I'm following this post here
his code looks like so
from p in ctx.Persons
where p.ID == personId
select new PersonInfo
{
Name = p.FirstName + " " + p.LastName,
BornIn = p.BornInCity.Name,
LivesIn = p.LivesInCity.Name,
Gender = p.Sex.Name,
CarsOwnedCount = p.Cars.Count(),
}
Now when he is using p.LivesInCity.Name ( My Assumption is that he has 2 different ViewModels Classes and 1 of them has an IEnumerable or some sort of collection of City names?)
Question
How can he access p.LivesInCity.Name but when i Try p.Countys.[CountyColectionForSections].[SectionProperty] I get See Image Below
here is how i setup my ViewModels
Table 1
public string Client { get; set; }
public virtual ICollection<dbProspect> Prospects { get; set; }
Table 2
public int Prospect { get; set; }
public virtual ICollection<dbCounty> Countys { get; set; }
public virtual ICollection<UserProfiles> UserProfiles { get; set; }
Table 3...
Table 3 Would have a collection of another table, and table 4 would have another colection and so on Basically a Table Hierarchy about 15 deep.
here is how i try and access them
var x = from c in db.Client
select new ViewModelExcelReport
{
client = c.ClientName,
cntyCounty = p.Countys. //Here is where i would like to say p.Countys.[CountyProperty]
sctSection = p.Countys.[CountyColectionForSections].[SectionProperty]
}
You could do the following if you expect only one County per Client and I'm guessing at the relation between the entities:
var x = from c in db.Client
from p in c.Prospects
from ct in p.Countys
select new ViewModelExcelReport
{
client = c.ClientName,
cntyCounty = ct.County,
sctSection = ct.Section
};
The first example works because he's only referencing a single instance of an entity (LivesIn of type City), and then referencing a single primitive value within (Name property is just a string).
I see you're trying to project a new type by referencing an IEnumerable (Countys), but you never actually enumerate/iterate/materialize an instance.
p.Countys.[CountyProperty] will never exist, because you have a reference to a collection and you must get a reference to a single object first. You can do that by using Countys.Single() or SingleOrDefault() but I doubt that's what you want. I think what you want is to traverse the model in the opposite direction. From the "Many" side to the "One" side. Something like this:
var x = from c in db.County
select new ViewModelExcelReport
{
County = c.Name,
CountyProperty = c.AnyProperty,
Section = c.Section.Name,
Prospect = c.Prospect.Name,
Client = c.Prospect.Client.Name
}
I have a large object graph that I want to return to the client (an overview of the entire model) so I decided to send it back as one big object (I'm returning it as the object in question.)
In Breeze however I'm only getting the first object in each dependent object. So for example I have a 'policy' object with two 'vehicle' objects. I only see one vehicle (even when I put a breakpoint at var p = data.results[0]. The json coming back from the call shows two vehicles but breeze is catching only one.
What can I do to get the other ones? Here's the call I'm making:
var getPolicyByPolicyNumber = function (lob, policynumber, policyObservable) {
var params = {};
params['lOBCd'] = lob;
params['policyNumber'] = policynumber;
var query = EntityQuery.from('PolicyInquiry')
.withParameters(params);
return manager.executeQuery(query)
.then(querySucceeded)
.fail(queryFailed);
function querySucceeded(data) {
var p = data.results[0];
p.completeTree(true);
return policyObservable(p);
}
};
And in my breeze controller I have the following:
[System.Web.Http.HttpGet]
public Policy PolicyInquiry(string lOBCd, string policyNumber)
{
UserProfile userProfile = _contextProvider.Context.UserProfiles.SingleOrDefault(u => u.UserName == WebSecurity.CurrentUserName);
var policy = Uow.PolicyServices.GetPolicy(userProfile.BrokerId, userProfile.AgencyId, "csio:" + lOBCd, policyNumber);
return policy;
}
And here's an abbreviated model showing policy and vehicle:
public class Policy
{
public int Id { get; set; }
public string PolicyNumber { get; set; }
[InverseProperty("Policy")]
public ICollection<Vehicle> Vehicles { get; set; }
// other fields removed
}
public class Vehicle
{
public int Id {get; set}
public string ItemId { get; set; }
// other fields removed
//Foreign Keys
public int PolicyId { get; set; }
[IgnoreDataMember]
[ForeignKey("PolicyId")]
[Required]
public virtual Policy Policy { get; set; }
}
Now that I see your model I think I see the issue.
