I use database first. In the auto-generated EF5 code:
Account has ClientID(FK)
Client has AddressID(FK)
Address has public List<EFClient> Clients { get; set; } (i did not specify this in DB but ef5 auto generated it)
When I serialize Address object, it throws exception "there is a circular reference" because the client collection in the address also cotains same address again
What can I do in this situation?
How can I not let EF5 auto-generate that Clients collection?
Thanks in advance!
I don't think you actually want to stop EF from auto-generating this navigation property, as it will affect lots of places. What you can do is simply remove the property that it generated from the model, which will remove the property from the class.
Related
I have a table Test with a foreign key to itself. In metadata class I have
[Include]
Test Test2 { get; set; }
In a service class:
return this.ObjectContext.Test.Include("Test2")
I checked that data loaded correctly from database. But on a client side I see that no parent has been loaded.
I use a DomainDataSource to load data (Silverlight 4.0).
Someone else experienced this strange behavior?
Ok, my mistake. The answer is to use [Include] attribute as always, but make sure that all participating properties are public in your metadata class.
I'm using XmlSerializer. I've had no problems with it until now. I updated Silverlight from 4 to 5 and at the same time also updated the WCF RIA Services from v1 SP1 to v1 SP2. Now the following line gives me an error.
XmlSerializer s = new XmlSerializer(typeof(MyCustomObject));
The error is:
System.InvalidOperationException: System.ServiceModel.DomainServices.Client.EntityConflict cannot be serialized because it does not have a parameterless constructor.
The object I'm using (MyCustomObject in the sample) has not changed in any way so I'm starting to think it's either SL5 or the new RIA Services that is breaking my code. I didn't find any breaking changes document or mentions that this could happen. I don't know why it has a problem with EntityConflict since I'm not using any entities within my object.
Has anyone seen an error like this and/or know how to solve it?
UPDATE!
The final property that the error message says before EntityConflict is an Entity. I think that makes a difference but it has been working before. I'd also like to know why the serializer already tries to serialize the object in the constructor?
public static XmlSerializer GetEntityXmlSerializer<TEntity>()
where TEntity : Entity
{
XmlAttributes ignoreAttribute = new XmlAttributes()
{
XmlIgnore = true,
};
// use base class of Entity,
// if you use type of implementation
// you will get the error.
Type entityType = typeof(Entity);
var xmlAttributeOverrides = new XmlAttributeOverrides();
xmlAttributeOverrides.Add(entityType, "EntityConflict", ignoreAttribute);
xmlAttributeOverrides.Add(entityType, "EntityState", ignoreAttribute);
return new XmlSerializer(typeof(TEntity), xmlAttributeOverrides);
}
I am not sure why this would be happening, RIA Services entities are not XmlSerializable objects and the entities themselves are not decorated with the [Serializable] attribute. Have you added partial classes on the client side which decorate the entities with [Serializable] or modified the code generation in some way?
I got around this problem by using intermediary serializable POCO objects which were copies of my custom objects (which were inherited from Entity). The POCO objects did not inherit from Entity. I just updated their values from the original Entity objects. They then serialized quite nicely. Of course, when you de-serialize you need to update your Entity objects from the POCO objects.
I am working on a silverlight application and I am using RIA data services and nHibernate.
Currently, I have an entity with a one to many relationship to another entity.
public class Employer {
[Key]
public virtual int Id { get; set; }
public virtual string Name { get; set; }
}
public class Person {
[Key]
public virtual int Id { get; set; }
public virtual string Name { get; set; }
[Include]
[Association("PersonCurrentEmployer", "CurrentEmployerId", "Id", IsForeignKey = true)]
public virtual Employer CurrentEmployer { get; set; }
public virtual int? CurrentEmployerId { get; set; }
}
The property CurrentEmployerId is set for no insert and no update in the mappings.
On the Silverlight side, I set the CurrentEmployer property of the person to an existing employer on the client side submit the changes.
personEntity.CurrentEmployer = megaEmployer;
dataContext.SubmitChanges();
On the server side, the person entity's CurrentEmployerId is set to megaEmployer.Id but the CurrentEmployer is null. Because I am using the CurrentEmployer property and not the CurrentEmployerId to save the relationship, the relationship isn't changed.
Is there a way to force RIA to send the CurrentEmployer object with the save or do I have to use the CurrentEmployerId on the server side to load the employer and set it to the CurrentEmployer?
The reason you're not seeing your CurrentEmployer on the client side is because you don't have your association setup correctly.
