I have a class in Entity framework 5 (using MVC 4):
public class JobFunction
{
public int Id { get; set; }
public string JobFunctionName { get; set; }
public int StatusId { get; set; }
public Status JFStatus { get; set; }
}
In my OnModelCreating method, I establish a FK relationship with the Status table as follows:
modelBuilder.Entity<JobFunction>().HasRequired(a => a.JFStatus).
WithMany().HasForeignKey(u => u.StatusId).WillCascadeOnDelete(false);
In my controller, I get a list of JobFunction objects as follows:
List<JobFunction> jfList = uow.JobFunctionRepository.GetAll().ToList<Catalog>();
where uow is my Unit of Work object, and JobFunctionRepository is defined. When I examine any JobFunction object in jfList, I see the following in my watch window:
Id: 1
JfStatus: null
JobFunctionName: "Manager"
StatusId: 2
Note that JFStatus is null. My question is: what provisions do I make in my code to initialize JFStatus to the appropriate Status object (based on the value of StatusId), during my GetAll call?
Thanks in advance.
-Zawar
You need some instrument to apply eager loading when you load the data through your repository. For example you could give your GetAll method a parameter list of expressions for the navigation properties you want to include in your query:
using System.Data.Entity;
//...
public IQueryable<JobFunction> GetAll(
params Expression<Func<JobFunction, object>>[] includes)
{
IQueryable<JobFunction> query = context.JobFunctions;
foreach (var include in includes)
query = query.Include(include);
return query;
}
Then you call it like so:
List<JobFunction> jfList = uow.JobFunctionRepository
.GetAll(jf => jf.JFStatus)
.ToList();
The JFStatus property should be filled now.
Related
I have an index.chtml set up with about 10 ActionLinks. Those actionLinks trigger different ActionResult functions within the controller since each of them essentially perform unique queries on a data model.
I also have an entities object named db which has all the data. Instead of just displaying all the data, I want to perform complex filtering on the entities object to find where certain properties of records are null or where a property is greater than some input then returns a view of all columns on only those records that were filtered.
Find nulls:
public class printJobsController : Controller {
private PrintJobsEntities db = new PrintJobsEntities
public ActionResult IncompleteJobs {
//get jobs where processDate is null
...
}
}
Find where count is greater than 10:
public class printJobsController : Controller {
private PrintJobsEntities db = new PrintJobsEntities
public ActionResult JobsGreaterThan(int limit) {
//group by printerName and find counts greater than limit
...
}
}
How do I go about doing this?
Seems you are trying to populate the View with filtered data as per your request parameter in controller action.
You could follow the below steps to achieve what you are trying to:
Your imaginary Data Model
public class PrinterJob
{
[Key]
public int PrinterId { get; set; }
public string PrinterName { get; set; }
public int PrintedBy { get; set; }
public int TotalPrint { get; set; }
}
Sample Data In Database:
Controller Action:
public ActionResult <PrinterJob> JobsGreaterThan(int limit) {
var printCountByGroup =
(from objPrint in _context.PrinterJobs group objPrint by new {
objPrint.PrinterName, objPrint.PrintedBy, objPrint.TotalPrint
}
into grp where grp.Sum(p => p.TotalPrint) > limit
select new {
PrinterName = grp.Key.PrinterName, PrintedBy = grp.Key.PrintedBy,
TotalPrint = grp.Key.TotalPrint
});
return View(printCountByGroup);
}
Output After Applying Filter:
Note: Here I am trying to filter printer information which printed more then 30 printing jobs.
Hope it would help you to achieve your goal. If you still have any problem feel free to let me know.
I have this entity:
public int Id { get; private set; }
public string Name { get; private set; }
public Behavior Behavior { get; private set; }
public Product(int id, string name, Behavior behavior)
{
Id = id;
Name = name;
Behavior = behavior;
}
In startup method I'm registering the EdmModel :
var builder = new ODataConventionModelBuilder();
var entitySet = builder.EntitySet<Product>("Products");
entitySet.EntityType.HasKey(x => x.Id);
var model = builder.GetEdmModel();
app.UseMvc(route =>
{
route.Select().Filter().Expand().OrderBy().Count().MaxTop(null);
route.MapODataServiceRoute("odata", null, model);
route.EnableDependencyInjection();
}
);
When I'm running my app, this exception occurs:
InvalidOperationException: The entity 'Product' does not have a key
defined.
If I change private setter to public all is working. Also others properties with private setters are giving: ODataException Product does not contain property with name 'Name'. How can I solve it ?
the question is quite old, I stumbled across the same issue now. Scalar properties (i.e. int, string, bool) with private setters are not recognized by the ODataConventionModelBuilder, even though it recognizes collections with private setters.