Breeze does not automatically resolve the entity graph on a query. i.e. if you retrieve a Policy, Breeze only returns the Policy instance itself without any navigation properties resolved. This is by design, so that a single query doesn't bring down the entire entity graph.
If you want the values of any navigation properties you have three options, the third of which is probably your best bet. I've taken some liberties in simplifying your model for the purposes of explanation. These all assume that the "Policy" type is actually defined as a Breeze entity type, i.e. has a metadata definition in the Breeze metadataStore.
1) Use an client side EntityQuery.expand clause
var query = EntityQuery.from('Policy')
.expand("Vehicles")
.withParameters(params);
2) Use a server side Include clause
[System.Web.Http.HttpGet]
public IEnumberable<Policy>(string lOBCd, string policyNumber) {
return _contextProvider.Context.Policies.Where(....).Include("Vehicles");
}
3) Use a anonymous result, that contains two known entity types.
[System.Web.Http.HttpGet]
public Object PolicyInquiry(string lOBCd, string policyNumber) {
UserProfile userProfile = _contextProvider.Context.UserProfiles.SingleOrDefault(u => u.UserName == WebSecurity.CurrentUserName);
var policy = Uow.PolicyServices.GetPolicy(userProfile.BrokerId, userProfile.AgencyId, "csio:" + lOBCd, policyNumber);
return new {
Policy = policy,
Vehicles = policy.GetVehicles() // insure that they are actually resolved on the server)
}
return policy;
}
More info here: Navigation Properties
I hope this is clear enough.
Sorry, but without seeing the underlying implementation of "policy" and its metadata, it's hard to tell what's going on. But I can make a general suggestion.
1) If you want to return an aggregate object and have Breeze recognize it's constituent parts, the recommended mechanism is to create a projection and return that. i.e. something like
public IQueryable<Object> CompanyInfoAndOrders() {
return ContextProvider.Context.Customers.Select(c => new { Customer = c, Orders = c.Orders });
}
In this example, providing that Breeze has metadata for the Customer and Order types,
Breeze will deconstruct the result and add the Customer and its orders to the EntityManager, and return a collection of json objects each with a "Customer" and Orders property. The Customer and individual Orders will each have been "adapted" to the current model library as well (i.e. knockout, backbone, or backingStore - for Angular).
I cannot for the life of me get this to work with my existing code, but I am trying to save my enum selections as strings in NHibernate. Basically, I have a UI check box and if the user selects multiple check boxes I want to store those selections. Now, I can get NHibernate to store ONE selection (e.g., from a drop down or radio button list, where the user is limited to one choice only).
