I am trying to add a new record in an MVC controller method using Entity framework.
When i just used "InsertOrUpdate" the audittype got duplicated. Based on the answer from Entity Framework adding record with a related object i hoped to fix it pretty qiock. This is the code I have right now:
Controller:
if (ModelState.IsValid)
{
Audit newAudit = Factory.GetNew();
newAudit.Name = model.Name;
newAudit.Deadline = model.Deadline;
newAudit.AuditType = auditTypeRepository.Find(model.SelectedAuditTypeId);
Repository.InsertOrUpdate(newAudit);
Repository.Save();
return RedirectToAction(MVC.Audits.Details(newAudit.Id));
}
Repository:
public override void InsertOrUpdate(Qdsa.WebApplications.AuditMaster.Data.Audit model)
{
if (model.Id == default(int))
{
// New entity
context.Audits.Add(model);
}
else
{
// Existing entity
model.ModifiedOn = DateTime.Now;
context.Entry(model).State = EntityState.Modified;
}
//If I leave out the code below the AuditType will be duplicated
if (model.AuditType != null)
{
context.Entry<AuditType>(model.AuditType).State = EntityState.Unchanged;
}
}
public virtual void Save()
{
context.SaveChanges();
}
So i thought I fixed the problem. However, AuditType has Child objects too. And now these childobjects get duplicated.
What is the right way to add entities with child objects which already exists?
Because the AuditType is required I can't save it without first and then update it. any suggestions?
UPDATE:
Both the AuditRepostory and the AuditTypeRepository inherit from BaseRepository which has the context as:
protected DBContext context = new DBContext ();
public virtual T Find(int id)
{
return All.SingleOrDefault(s => s.Id == id);
}
I can imagine two reasons for the problem:
Either auditTypeRepository.Find performs a no tracking query (with .AsNoTracking())
Or you are using a context instance per repository, so that Repository and auditTypeRepository are working with two different contexts which will indeed result in a duplication of the AuditType because you don't attach it to the the context that corresponds with Repository (except in the line with your comment).
If the latter is the case you should rethink your design and inject a single context instance into all repositories instead of creating it inside of the repositories.
I think the problem is from here:
newAudit.AuditType = auditTypeRepository.Find(model.SelectedAuditTypeId);
Change that like this:
newAudit.AuditTypeId = model.SelectedAuditTypeId;
Related
I ran into an issue where I was intermittently receiving an error:
An entity object cannot be referenced by multiple instances of IEntityChangeTracker
whenever trying to attach an entity to the DbContext.
UPDATE: Original post is below and is TL;DR. So here is a simplified version with more testing.
First I get the Documents collection. There are 2 items returned in this query.
using (UnitOfWork uow = new UnitOfWork())
{
// uncomment below line resolves all errors
// uow.Context.Configuration.ProxyCreationEnabled = false;
// returns 2 documents in the collection
documents = uow.DocumentRepository.GetDocumentByBatchEagerly(skip, take).ToList();
}
Scenario 1:
using (UnitOfWork uow2 = new UnitOfWork())
{
// This errors ONLY if the original `uow` context is not disposed.
uow2.DocumentRepository.Update(documents[0]);
}
This scenario works as expected. I can force the IEntityChangeTracker error by NOT disposing the original uow context.
Scenario 2:
Iterate through the 2 items in the documents collection.
foreach (Document document in documents)
{
_ = Task.Run(() =>
{
using (UnitOfWork uow3 = new UnitOfWork())
{
uow3.DocumentRepository.Update(document);
});
}
}
Both items fail to attach to the DbSet with the IEntityChangeTracker error. Sometimes one succeeds and only one fails. I assume this might be to do with the exact timings of the Task Scheduler. But even if they are attaching concurrently, they are different document entities. So they shouldn't be being tracked by any other context. Why am I getting the error?
If I uncomment ProxyCreationEnabled = false on the original uow context, this scenario works! So how are they still being tracked even thought the context was disposed? Why is it a problem that they are DynamicProxies, even though they are not attached to or tracked by any context.
ORIGINAL POST:
I have an entity object called Document, and it's related entity which is a collection of DocumentVersions.
