I have an TaxWork entity which is persisted using NHibernate. This entity has the following properties (among others):
public virtual TaxWorkType Type { get; set; } //Kctc.TaxWorkType is an enumeration
public virtual TaxWorkStatus Status { get; set; } //Kctc.TaxWorkStatus is an enumeration
public virtual LegalWorkPriority Priority { get; set; } //Kctc.LegalWorkType is an enumeration
public virtual User Handler { get; set; } //Kctc.BusinessLayer.Entities.User is another entity
public virtual int? CaseNumber { get; set; }
I am using Linq to NHibernate to pull of a subset of the tax work objects as follows (taxWorkRepository.All obviously returns an IQueryable):
foreach (TaxWork taxWork in taxWorkRepository.All.Where(x => x.CaseNumber == _caseNumber).OrderBy(x => x.DateCreated))
{
...
}
This works fine. I want to use projection in order to query only the columns that are required in this case. I am usnig the following code:
foreach (var taxWorkFragment in taxWorkRepository.All.Where(x => x.CaseNumber == _caseNumber).OrderBy(x => x.DateCreated).Select(x => new { Type = x.Type, DateCreated = x.DateCreated, Handler = x.Handler, Status = x.Status, Priority = x.Priority }))
{
...
}
However, I'm getting the following error when trying to create the anonymous type:
Invalid cast from 'Kctc.TaxWorkStatus' to 'Kctc.BusinessLayer.Entities.User'.
Where on earth is it getting the idea that it should be casting a TaxWorkStatus to a User?
Any suggestions whatsoever what might be going wrong?
Try to make like this:
foreach (var taxWorkFragment in taxWorkRepository.All.Where(x => x.CaseNumber == _caseNumber).OrderBy(x => x.DateCreated)
.Select(x => new TaxWork { Type = x.Type, DateCreated = x.DateCreated, Handler = x.Handler, Status = x.Status, Priority = x.Priority }))
{
...
}
It should help
Related
I have a certain table in the database that stores the following objects:
public partial class Invoice
{
public string DocumentNumber { get; set; }
public DateTime? DocumentDate { get; set; }
public string DocumentReference { get; set; }
public string SerialNumber { get; set; }
public string ProductCode { get; set; }
public string Description { get; set; }
public string Certificate { get; set; }
public string Language { get; set; }
public string Email { get; set; }
}
I also have a query that returns me the number of specific elements:
SELECT Count(*)
FROM (
SELECT DocumentNumber,DocumentDate,DocumentReference
FROM vInvoiceSwivelInfoWeb
WHERE Email = 'someemail#gmail.com' AND Language = 'FR'
GROUP BY DocumentNumber,DocumentDate,DocumentReference
) AS T
The answer looks something like this:
How to use EF to make such a request and get a numerical answer?
I tried like this:
_context.Database.ExecuteSqlRawAsync($"..some SQL query..")
but I do not get the expected result.
UPD: Having received the answer about the impossibility of fulfilling this request through EF, the following question reasonably arose: Is it possible to make this request using LINQ?
You can Leverage ADO.NET via the Context.Database property.
Unfortunately, there is no way to get the count from the database using EF Core execute methods if you have a custom query that is not related to your entities.
using (var command = context.Database.GetDbConnection().CreateCommand())
{
command.CommandText = "SELECT Count(*) From Table1";
context.Database.OpenConnection();
using (var result = command.ExecuteReader())
{
// do something with result
}
}
for Updated question
var count = from a in _context.vInvoiceSwivelInfoWeb
where a.Email == "someemail#gmail.com" && a.Language == "FR"
group new { a.DocumentNumber , a.DocumentReference , a.DocumentDate } by a into g
select g.Count()
also, it's important to know which version of EF-Core are you using:
currently, if you are using EF-Core 3 group-by doesn't translate to SQL command so you have to do it on client-side:
check this link :
https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-3.0/breaking-changes#linq-queries-are-no-longer-evaluated-on-the-client
for EF-Core 3.0 - 3.1.1
var count = _context.vInvoiceSwivelInfoWeb
.Where(a => a.Email == "someemail#gmail.com" && a.Language == "FR" ).ToList()
.GroupBy(a => new { a.DocumentNumber ,a.DocumentDate, a.DocumentReference }).Count();
I have the following code:
var aaData = myapi.GetData().AsEnumerable().Select(x => new {
Id = x["myID"],
Desc = x["myDesc"]
});
Trying to do the following
aaData = aaData.OrderBy((string.Join(",", request.Order
.Select(x => request.Columns[x.Column].Data + " " + x.Dir))));
Getting error:
CS0266 Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<>' to 'System.Data.EnumerableRowCollection<>'. An explicit conversion exists (are you missing a cast?)