This is the jist of what I have for an enum:
public enum IncomeType
{
[Display(Name = "Full-Time Employment")]
FullTime,
[Display(Name = "Part-Time Employment")]
PartTime,
[Display(Name = "Self-Employment")]
SelfEmployed,
[Display(Name = "Rental")]
Rental,
[Display(Name = "Social Security Payments")]
SocialSecurity,
[Display(Name = "Retirement / Pension Payments")]
Retirement,
[Display(Name = "Child Support Payments")]
ChildSupport,
[Display(Name = "Spousal Maintenance")]
Maintenance,
[Display(Name = "Other")]
Other
}
I use a method to "select" whether a checkbox list is shown (if my BulkItemThreshold equals the number of options, a checkbox list is displayed). Here is that method:
public static IEnumerable<SelectListItem> GetItemsFromEnumString<T>
(T selectedValue = default(T)) where T : struct
{
return from name in Enum.GetNames(typeof(T))
let enumValue = Convert.ToString((T)Enum.Parse(typeof(T), name, true))
select new SelectListItem
{
Text = GetEnumDescription(name, typeof(T)),
Value = enumValue,
Selected = enumValue.Equals(selectedValue)
};
}
(Note: some items in there are helpers, but I don't believe they are relevant; also, the selected input is displayed using a template .cshtml file - again, not sure if that's relevant)
Now, I call this thusly:
public class IncomeTypeSelectorAttribute : SelectorAttribute
{
public override IEnumerable<SelectListItem> GetItems()
{
return Selector.GetItemsFromEnumString<IncomeType>();
}
}
And finally, we get to the virtual property (using a proxy) but this is where NHibernate throws a wrench (Note: this was working fine for me before NHibernate, and now I am trying to get many lines of code working with it WITHOUT having to re-do everything; if I re-do everything I will probably triple the code I already have to get it to work):
Property (record):
[IncomeTypeSelector(BulkSelectionThreshold = 9)]
public virtual List<string> IndividualIncomeTypeCheckBox { get; set; }
proxy (part):
public List<string> IndividualIncomeTypeCheckBox
{
get { return Record.IndividualIncomeTypeCheckBox; }
set { Record.IndividualIncomeTypeCheckBox = value; }
}
Again, this is how I was doing things and it was working great before NHibernate. But now I have to use NHibernate. No getting around it.
I am using a service class that it tying the two together in a Create method to save in the DB with NHibernate, and for the above it would ordinarily look like this:
part.IndividualIncomeTypeCheckBox = record.IndividualIncomeTypeCheckBox;
This would work if it were just one selection.
Well, I've spent a good two (2) months trying to get this to work. It's tough because I have lots of code where the user can make only one selection (such as with a radiobutton list) and it works GREAT - even with NHibernate. Let me give you an example:
public virtual IncomeType? IndividualIncomeTypeCheckBox { get; set; }
If I do the above, it will display a drop down list, and NHibernate will store the ONE allowable option selected by the user in the DB no problem. But more than one option with List<string> does not work.
Now, I have tried everything I could find here or elsewhere and nothing works. Yes, I know it should be IList<IncomeType> or some other variant. But if I use this then NHibernate requires that IncomeType be another table in the DB. This is too much code to write for such a simple thing I believe. We are not talking a many-to-many relation in the sense that this is not a User with Multiple addresses (wherein addresses would have street, city, state, zip, etc.).
I have tried different types of proxy get and set code, but nothing works. I have tried [Flags] and other things working with string only, but to no avail. Those last solutions would "work" but ONLY to save the first item selected out of multiple (i.e., in my scenario, if the user selected "FullTime" and "Rental" as Income Types, then only "FullTime" (string) would be saved or "1" ([Flags]/int), not both items selected.
I have a situation where I re-display the choices using a ReadOnly attribute like this:
[IncomeTypeSelector]
[ReadOnly(true)]
public List<string> IndividualIncomeTypeCheckBoxPost
{
get { return IndividualIncomeTypeCheckBox; }
}
This would display on the UI, but I tried doing something like this with NHibernate and it wouldn't work.
Could anyone please show me, using the above, how I can go about getting NHibernate to store more than one enum in this checkbox list scenario?
UPDATE:
More poking around here and on the web, and I came up with the following (which still does not work).
Property (record):
[IncomeTypeSelector(BulkSelectionThreshold = 9)]
public virtual IList<IncomeTypeRecord> IndividualIncomeTypeCheckBox
{
get { return incomeType; }
set { incomeType= value; }
}
private IList<IncomeTypeRecord> incomeType =
new List<IncomeTypeRecord>();
Proxy (part):
public IList<IncomeTypeRecord> IndividualIncomeTypeCheckBox
{
get { return Record.IndividualIncomeTypeCheckBox; }
set { Record.IndividualIncomeTypeCheckBox= value; }
}
And a change to the enum:
public enum IncomeType : int // removing int & value still gives validate error
{
[Display(Name = "Full-Time Employment")]
FullTime = 1,
[Display(Name = "Part-Time Employment")]
PartTime,
....