In the code below, the document object and all related entities including DocumentVersions have already been eagerly loaded before being passed to this method - which I will demonstrate after.
public async Task PutNewVersions(Document document)
{
// get versions
List<DocumentVersion> versions = document.DocumentVersions.ToList();
for (int i = 0; i < versions.Count; i++)
{
UnitOfWork uow = new UnitOfWork();
try
{
versions[i].Attempt++;
//... make some API call that succeeds
versions[i].ContentUploaded = true;
versions[i].Result = 1;
}
finally
{
uow.DocumentVersionRepository.Update(versions[i]); // error hit in this method
uow.Save();
}
}
}
The Update method just attaches the entity and changes the state. It is part of a GenericRepository class that all my Entity Repositories inherit from:
public virtual void Update(TEntity entityToUpdate)
{
dbSet.Attach(entityToUpdate); // error is hit here
context.Entry(entityToUpdate).State = EntityState.Modified;
}
The document entity, and all related entities are loaded eagerly using a method in the Document entity repository:
public class DocumentRepository : GenericRepository<Document>
{
public DocumentRepository(MyEntities context) : base(context)
{
this.context = context;
}
public IEnumerable<Document> GetDocumentByBatchEagerly(int skip, int take)
{
return (from document in context.Documents
.Include(...)
.Include(...)
.Include(...)
.Include(...)
.Include(d => d.DocumentVersions)
.AsNoTracking()
orderby document.DocumentKey descending
select document).Skip(skip).Take(take);
}
}
The method description for .AsNoTracking() says that "the entities returned will not be cached in the DbContext". Great!
Then why does the .Attach() method above think that this DocumentVersion entity is already referenced in another IEntityChangeTracker? I am assuming this means it is referenced in another DbContext, i.e: the one calling GetDocumentByBatchEagerly(). And why does this issue only present intermittently? It seems that it happens less often when I am stepping through the code.
I resolved this by adding the following line to the above DocumentRepository constructor:
this.context.Configuration.ProxyCreationEnabled = false;
I just don't understand why this appears to resolve the issue.
It also means if I ever want to use the DocumentRepository for something else and want to leverage change tracking and lazy loading, I can't. There doesn't seem to be a 'per query' option to turn off dynamic proxies like there is with 'as no tracking'.
For completeness, here is how the 'GetDocumentsByBatchEagerly' method is being used, to demonstrate that it uses it's own instance of UnitOfWork:
public class MigrationHandler
{
UnitOfWork uow = new UnitOfWork();
public async Task FeedPipelineAsync()
{
bool moreResults = true;
do
{
// documents retrieved with AsNoTracking()
List<Document> documents = uow.DocumentRepository.GetDocumentByBatchEagerly(skip, take).ToList();
if (documents.Count == 0) moreResults = false;
skip += take;
// push each record into TPL Dataflow pipeline
foreach (Document document in documents)
{
// Entry point for the data flow pipeline which links to
// a block that calls PutNewVersions()
await dataFlowPipeline.DocumentCreationTransformBlock.SendAsync(document);
}
} while (moreResults);
dataFlowPipeline.DocumentCreationTransformBlock.Complete();
// await completion of each block at the end of the pipeline
await Task.WhenAll(
dataFlowPipeline.FileDocumentsActionBlock.Completion,
dataFlowPipeline.PutVersionActionBlock.Completion);
}
}
I am trying to move a record from one table into another matching (almost) table using EF5, MVC, and Automapper.
This code is what I am using:
In My Global Application_Start
//Create Map and manually map StatusCode to Status
Mapper.CreateMap<InstitutionStaging, InstitutionStaging_Archive>()
.ForMember(dest => dest.Status,o =>o.MapFrom(src=>src.StatusCode));
In my Controller
private MyContext db = new MyContext();
Public ActionResult ArchiveMe(int id = 0){
var institutionstaging = db.InstitutionStagings.Find(id);
if (institutionstaging == null)
{
return HttpNotFound();
}
if (ModelState.IsValid)
{
var institutionArchive = Mapper.Map<InstitutionStaging, InstitutionStaging_Archive>(institutionstaging);
//Set Archive date to now.
institutionArchive.ArchiveDate = DateTime.Now;
//Error happens on the next line
db.InstitutionStaging_Archives.Add(institutionArchive);
db.InstitutionStagings.Remove(institutionstaging);
db.Entry(institutionArchive).State = EntityState.Added;
//Commit the changes
var result = db.SaveChanges();
}
}
When it hits the line marked "Error happens here==>" I get the following error message.
{"The entity type InstitutionStaging_Archive is not part of the model for the current context."}
The MyContext contains DbSets for both InstitutionStaging and InstitutionStaging_Archive.