RIA services doesn't work with references in the usual way so referencing your Employer on the client side doesnt work. RIA services works with entity sets and creates the "references" based on the association attributes. Your employer needs a property with an association back to the Person as follows.
public class Employer
{
private Person person;
[Key]
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual int PersonID { get; set; }
[Include]
[Association("PersonCurrentEmployer", "PersonID", "Id", IsForeignKey = false)]
public virtual Person Person {
get
{
return this.person;
}
set
{
this.person = value;
if (value != null)
{
this.PersonID = value.Id;
}
}
}
}
Is there a way to force RIA to send the CurrentEmployer object with the save or do I have to use the CurrentEmployerId on the server side to load the employer and set it to the CurrentEmployer?
I'm running into this problem as well. Basically, you either have to use the [Composition] attribute (which I wouldnt' recommend), or load the entity from the database, server-side. Composition muddies up the client data model and doesn't take care of all cases you need to worry about. (there is a lot more on Composition in the RIA forums.silverlight.net)
[UPDATE] Once you implement 2nd level cache, the worry of reading supporting entities from the database mostly goes away, as they will be loaded from cache. Also, if you only need a proxy for NHibernate to not complain, then look into Get/Load (can never remember which) .. which will return an NH proxy and will result in a single-column-and-entity select from the database. (If you try to access another property of the proxy, NH will select the rest. you can find more on this on Ayende's blog..)[/UPDATE]
The biggest problem I'm having is getting NHib to actually save and load the relationship. (I'm also using Fluent). The response from the responsible parties has so far been "waah, you can't do that. it looks like RIA wasn't developed with NHib in mind" .. which is a crap answer, IMHO. Instead of helping me figure out how to map it, they're telling me i'm doing it wrong for having a ForeignKey in my entity (NHib shouldn't care that i have my FK in my entity) ...
I want to share what I did to make this work, because 'official' support for this scenario was ... let's just say unhelpful at best, and downright rude at worst.
Incidentally, you had the same idea I had: making the Foreign Key not insert/update. BUT, I've also made it Generated.Always(). this way it will always read the value back.
Additionally, I override DomainService.Submit() and DomainService.ExecuteChangeSet(). I start an NHibernate Transaction in the Submit (though I'm not yet sure this does what I expect it does).
Instead of putting my save logic in the InsertSomeEntity() or UpdateSomeEntity() methods, I'm doing it all inside ExecuteChangeSet. this is because of NHibernate, and its NEED to have the entity graph fully-bi-directional and hydrated out prior to performing actions in NHibernate. This includes loading of entities from the database or session when a child item comes across the wire from RIA services. (I started down the path of writing methods to get the various other pieces of the graph as those specialized methods needed them, but I found it easier to do it all in a single method. Moreover, I was running into the problem of RIA wanting me to perform the insert/updates against the child objects first, which for new items is a problem.)
I want to make a comment about the composition attribute. I still stand by my previous comment about not recommending it for standard child entity collections, HOWEVER, it works GREAT for supporting NHibernate Components, because otherwise RIA will never send back the parent instance (of the composition), which is required for NHibernate to work right.
I didn't provide any code here because i would have to do some heavy redacting, but it's not a problem for me to do if you would like to see it.
RIA Services is returning a list of Entities that won't allow me to add new items. Here are what I believe to be the pertinent details:
I'm using the released versions of Silverlight 4 and RIA Services 1.0 from mid-April of 2010.
I have a DomainService with a query method that returns List<ParentObject>.
ParentObject includes a property called "Children" that is defined as List<ChildObject>.
In the DomainService I have defined CRUD methods for ParentObject with appropriate attributes for the Query, Delete, Insert, and Update functions.
The ParentObject class has an Id property marked with the [Key] attribute. It also has the "Children" property marked with the attributes [Include], [Composition], and [Association("Parent_Child", "Id",
"ParentId")].
The ChildObject class has an Id marked with the [Key] attribute as well as a foreign key, "ParentId", that contains the Id of the parent.
On the client side, data is successfully returned and I assign the results of the query to a PagedCollectionView like this:
_pagedCollectionView = new PagedCollectionView(loadOperation.Entities);
When I try to add a new ParentObject to the PagedCollectionView like this:
ParentObject newParentObject = (ParentObject)_pagedCollectionView.AddNew();
I get the following error:
" 'Add New' is not allowed for this view."