}
And I added this class to support IncomeTypeRecord
public class IncomeTypeRecord
{
public virtual int Id { get; set; }
public virtual IncomeType Value { get; set; }
}
HOWEVER, when I get to the UI screen and pick one or more options I get a validation error (value not valid). For example, say I pick FullTime alone, or pick FullTime and Retirement, then the UI will display the following error:
The value 'FullTime' is invalid.
The value 'FullTime,Retirement' is invalid.
(respectively)
Even if I remove the int declaration for the enum and get rid of the value I started with "1", I still get this validation error. I tried messing around with and adding different model binders (which now has me stumped as to whether my original problem still exists and now I have a different problem - but you still get bounty points :) ).
Pulling my hair out. If I could offer more bounty I would. I need a definitive solution. I appreciate any help.
UPDATE
This is what I have so far:
Record:
public virtual string IndividualIncomeTypeCheckBox{ get; set; }
Part:
//If I do IEnumberable<string> my .Select throws a cast error
public IEnumerable<IncomeType> IndividualIncomeTypeCheckBox
{
get
{
return Record
.IndividualIncomeTypeCheckBox
.Split(',')
.Select(r => (IncomeType)Enum.Parse(typeof(IncomeType), r));
}
set { Record.IndividualIncomeTypeCheckBox= value
== null ? null : String.Join(",", value); }
}
Service Class:
public SimplePart CreateSimple(SimplePartRecord record)
{
SimplePart simple = Services.ContentManager.Create<SimplePart>("Simple");
...
//How I would save a FirstName property (example Part / PartRecord below)
//public virtual string FirstName { get; set; } - PartRecord
//public string FirstName - Part
//{
// get { return Record.FirstName ; }
// set { Record.FirstName= value; }
//}
simple.FirstName = record.FristName;
...
//I obviously cannot do the following with the above IncomeType
//Getting cannot convert string to IEnumerable error
//How would I write this:
simple.IndividualIncomeTypeCheckBox = record.IndividualIncomeTypeCheckBox;
...
}
And this is how it's called in a controller (this persists to DB): (Updating Controller code)
public ActionResult Confirm(string backButton, string nextButton)
{
if (backButton != null)
return RedirectToAction("WrapUp");
else if ((nextButton != null) && ModelState.IsValid)
{
_myService.CreateSimple(myData.SimplePartRecord);
return RedirectToAction("Submitted");
}
else
return View(myData);
}
Updating with additional code (serialization and view model):
"myData" is defined in the controller (using Serialization) as:
private MyViewModel myData;
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var serialized = Request.Form["myData"];
if (serialized != null)
{
myData = (MyViewModel)new MvcSerializer().Deserialize
(serialized, SerializationMode.Signed);
TryUpdateModel(myData);
}
else
myData = (MyViewModel)TempData["myData"] ?? new MyViewModel();
TempData.Keep();
}
protected override void OnResultExecuted(ResultExecutedContext filterContext)
{
if (filterContext.Result is RedirectToRouteResult)
TempData["myData"] = myData;
}
I use Serialization because I set up a multi-step wizard (as seen in the controller action "backButton" "nextButton) on the front-end. I am not using a driver (which can only display Admin or on the front-end but then only on .cshtml files directly under the ~/Views folder (not in a structured folder list like I am using)). No driver = no update view model type code = no mechanism to "create" the data in the DB. If I do not use some "create" type method, the form will submit but all the data will be "NULL".
When you say that the data should be persisted automatically, I am sorry but I do not see how. All the stuff I read or code I review has SOME method of updating the DB with whatever is entered in a form. If I am missing something, my apologies.
