TitleId' somehow?
Try adding virtual keyword for your foreign key. Also the ForeignKey Data Annotation should be on that property where you have declared your virtual property just like below. So it should be something like this:
Scene.cs
public int TitleId { get; set; }
[ForeignKey("TitleId")
public virtual Movie Movie { get; set; }
Why virtual?
If you declare your property virtual your virtual property (by default) won't be loaded right away when querying the main object. It will be retrieved from the database ONLY if you try to access it. This is called lazy loading.
If you want to know why to use virtual in detail, you may visit this link: Why are foreign keys in EF Code First marked as virtual?
Hope this helps.
After trying to execute the following query:
List<CourseLesson> courseLessons = (from cl in context.CourseLessons
.Include(x => x.CourseLessonTestQuestions)
select cl).ToList();
I get the the error Invalid column name 'CourseLesson_Id'.
My models and DataContext looks like this(this is from a test project I've created to repreduce the problem)
public class CourseLesson
{
public int Id { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public ICollection<CourseLessonTestQuestion> CourseLessonTestQuestions { get; set; }
}
public class CourseLessonTestQuestion
{
public int Id { get; set; }
public int CourseLessonId { get; set; }
[ForeignKey(nameof(CourseLessonId))]
public CourseLesson CourseLesson { get; set; }
public int? ReturnCourseLessonId { get; set; }
[ForeignKey(nameof(ReturnCourseLessonId))]
public CourseLesson ReturnCourseLesson { get; set; }
}
I have 2 foreign keys that point to the same table and I'm assuming EF is trying to create or map something that doesn't really exist.
After reading for a while I've found a way to fix my problem in (this answer) with the following code:
modelBuilder.Entity<CourseLessonTestQuestion>()
.HasOptional(cltq => cltq.ReturnCourseLesson)
.WithMany(x => x.CourseLessonTestQuestions);
What really bugs me about this situation is why everything works when I use the Fluent API, but it doesn't work with the ForeignKey attribute? This looks like something that could lead to future problems and I want to know what is really happening.
And the real question is there a solution for fixing this problem without the Fluent API? Like using attributes or some other convention?
I'm using Entity Framework 6.1.3
Solution without Fluent API, but with the help of InversePropertyAttribute, whose constructor's argument is the name of corresponding CourseLessonTestQuestion's property:
public class CourseLesson
{
public int Id { get; set; }
public string Title { get; set; }
public string Content { get; set; }
[InverseProperty("CourseLesson")]
public ICollection<CourseLessonTestQuestion> CourseLessonTestQuestions { get; set; }
[InverseProperty("ReturnCourseLesson")]
public ICollection<CourseLessonTestQuestion> ReturnCourseLessons { get; set; }
}
I'm missing something when using the data annotations.
This is my first class
[Table("PriceFeed")]
public class PriceFeed : History
{
public PriceFeed()
{
this.Votes = new List<PriceVote>();
this.History = new List<PriceFeed__History>();
}
[Key]
public long Id { get; set; }
[ForeignKey("Store")]
public long Store_Id { get; set; }
[ForeignKey("Item")]
public long Item_Id { get; set; }
[Required]
public decimal Price { get; set; }
public Store Store { get; set; }
public Item Item { get; set; }
public virtual ICollection<PriceFeed__History> History { get; set; }
}
And this is my second class
[Table("PriceFeed__History")]
public class PriceFeed__History : History
{
[Key]
public long Id { get; set; }
[ForeignKey("PriceFeed")]
public long PriceFeed_Id { get; set; }
[Required]
public decimal Price { get; set; }
public virtual PriceFeed PriceFeed { get; set; }
}
When I run the add-migration, it creates the database correctly but when I try to access PriceFeed.History it gives me an error
{"Message":"An error has occurred.","ExceptionMessage":"A specified Include path is not valid. The EntityType 'Verdinhas.Web.Contexts.PriceFeed' does not declare a navigation property with the name 'PriceFeed__History'."
I always worked with API Fluent and typed by myself the code like
.Entity<Student>()
.HasRequired<Standard>(s => s.Standard)
.WithMany(s => s.Students)
.HasForeignKey(s => s.StdId);
But now I'm using the data annotations and when I generate the migration, it does not create the "withmany" like the above.
What am I doing wrong?
The issue has nothing to do with Data Annotations which seems to be correct in your model.
As mentioned in the comments, the exception is caused by a code that tries to use Include method with string "'PriceFeed__History" - you seem to think that you should specify the related entity types, but in fact you need to specify the navigation property names, which in your case is "History".