On further investigation, I found that _pagedCollectionView.CanAddNew is "false" and cannot be changed because the property is read-only.
I need to be able to add and edit ParentObjects (with their related children, of course) to the PagedCollectionView. What do I need to do?
I was just playing around with a solution yesterday and feel pretty good about how it works. The reason you can't add is the source collection (op.Entities) is read-only. However, even if you could add to the collection, you'd still want to be adding to the EntitySet as well. I created a intermediate collection that takes care of both these things for me.
public class EntityList<T> : ObservableCollection<T> where T : Entity
{
private EntitySet<T> _entitySet;
public EntityList(IEnumerable<T> source, EntitySet<T> entitySet)
: base(source)
{
if (entitySet == null)
{
throw new ArgumentNullException("entitySet");
}
this._entitySet = entitySet;
}
protected override void InsertItem(int index, T item)
{
base.InsertItem(index, item);
if (!this._entitySet.Contains(item))
{
this._entitySet.Add(item);
}
}
protected override void RemoveItem(int index)
{
T item = this[index];
base.RemoveItem(index);
if (this._entitySet.Contains(item))
{
this._entitySet.Remove(item);
}
}
}
Then, I use it in code like this.
dataGrid.ItemsSource = new EntityList<Entity1>(op.Entities, context.Entity1s);
The only caveat is this collection does not actively update off the EntitySet. If you were binding to op.Entities, though, I assume that's what you'd expect.
[Edit]
A second caveat is this type is designed for binding. For full use of the available List operation (Clear, etc), you'd need to override a few of the other methods to write-though as well.
I'm planning to put together a post that explains this a little more in-depth, but for now, I hope this is enough.
Kyle
Here's a workaround which I am using:
Instead of using the AddNew, on your DomainContext you can retrieve an EntitySet<T> by saying Context.EntityNamePlural (ie: Context.Users = EntitySet<User> )
You can add a new entity to that EntitySet by calling Add() and then Context.SubmitChanges() to send it to the DB. To reflect the changes on the client you will need to Reload (Context.Load())
I just made this work about 15mins ago after having no luck with the PCV so I am sure it could be made to work better, but hopefully this will get you moving forward.
For my particular situation, I believe the best fit is this (Your Mileage May Vary):
Use a PagedCollectionView (PCV) as a wrapper around the context.EntityNamePlural (in my case, context.ParentObjects) which is an EntitySet. (Using loadOperation.Entities doesn't work for me because it is always read-only.)
_pagedCollectionView = new PagedCollectionView(context.ParentObjects);
Then bind to the PCV, but perform add/delete directly against the context.EntityNamePlural EntitySet. The PCV automatically syncs to the changes done to the underlying EntitySet so this approach means I don't need to worry about sync issues.
context.ParentObjects.Add();
(The reason for performing add/delete directly against the EntitySet instead of using the PCV is that PCV's implementation of IEditableCollectionView is incompatible with EntitySet causing IEditableCollectionView.CanAddNew to be "false" even though the underlying EntitySet supports this function.)
I think Kyle McClellan's approach (see his answer) may be preferred by some because it encapsulates the changes to the EntitySet, but I found that for my purposes it was unneccessary to add the ObservableCollection wrapper around loadOperation.Entities.
Many thanks to to Dallas Kinzel for his tips along the way!
I constructed my Entity Model. One of my business objects,let's call it Store has a spatial data type. Very quickly I figured out that spatial fields aren't mapped via EF4. However I struggled my way out, by editing the xml declarations defining a query like the following:
<EntitySet Name="Stores" EntityType="Eltrun.OnShelfAuditModel.Store.Stores">
<DefiningQuery>
SELECT [rowId], [storeName], [location].STAsText() as location FROM Stores
</DefiningQuery>
</EntitySet>
At this point I decided to customize my Store entity via a partial class like this, just to make the conversion and still keep the SQLGeography data stored, returning just a double[] at client (as I cannot return neither SqlGeography, neither Location (Bing datatype).
public partial class Store
{
public double[] StoreLocation
{
get
{
SqlGeography geoLocation = SqlGeography.
STPointFromText(new SqlChars(this.location.ToCharArray()), 4326);
return new double[]{
(double)geoLocation.Lat,
(double)geoLocation.Long};
}
}
}
How can I make aware the Store data type of my little customization, at client project?
Thank you!
Just add a setter to your property, and the RIA Services code generator and serializer should create the equivalent property on the client's version of the Store class.
Hope that helps...