How to fix this?
GetData returns a DataTable
Request is an object having a property:
public OrderCol[] Order { get; set; }
OrderCol is
public class OrderCol {
public int Column { get; set; }
public string Dir { get; set; }
}
Thanks for your assistance.
The above code works for the case when I get a List<> back instead of DataTable. The error states that a Cast is needed and it seems to be how DataTable.AsEnumerable is set up as a EnumerableRowCollection
Can use a mock datatable to mimic the above
DataTable dt = new DataTable();
dt.clear();
dt.Columns.Add("myID");
dt.Columns.Add("myDesc");
all i needed was to convert to a list and things worked fine
There is something I don't fully understand with the code bellow. I'm trying to find the workers that have a duplicate module in their modules collection.
Here's the entities (simplified for the sake of brevity):
public class Worker
{
public int Id { get; private set; }
public ICollection<TakenTrainingModule> TakenTrainingModules { get; private set; }
public Worker()
{
TakenTrainingModules = new HashSet<TakenTrainingModule>();
}
}
public class TakenTrainingModule
{
public int Id { get; set; }
public int TrainingModuleId { get; set; }
}
And here's the query:
var query = from worker in _context.Workers.Include(worker => worker.TakenTrainingModules)
let distinctModules = worker.TakenTrainingModules.Select(module => module.TrainingModuleId).Distinct()
where worker.TakenTrainingModules.Count != distinctModules.Count()
select worker;
With the query bellow, the returned workers have their TakenTrainingModules collection empty.
But, with the next query (without using the keywork let), the collection is fully and correctly loaded:
var query = from worker in _context.Workers.Include(worker => worker.TakenTrainingModules)
where worker.TakenTrainingModules.Count != worker.TakenTrainingModules.Select(module => module.TrainingModuleId).Distinct().Count()
select worker;
What am I missing? Is the let keyword first executing the distinct query and fools the object state manager that the module are loaded but they aren't and the selector doesn't load them next?
Any explanations welcome! :-)
I've updated the query as this:
var query = from worker in _context.Workers
let distinctModules = worker.TakenTrainingModules.Select(module => module.TrainingModuleId).Distinct()
where worker.TakenTrainingModules.Count != distinctModules.Count()
select worker;
return query.Include(worker => worker.TakenTrainingModules).ToArray();
And everything is fine. Thanks to Dismissile for pointing me out a nice answer.
I'm trying to update a Customer in my database using ASP.NET Web API and Entity Framework 5 code-first, but it's not working. My entities look like this:
public class CustomerModel
{
public int Id { get; set; }
public string Name { get; set; }
// More fields
public ICollection<CustomerTypeModel> CustomerTypes { get; set; }
}
public class CustomerTypeModel
{
public int Id { get; set; }
public string Type { get; set; }
[JsonIgnore]
public ICollection<CustomerModel> Customers { get; set; }
}
Nothing all that special. I've built a web interface where users can add a customer by supplying the name and checking one or more customer types. When hitting the submit button, the data is sent to my Web API method:
public void Put([FromBody]CustomerModel customer)
{
using (var context = new MyContext())
{
context.Customers.Attach(customer);
context.Entry(customer).State = EntityState.Modified;
context.SaveChanges();
}
}
This updates the customer fields, but the related customer types are ignored. The incoming customer object does contain a list of CustomerTypes it should be associated with:
[0] => { Id: 1, Type: "Finance", Customers: Null },
[1] => { Id: 2, Type: "Insurance", Customers: Null }
[2] => { Id: 3, Type: "Electronics", Customers: Null }
But instead of looking at this list and adding/removing associated entities, EF just ignores it. New associations are ignored and existing associations remain even if they should be deleted.
I had a similar problem when inserting a customer into the database, this was fixed when I adjusted the state of these entities to EntityState.Unchanged. Naturally, I tried to apply this same magic fix in my update scenario:
public void Put([FromBody]CustomerModel customer)
{
using (var context = new MyContext())
{
foreach (var customertype in customer.CustomerTypes)
{
context.Entry(customertype).State = EntityState.Unchanged;
}
context.Customers.Attach(customer);
context.Entry(customer).State = EntityState.Modified;
context.SaveChanges();
}
}
But EF keeps displaying the same behavior.
Any ideas on how to fix this? Or should I really just do a manual clear to the list of CustomerTypes and then manually add them?
Thanks in advance.