Any idea what is happening?
TIA
J
This error isn't typically a problem with AutoMapper, but rather a problem with your Entity Framework model setup.
It can be because you are using the wrong connection string, or it can be because you don't have the model mapped correctly.
Since we don't know what your model is, what your database looks like, or how your mappings are.. can't help much beyond that.
To prove it to yourself, just comment out the automapper stuff and do it by hand, and I'm pretty sure you'll get the same error.
I have this in my mvc ActionResult
[HttpPost]
public ActionResult _ChangeDetails( [Bind(Prefix="ContactDetails")] userDetail UserDetail )
{
MemberChangeDetailsFormViewModel fvm = new MemberChangeDetailsFormViewModel();
if (ModelState.IsValid)
{
//save
UserDetailRepository repository = new UserDetailRepository();
repository.Save(UserDetail);
return RedirectToAction("Index", "Member");
}
fvm.ContactDetails = UserDetail;
return View(fvm);
}
Then in my repository I have;
if (userDetail.id != Guid.Empty)
{
userDetail orig = dc.userDetails.Where(x => x.id == userDetail.id).Single();
dc.userDetails.Attach(userDetail, orig);
dc.Refresh(System.Data.Linq.RefreshMode.KeepCurrentValues, userDetail);
dc.SubmitChanges();
}
However the "attach" is generating an error; Cannot add an entity with a key that is already in use.
I understand that it's caused because L2S already has the object attached. I have tried doing this with and without the orig object but get the same message.
What would be the best practice to update the data in the table from the model?
Linq-to-SQL can't deal with two objects with the same key in the same data context. Some options:
Option 1: Use two different data contexts:
public void Update(UserDetail modifiedUser)
{
using (UserDetailDataContext dc1 = new UserDetailDataContext())
using (UserDetailDataContext dc2 = new UserDetailDataContext())
{
UserDetail originalUser = dc1.UserDetails.Single(u => u.id == modifiedUser.id);
dc2.UserDetails.Attach(modifiedUser, originalUser);
dc2.SubmitChanges();
}
}
Option 2: Don't pull the original object; annotate the new object as an update:
public void Update(UserDetail modifiedUser)
{
using (UserDetailDataContext dc = new UserDetailDataContext())
{
dc.UserDetails.Attach(modifiedUser);
dc.Refresh(RefreshMode.KeepCurrentValues, modifiedUser);
dc.SubmitChanges();
}
}
There's more discussion in this question, and Rick Strahl has a blog entry that covers a versioning-based strategy, if you're willing to modify the table schema to add a timestamp.
I've got some MVC code that serializes an EF 3.5 object into an anonymous type for return as a JSON result to an AJAX call on my page. The hurdle I have is that when I send the object back to the server via JSON, (and let the ModelBinder deserialize it for me into my EF type), I have to update it in my Entity Framework context manually. Or at least that's what I'm doing now. It has no EntityKey, so attaching it fails. I end up having to look up the old object and update it property by property. Any ideas around this? Is the solution to pass the EntityKey around with my object?
Here's what I have:
public void Update(Album album)
{
using (var db = new BandSitesMasterEntities())
{
var albumToUpdate = db.Album.First(x => x.ID == album.ID);
albumToUpdate.AlbumTitle = album.AlbumTitle;
albumToUpdate.Description = album.Description;
albumToUpdate.ReleaseYear = album.ReleaseYear;
albumToUpdate.ImageURL = album.ImageURL;
albumToUpdate.OtherURL = album.OtherURL;
db.SaveChanges();
}
}
And here's what I'd like to do, or something similar:
public void Update(Album album)
{
using (var db = new BandSitesMasterEntities())
{
db.Attach(album)
db.SaveChanges();
}
}
or you could use AutoMapper to map those fields for you, so you'd just add one extra line to your example.
Why not just use the UpdateModel or TryUpdateModel controller methods instead? It works really well with EF and you can even explicitly set the included property list.