I could solve the problem using EntityTypeConfiguration<T> obtained via the model builder:
public class Article
{
public string ArticleNr { get; private set; }
public string SomeProperty { get; private set; }
}
var builder = new ODataConventionModelBuilder();
var articleBuilder = builder.EntityType<Article>();
articleBuilder.HasKey(a => a.ArticleNr);
articleBuilder.Property(a => a.SomeProperty);
builder.EntitySet<Article>("Articles");
var model = builder.GetEdmModel();
This is giving me a model that can be built, it recognizes the key in spite of its private setter and I can also issue queries against SomeProperty. But this way every property must be registered explicitly using a call to Property which seems very error prone when adding new properties. I think it should be able to write a custom convention for it, but I have not tried this so far.
I have a CustomerOrder-view where I would like to change an existing CustomerOrder.
I have a viewmodel that very simpliefied looks something like this:
public class CustomerOrderViewModel
{
public int ID { get; set; }
public Customer Customer { get; set; }
public DateTime Date { get; set; }
public IEnumerable<OrderRow> OrderRows { get; set; }
}
public class OrderRow
{
public int id { get; set; }
public int price { get; set; }
}
public class Customer
{
public string Name { get; set; }
}
I also have a database with mapping tables / fields.
In my GET Action Method I load the Order with the help of Automapper like this:
var customerOrder = using (var ctx = new My_Entities()) {
return ctx.CustomerOrders.
Include("Orderrows").
Include("Customer").
Single(o => o.CustomerOrderID == id);
}
var model= AutoMapper.Mapper.DynamicMap<DataAccessLayer.CustomerOrder, CustomerOrderViewModel>(customerOrder);
In the View I use Knockout to bind to a viewmodel there, where the user can update the CustomerOrder. That includes editing Customer information and adding new orderrows etc.
Then in the post back a map the ViewModel back to the ObjectContext CustomerOrder:
var customerOrderToBeSaved =
AutoMapper.Mapper.DynamicMap<CustomerOrderViewModel, CustomerOrder>(
customerOrderViewModel);
try
{
using (var ctx = new MyEntities())
{
ctx.CustomerOrders.Attach(customerOrderToBeSaved);
ctx.CustomerOrders.ApplyCurrentValues(customerOrderToBeSaved);
...
ctx.SaveChanges();
}
}
I get the error message: An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key.
OK, that I can understand. But how should I go about this? Can I get the existing object and apply Changes to that one, because that is really what I'd like. I've tried to look up the old one and detach it but I haven't got it to wrok.Perhaps I'm doing this in a completely wrong way. Please advice.
You should not attach customerOrderToBeSaved, see MSDN about the argument of ApplyCurrentValues.
The detached object that has property updates to apply to the original object.
So you've got to load the entity from the database into the context and then ApplyCurrentValues with the detached object that has the new values.
You don't have to load the row from the database to update it.
You can do something like this:
var entity = ctx.CustomerOrders.Attach(customerOrderToBeSaved);
ctx.Entry( entity ).State = EntityState.Modified;
ctx.SaveChanges();
This will tell EF to issue an UPDATE SQL statement that overwrites all the columns in the record.
You can select which columns you want to update like this:
var entity = ctx.CustomerOrders.Attach(customerOrderToBeSaved);
var entry = ctx.Entry( entity );
entry.Property( o => o.<ColumnPropertyToUpdate> ).IsModified = true;
entry.Property( o => o.<ColumnPropertyToUpdate> ).IsModified = true;
...
ctx.SaveChanges();
If you do this, EF will only include the columns you've marked as modified in the UPDATE statement.
I'm developing a project using Silverlight 4 and Entity Framework 4 and I'm trying to auto-load the details (with conditions) associated with an entity when the client loads the EntityQuery.
So far, I've been able to put in place a solution, using the Include attribute, that returns all the details associated with the master entity. What I'm missing here is to be able to filter out the details based on some criteria.
As an example, here's what my entities look like:
Entity Movie
Id (int)
[Include]
MovieLocalizedInformations (EntityCollection<MovieLocalizedInformation>)
Entity MovieLocalizedInformation
Id (int)
Movie_Id (int)
LanguageCode (eg.: en)
Title
On my DomainService object, I expose the following method:
public IQueryable<Movie> GetMovies( string languageCode )
{
return this.ObjectContext.Movies.Include( "MovieLocalizedInformations" );
}
This works fine. But when I try to add where clause to filter out the localized information based on the language code, only the movies get loaded on the client.
Is there a way to achieve the filtering in one query?
Note: I'm also using the DomainDataSource with paging on the client so the solution needs to work with that.
Any help would be greatly appreciated!
Thanks,
Jacques.