"MyViewModel" is pretty straightforward:
[Serializabel]
public class MyViewModel
{
public SimplePartRecord SimplePartRecord { get; set; }
}
And, just in case, here is the relevant portion of the migration (return 1 is a completely separate and unrelated table):
public int UpdateFrom1()
{
SchemaBuilder.CreateTable("SimplePartRecord",
table => table
.ContentPartRecord()
...
.Column("IndividualIncomeTypeCheckBox", DbType.String)
...
);
ContentDefinitionManager.AlterPartDefinition("SimplePart",
part => part
.Attachable(false));
return 2;
}
The error I am getting is
Cannot implicitly convert type 'string' to 'System.Collections.Generic.IEnumerable'"
when I do the following in the "Create" method of my service class:
simple.IndividualIncomeTypeCheckBox = record.IndividualIncomeTypeCheckBox;
One additional thought: I tried using the n-n Relation sample to handle this scenario. Aside from it being a lot of extra code for what I thought should be straightforward and simple, because of the way I am using Serialization I had a lot of object reference errors and could not figure out how to properly code my controller to handle it.
There's a lot of info to wade through here so hopefully I haven't missed the point. It appears to me that the goals are:
The business class has a collection property of IList<IncomeType> without requiring an additional table
The values in that collection should be persisted as a delimited string of the enum names
The best approach is to use a custom user type (an implementation of NHibernate.UserTypes.IUserType) to map the property. Below is a generic IUserType that will map an enum of type T from an IList<T> property to a comma delimited string in the database and back again. There's no easy way to restrict T to an enum but the code will only work with enums.
Mapping a property using the custom type is simple with Fluent NHibernate:
public class Person
{
public Person()
{
IncomeTypes = new List<IncomeType>();
}
public virtual int PersonId { get; protected set; }
public virtual string FirstName { get; set; }
public virtual string LastName { get; set; }
public virtual IList<IncomeType> IncomeTypes { get; protected set; }
}
public class PersonMap : ClassMap<Person>
{
public PersonMap()
{
Table("Person");
Id(x => x.PersonId).GeneratedBy.Identity();
Map(x => x.FirstName);
Map(x => x.LastName);
Map(x => x.IncomeTypes).CustomType<EnumAsDelimitedStringType<IncomeType>>();
}
}
And here's the code for the user type:
public class EnumAsDelimitedStringType<T> : IUserType
{
public new bool Equals(object x, object y)
{
if (ReferenceEquals(x, y))
{
return true;
}
var xList = x as IList<T>;
var yList = y as IList<T>;
if (xList == null || yList == null)
{
return false;
}
// compare set contents
return xList.OrderBy(xValue => xValue).SequenceEqual(yList.OrderBy(yValue => yValue));
}
public int GetHashCode(object x)
{
return x.GetHashCode();
}
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
var outValue = NHibernateUtil.AnsiString.NullSafeGet(rs, names[0]) as string;
if (string.IsNullOrEmpty(outValue))
{
return new List<T>();
}
var getValueArray = outValue.Split(new[] {','}, StringSplitOptions.RemoveEmptyEntries);
return Array.ConvertAll(getValueArray, s => (T)Enum.Parse(typeof(T), s)).ToList();
}
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
var inValue = value as IList<T>;
// set to string.Empty if you prefer to store that instead of null when the collection is null or empty
object setValue = null;
if (inValue != null && inValue.Any())
{
var setValueArray = Array.ConvertAll(inValue.ToArray(), v => Enum.GetName(typeof(T), v));
setValue = string.Join(",", setValueArray);
}
NHibernateUtil.AnsiString.NullSafeSet(cmd, setValue, index);
}
public object DeepCopy(object value)
{
return value;
}
public object Replace(object original, object target, object owner)
{
return original;
}
public object Assemble(object cached, object owner)
{
return cached;
}
public object Disassemble(object value)
{
return value;
}
public SqlType[] SqlTypes
{
get { return new[] {new SqlType(DbType.AnsiString)}; }
}
public Type ReturnedType
{
get { return typeof(IList<T>); }
}
public bool IsMutable
{
get { return false; }
}
}
I think you're on the right track pursuing a [Flags] enum. You may have done this, but just in case -- making an enum flags-worthy is more than adding the attribute. You also have to specify the value for the items in a binary-friendly manner. I've found the easiest way to do this is as follows:
[Flags]
public enum IncomeType : long // you'll need the room with several options
{
FullTime = 1,
PartTime = 1 << 1,
SelfEmployed = 1 << 2
// And so on
}
If you don't do this, then you'll get sequential integer values, which breaks the bitwise comparison that allows you to do multiple values in a single integer.