The id parameter will auto-map via the MVC framework to the hidden field on your form specifying the id.
public void Update(int id, FormCollection collection)
{
using (var db = new BandSitesMasterEntities())
{
var albumToUpdate = db.Album.First(x => x.ID == id);
//use UpdateModel to update object, or even TryUpdateModel
UpdateModel(albumToUpdate, new string[] { "AlbumTitle", "Description", "ReleaseYear", "ImageURL", "OtherURL" });
db.SaveChanges();
}
}
This became much easier for us in EF 4.0. This is what we did in EF 3.5:
public static void AttachAsModified(this ObjectContext objectContext, string setName, object entity,
IEnumerable<String> modifiedFields)
{
objectContext.AttachTo(setName, entity);
ObjectStateEntry stateEntry = objectContext.ObjectStateManager.GetObjectStateEntry(entity);
foreach (String field in modifiedFields)
{
stateEntry.SetModifiedProperty(field);
}
}
And then:
using (var db = new BandSitesMasterEntities())
{
db.AttachAsModified("Album", album, new string[] { "AlbumTitle", "Description", "ReleaseYear", "ImageURL", "OtherURL" })
db.SaveChanges();
}
It becomes more complicated if you have foreign key constraints, but it looks like you don't.
There is no way around the entity key issue. You either have to add it to your anonymous type or I would recommend you port your code to using data services.
http://www.hanselman.com/blog/jQueryToShipWithASPNETMVCAndVisualStudio.aspx
which would allow you to do all of the db manipulation on the client side.
http://msdn.microsoft.com/en-us/data/bb931106.aspx
Did you try something like:
object original;
var key = contexte..CreateEntityKey("EntitySet", modified);
if(contexte.TryGetObjectByKey(key, out original))
{
var originalEntity = (YourEntityType)original;
// You have to mannualy set your entityKey
originalEntity.YourEntityReference.EntityKey = new EntityKey("Entities.EntitySet", "Id", modified.YourEntity.Id);
contexte.ApplyPropertyChanges("EntitySet", modified);
}
contexte.SaveChanges();
Assuming that your EntityReference are set by dropDown, you'll still have the Id
In your Album entity's partial class you may define a CopyFrom function and call it from your Update function
partial class Album
{
public void CopyFrom(Album album)
{
//individual field copying here
}
}
public void Update(Album album)
{
...
albumToUpdate.CopyFrom(album);
...
}
When I run following code:
public ActionResult Complete()
{
try
{
VeriTabanDataContext db = new VeriTabanDataContext();
db.Persons.InsertOnSubmit(_person);
db.SubmitChanges();
return View(_person);
}
catch (Exception ex)
{
return RedirectToAction("Error", ex);
}
}
I'm getting following Exception, on SubmitChanges();
"An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported."
Here "_person" object is taken from Session and is a good standing. Note: _person is a result of multistep wizard and this is the place where I add new Person object to the DB.
My Person table has 9 relations and it's not ok for me to add version column for each of them as is suggested by some geeks around
I've investigated this problem a lot and spend 2 days on it and still couldn't solve it. Some of the workarounds that other suggest don't solve my problem, and others seem to be just dirty workaround. Do you experts have a good solution for this problem, considering that Person class has many relations and also it isn't ok to add a column to the tables.
I also want to note that I've tried to use 'db.Persons.Attach(_person) ' and setting db.DeferredLoadingEnabled = false; THis time I'm not getting any Exception but data is NOT saved to DB
I create a class called applicationController which derives from Controller. Then i make all of my controller classes derive from this. The applicationController class has a constrcutor which creates a new instance of my repository (or datacontext in your instance) which is used throughout the application:
public class ApplicationController : Controller
{
private VeriTabanDataContext _datacontext;
public ApplicationController() : this(new VeriTabanDataContext())
{
}
public ApplicationController(VeriTabanDataContext datacontext)
{
_datacontext = datacontext;
}
Public VeriTabanDataContext DataContext
{
get { return _datacontext; }
}
}
Then you can use this in all of your controllers
public class MyController : ApplicationController
{
public ActionResult Complete()
{
DataContext.Persons.InsertOnSubmit(_person);
DataContext.SubmitChanges();
return View(_person);
}
}
Not on my PC with VS installed at the moment so not tested this code....
Hope this resolves the issue -Mark
Can you do the following:
var foundPerson = db.Person.FirstOrDefault( p => p.Id == _person.Id);
if(foundPerson == null)
{
db.InsertOnSubmit(_person);
}else{
Mapper.Map(_person,foundPerson);
}
db.SubmitChanges();
return View(_person);
Where I have used AutoMapper to map from one entity to another. To do this add the reference to AutoMapper to your project and in your start up code for the application you will need to configure your mappings, for the above to work you would need:
Mapper.CreateMap<Person, Person>().ForMember(src => src.Id, opt => opt.Ignore());