Not sure about Enitity Framework but with a LinqToSqlDomainService you use the LoadWith loadOption
to include the details entities and then use the AssociateWith LoadOption to filter the detail e.g
DataLoadOptions options = new DataLoadOptions();
options.LoadWith<Movies>(i => i.MovieLocalizedInformations);
options.AssociateWith<Movies>(i => i.MovieLocalizedInformations.Where(d=> myListOfIds.Contains(d.LocationId)));
Ok,
For efficiency reason, I decided to go with custom DTO object that fetches the localized information and flatten the result.
But, the same problem occurred when my custom DTO needed to reference another custom localized DTO.
Here is how I came to do the same as the .Include( "PropertyName" ) that the ObjectSet offers:
Entity LocalizedMovieCollection
public class LocalizedMovieCollection
{
[Key]
public int Id { get; set; }
public string Name { get; set; } (the result of a sub query based on the language)
[Include]
[Association( "LocalizedMovieCollection_LocalizedMovies", "Id", "MovieCollection_Id" )]
public IEnumerable<LocalizedMovie> Movies { get; set; }
}
Entity LocalizedMovie
public class LocalizedMovie
{
[Key]
public int Id { get; set; }
public string Name { get; set; } (the result of a sub query based on the language)
public int MovieCollection_Id { get; set; }
[Include]
[Association( "LocalizedMovie_LocalizedMovieCollection", "MovieCollection_Id", "Id", IsForeignKey = true]
public LocalizedMovieCollection MovieCollection { get; set; }
}
Then, I've declared two methods: One that returns an IQueryable of LocalizedMovieCollection and the other, an IQueryable of LocalizedMovie. (Note: There must be at least one method that returns each type of entity for the entity to get auto-generated on the Silverlight client)
My goal is to automatically load the MovieCollection associated with a Movie so the method definition to get the movies is as follow:
public IQueryable<LocalizedMovie> GetMovies( string languageCode )
{
return from movie in this.ObjectContext.Movies
join movieLocalizedInfo in this.ObjectContext.MovieLocalizedInformations
on movie equals movieLocalizedInfo.Movie
join movieCollection in this.ObjectContext.MovieCollections
on movie.MovieCollection equals movieCollection
join movieCollectionLocalizedInfo in this.ObjectContext.MovieCollectionLocalizedInformations
on movieCollection equals movieCollectionLocalizedInfo.MovieCollection
where movieLocalizedInfo.LanguageCode == languageCode && movieCollectionLocalizedInfo.LanguageCode == languageCode
select new LocalizedMovie()
{
Id = movie.Id,
Name = movieLocalizedInfo.Name
MovieCollection_Id = movieCollection.Id,
MovieCollection = new LocalizedMovieCollection(){ Id = movieCollection.Id, Name = movieCollectionLocalizedInfo.Name }
}
}
When the Silverlight client loads the query, all the LocalizedMovies and their associated LocalizedMovieCollections will be loaded into the context.
Consider the following situation. I have an Entity named ProductSupplier that is a Presentation Model. It is created by doing an inner join of Products and Suppliers, and creating a new projection from a Linq statement. The ProductSupplier projection also creates a list of PartType objects, which is also a Presentation Model.
public partial class ProductSupplier
{
private IEnumerable<PartType> _partTypes;
[Key]
public int ProductSupplierKey { get; set }
[Include]
[Association("ProductSupplier_PartType", "ProductSupplierKey", "ProductSupplierKey")]
public IEnumerable<PartType> PartTypes
{
get { return _partTypes ?? (_partTypes = new List<PartType>()); }
set { if (value != null) _partTypes = value; }
}
}
public partial class PartType
{
[Key]
public int PartTypeKey { get; set; }
[Key]
public int ProductSupplierKey { get; set; }
public int PartQuantity { get; set; }
}
I want to have a validation that is no ProductSupplier can be have more than 10 separate parts. This means that all PartQuantities for all PartTypes that belong to a ProductSupplier should be summed, and the total cannot exceed 10.
For this, I created a custom validator:
public static ValidationResult ValidatePartTotals(ProductSupplier productSupplier, ValidationContext validationContext)
{
if (productSupplier.PartTypes.Sum(p => p.PartQuantity) > 10)
return new ValidationResult("Must be less than 10 parts total.");
return ValidationResult.Success;
}
This works fine when validation is called from the client-side. The problem I'm having is that when the validator is run from the server-side, the IEnumerable is always empty.
I have tried adding [RoundTripOriginal] to the PartQuantity, and to various other properties, such as all the Key fields, but it still is an empty list when done on the server side.
How can I access these PartType objects when validation is run on the server?
Unfortunately, you don't have any guarantees as to the state of the object graph when it gets to you on the server. RIA optimizes things so you'll only see modified entities. One solution would be to use composition. It will make sure the whole graph is passed around, but it has other effects that may not be what you want. Another option would be to hydrate the graph in your update method, then perform validation, and throw a ValidationException as necessary.