JP
This is not really solvable by only setting entity states. You must load the customer from the database first including all its current types and then remove types from or add types to the loaded customer according to the updated types collection of the posted customer. Change tracking will do the rest to delete entries from the join table or insert new entries:
public void Put([FromBody]CustomerModel customer)
{
using (var context = new MyContext())
{
var customerInDb = context.Customers.Include(c => c.CustomerTypes)
.Single(c => c.Id == customer.Id);
// Updates the Name property
context.Entry(customerInDb).CurrentValues.SetValues(customer);
// Remove types
foreach (var typeInDb in customerInDb.CustomerTypes.ToList())
if (!customer.CustomerTypes.Any(t => t.Id == typeInDb.Id))
customerInDb.CustomerTypes.Remove(typeInDb);
// Add new types
foreach (var type in customer.CustomerTypes)
if (!customerInDb.CustomerTypes.Any(t => t.Id == type.Id))
{
context.CustomerTypes.Attach(type);
customerInDb.CustomerTypes.Add(type);
}
context.SaveChanges();
}
}
A cleaner solution would be:
public void Put([FromBody]CustomerModel customer)
{
using (var context = new MyContext())
{
var customerInDb = context.Customers.Include(c => c.CustomerTypes)
.Single(c => c.Id == customer.Id);
// Updates the Name property
context.Entry(customerInDb).CurrentValues.SetValues(customer);
// Remove types
customer.CustomerTypes.Clear();
// Add new types
foreach (var type in customer.CustomerTypes)
{
context.CustomerTypes.Attach(type);
customerInDb.CustomerTypes.Add(type);
}
context.SaveChanges();
}
}
I've been fiddling about and trying multiple things, but I'm going wrong somewhere. I tried to make my first attempt using AutoMapper as simple as possible. I'm trying to create a new Brand and save it to the database, using a CreateBrandViewModel. Some of this might look a bit fruity, but I was trying to get it to work in the simplest way possible.
Domain:
public class Brand : EntityBase
{
public virtual string Name { get; set; } //Not Nullable
public virtual bool IsActive { get; set; } // Not Nullable
public virtual Product DefaultProduct { get; set; } // Nullable
public virtual IList<Product> Products { get; set; } // Nullable
}
ViewModel:
public class CreateBrandViewModel
{
public string Name { get; set; }
public bool IsActive { get; set; }
}
Controller
this is where I've been playing about the most for a while, so it looks a bit strange now. The commented out code hasn't resolved my problem.
[HttpPost]
public ActionResult Create(CreateBrandViewModel createBrandViewModel)
{
if(ModelState.IsValid)
{
Mapper.CreateMap<Brand, CreateBrandViewModel>();
//.ForMember(
// dest => dest.Name,
// opt => opt.MapFrom(src => src.Name)
//)
//.ForMember(
// dest => dest.IsActive,
// opt => opt.MapFrom(src => src.IsActive)
//);
Mapper.Map<Brand, CreateBrandViewModel>(createBrandViewModel)
Session.SaveOrUpdate(createBrandViewModel);
return RedirectToAction("Index");
}
else
{
return View(createBrandViewModel);
}
}
Just for the record, BrandController inherits from SessionController (Ayendes way), and transactions are managed through an ActionFilter. Though thats is a bit irrelevant I think. I've tried various different ways so I have different error messages - if you can take a look at whats happening and tell me how you might expect to use it that would be great.
For reference, my fluent nhibernate mapping for Brand:
public class BrandMap : ClassMap<Brand>
{
public BrandMap()
{
Id(x => x.Id);
Map(x => x.Name)
.Not.Nullable()
.Length(50);
Map(x => x.IsActive)
.Not.Nullable();
References(x => x.DefaultProduct);
HasMany(x => x.Products);
}
}
Edit 1
I just tried the following code, but putting a breakpoint on Session.SaveOrUpdate(updatedModel) the fields are null and false, when they shouldn't be:
var brand = new Brand();
var updatedBrand = Mapper.Map<Brand, CreateBrandViewModel>(brand, createBrandViewModel);
Session.SaveOrUpdate(updatedBrand);
return RedirectToAction("Index");
}
You appear to be doing your mapping the wrong way around on your return trip from the post. The alternative syntax may help out here, try:
// setup the viewmodel -> domain model map
// (this should ideally be done at initialisation time, rather than per request)
Mapper.CreateMap<CreateBrandViewModel, Brand>();
// create our new domain object
var domainModel = new Brand();
// map the domain type to the viewmodel
Mapper.Map(createBrandViewModel, domainModel);
// now saving the correct type to the db
Session.SaveOrUpdate(domainModel);
let me know if that cracks the egg... or just egg on yer face again :-)