Your code to create the SelectList looks fine. Your options should construct form values that get posted back with the same name. If you want to use the default modelbinder, that means the associated property on your view model would need to be List<int>. If you're not using a view model (you probably should) you can pull it out of the forms collection.
Once you have this set up, then translating from your view model to your NHibernate entity is simple if a little annoying. You basically have to cycle through the values in the list and |= them onto your NHibernate entity's single enum property.
So let's assume you have a view model like this:
public class MyEditViewModel
{
public string Name { get; set; }
public List<int> IncomeSelections { get; set; }
// You'll probably have this to populate the initial view rendering
public SelectList AllIncomeOptions { get; set; }
}
You'll build your view using your helpers and all that, then build the checkboxes using the SelectList but making sure the input name is IncomeSelections, then when it's posted back you will push the view model data into your NHibernate entity something like this:
var myNHEntity = new NHEntity();
// If you're editing an existing entity, then be sure to reset the enum
// value to 0 before going into the following foreach loop...
foreach (var incomeSelection in viewModel.IncomeSelections)
{
myNHEntity.IncomeSelection |= incomeSelection;
}
There's probably a more clever way to do this, and you might have to cast the int to your enum type, but you'll figure that out (I'd do it for you, but it is Friday and I already have a beer open).
NHibernate should persist it without you having to do anything funky on the NH side.
In summary...
It seems like this is more a problem of how you handle the posted data than the NHibernate side. If you implement something like this, then be sure to use Fiddler or FireBug to inspect the posted values to make sure 1) they're integers and 2) the names are the same so they'll be added to the list.
Good luck!
The problem is simply that it won't be able to map a List without building a full relationship with an intermediate association table. It is way simpler to have the record store the values as a comma-separated string (so your record property is a string, not a list of string) and your part can map back and forth between string and List.
You can find an example of something very close here:
https://bitbucket.org/bleroy/nwazet.commerce/src/d722cbebea525203b22c445905c9f28d2af7db46/Models/ProductAttributesPartRecord.cs?at=default
https://bitbucket.org/bleroy/nwazet.commerce/src/d722cbebea525203b22c445905c9f28d2af7db46/Models/ProductAttributesPart.cs?at=default
It's not using enum values, instead it's a list of ids, but that should give you a good idea about how to make this work fairly simply: parsing enums you already know how to do.
Let me know if you need more details, but I think that's what you needed to get unblocked.
I'm really trying hard to put everything on my project to work with the EF, but it's really getting difficult and sometimes it makes me wonder if it's really the smart move (to rely on EF against coding all the ins and outs of the database).
Well, my problem is still related to 1-N creating/editing/deleting functionality (something that should be simple, right?).
Ok, I'm pasting here some simple equivalent of my code.
For the Entities, I got the main class as:
[Table("OLIM_LOTE")]
public class Lote
{
[Key]
[Column("LOTE_ID_LOTE")]
public int? IDLote { get; set; }
[Column("LOTE_TX_OBS")]
public string Obs {get;set;}
[Column("LOTE_TX_DOCUMENTO_EXTRA")]
public string DocumentoExtra { get; set; }
[NotMapped]
public List<DocumentoLote> Documentos { get; set; }
public void LoadLists()
{
OlimpiqueDBContext myDbContext = new OlimpiqueDBContext();
var docs = (from doc in myDbContext.DocumentosLote
where doc.IDLote == this.IDLote
select doc);
this.Documentos = docs.ToList<DocumentoLote>();
}
}
[Notice that i used the nullable int? for Key - otherwise it throws me validation exception asking for a value on creation]
For the child class, i got this:
[Table("OLIM_DOCUMENTO_LOTE")]
public class DocumentoLote
{
[Key]
[Column("DOLO_ID_DOCUMENTO_LOTE")]
public int? IDDocumentoLote { get; set; }
[Column("DOCU_ID_DOCUMENTO")]
[ForeignKey("Documento")]
public int IDDocumento { get; set; }
public virtual Documento Documento { get; set; }
[Column("LOTE_ID_LOTE")]
[ForeignKey("Lote")]
public int IDLote { get; set; }
public virtual Lote Lote { get; set; }
}
[Notice that the child class has a reference back to the owner class, which are the "IDLote" and "Lote" attributes, and the owner class has a list of child class instances - so I got i bi-directional refernce - I assume that this is somehow related to the problems]
I got a Controller and View generated automatically by VS2012 with Read/Write functionality related to the class Lote.
What I did in the View can be described as: I used a Jquery DataTable to manage the child class data (the user can add "N" instances on the DataTable). I substituted the Post Button with a call to a JS method that simply gets all the data from the Form and from the DataTable and wrap it in a JSon object and send it to the controller via Ajax.
The controller method that receives it can be simplified as below:
[HttpPost]
public JsonResult Edit(Lote lote)
{
try
{
if (ModelState.IsValid) //<< HAVING PROBLEMS HERE... DETAILS BELOW
{
if (lote.IDLote.HasValue)
{
//Separete updates/inserts from deletes
List<int?> dbDocs = db.DocumentosLote
.Where(dt => dt.IDLote == lote.IDLote)
.Select(dt => dt.IDDocumentoLote)
.ToList();
List<int?> postedDocs = lote.Documentos
.Select(pt => pt.IDDocumentoLote)
.ToList();
List<int?> deletedDocs = dbDocs
.Except(postedDocs).ToList();
//Perform deletes
foreach (var delDocId in deletedDocs)
{
if (delDocId.HasValue)
{
DocumentoLote delDoc = db.DocumentosLote
.Where(dt => dt.IDLote == lote.IDLote && dt.IDDocumentoLote == delDocId)
.Single();
db.Entry(delDoc).State = EntityState.Deleted;
}
}
//Perform insert and updates
foreach (var doc in lote.Documentos)
{
if (doc.IDDocumentoLote.HasValue)
{
db.Entry(doc).State = EntityState.Modified;
}
else
{
db.Entry(doc).State = EntityState.Added;
doc.IDLote = (int)lote.IDLote;
}
}
}
else
{
db.Lotes.Add(lote);
}
db.SaveChanges();
// If Sucess== 1 then Save/Update Successfull else there it has Exception
return Json(new { Success = 1, ex = "" });
}
else
{
return Json(new { Success = 0, ex = "Falha ao tentar salvar os dados" });
}
}
catch (Exception ex)
{
// If Sucess== 0 then Unable to perform Save/Update Operation and send Exception to View as JSON
return Json(new { Success = 0, ex = ex.Message.ToString() });
}
}
Problems: Well I really passed through a lot to got to this point and now, I got only 2 problems. The first being that the creation is throwing a Validation Exception sayin that it needs an IDLote (for the child classes - but anyway, how would i have it if the owner class itself still doesn't have an Id at that point in creation?)
Second problem: Deletion dont work at all! Doesn't matter how i code it, it throws the exception "objects cannot be defined because they are attached to different ObjectContext objects". I really feel that this has something to do with the bidirectional reference between owner-children classes, but still, don't have a clue on exactly whats happening and how to solve it
I'm starting to feel really lost here. Any ideas on this would be very appreciated. Thanks
As there are a lot of views on this old question and now I do have some answer, I'm posting them for reference:
Q - Regarding the int? type for the key attributes:
A - It doesn't have to be a nullable int at all. The entity can be declared with a simple int attribute as key and when posting the JSon object from the View, back to some controller method, this attribute (the key) can be filled with the value "0". EF will generate the correct value as soon as it persists the object.
Q - Regarding the navigational attributes and how to implement the relation between the two classes when neither of them have already got a value (non-zero) on theis keys:
A - The JSon object to be sent back can implement the exact navigational relationaship between them. Wehn the controller binds the data posted to the model it should be receiving, it will "understand" their relationship and as soon as the values for the keys are generated, they will correctly reference one another.
Q - Regarding the error described on the delete method attempts:
A - When objects should interact with other objects, and those interactions should be persisted or "understood" by EF in any way, they must have been obtained, generated or attached to a same DBContext. EF rely on the DB context to create a tree of this interactions, thus, rendering impossible to build this tree when objets are not present on the same DB Context.
I want to add a relationship between multiple existing entities and another existing entity. Here is my model:
public class Term
{
public int TermId { get; set; }
public virtual ICollection<SubForm> SubForms { get; set; }
}
public class SubForm
{
public int SubFormId { get; set; }
public virtual ICollection<Term> Terms { get; set; }
}
I have an update repository method as follows:
public IQueryable<Term> GetTerms()
{
IQueryable<Term> query = db.Terms.AsNoTracking();
return query;
}
public Term UpdateTerm(Term term, IEnumerable<Expression<Func<Term, object>>> properties)
{
if (term.TermId == 0)
{
throw new InvalidOperationException("Term does not exist");
}
db.Terms.Attach(term);
if (properties != null)
{
foreach (var selector in properties)
{
string propertyName = Helpers.PropertyToString(selector.Body);
db.Entry(term).Property(propertyName).IsModified = true;
}
}
db.SaveChanges();
return term;
}
Now I assume this would work when I make this call in my service layer:
public void AddFormToTerm(int termId, int formId)
{
var term = termsRepository.GetTerms().FirstOrDefault(t => t.TermId == termId);
var subForms = termsRepository.GetSubForms().Where(t => t.FormId == formId);
//I assume this would work by adding existing forms to an existing term.
foreach (var subForm in subForms)
{
term.SubForms.Add(subForm);
}
termsRepository.UpdateTerm(term, null);
}
Unfortunately, this doesn't get updated, there is nothing in the intermediate table when I checked the database. No exception was also thrown.
Using AsNoTracking in this case is the problem. Without AsNoTracking it will work. You must keep in mind that you can update a many-to-many relationship only with the change tracking mechanism. But in your code the EF context will know about term and the SubForms collection for the first time when you call Attach in your UpdateTerm method. EF does not notice that you did add the SubForms to the term because those entities were not attached to the context (since you used AsNoTracking = "EF, please do not attach to the context!"). But after Attach nothing happened anymore before you called SaveChanges = No change = No database commands.
So removing AsNoTracking (or creating another method or a parameter to load with tracking) is the best option. Everything else will involve ugly "tricks" like this:
public Term UpdateTerm(Term term, ...)
{
//...
// Restore the state before adding the subforms = current state in DB
var tempSubForms = term.SubForms;
term.SubForms = null;
// Inform EF about this state = term exists, subforms exist
// in DB but no relationships
db.Terms.Attach(term);
foreach (var subForm in tempSubForms)
db.SubForms.Attach(subForm);
// Change the state: EF change tracking recognizes this
term.SubForms = tempSubForms;
//...
// EF now will send INSERT statements for the join table
db.SaveChanges();
return term;
}