Develop Reference

Push records from one model array to another model array with conditions

I have below two models:
TrackList:
public int id { get; set; }
public string name { get; set; }
public int apr_by { get; set; }
public int reg_by { get; set; }
TrackListMain:
public int id { get; set; }
public string name { get; set; }
public string status { get; set; }
Suppose I would get the below records from DB in the model array TrackList by executing:
var dbArray = await _SQLHelper.GetRecords<TrackList>("[TASKLIST]", parameters);
id
name
apr_by
reg_by
1
aaa
1
1
2
bbb
2
null
3
ccc
null
3
4
ddd
null
null
Now I need to push each record to the model array TrackListMain based on these conditions:
foreach dbArray => {
if (`dbArray.apr_by` == null && `reg_by` == null), push to `TrackListMain` and update `status` field with `null`
if `dbArray.apr_by` !=null, push to `TrackListMain` and update `status` field with `AB`
if `dbArray.reg_by` !=null, push to `TrackListMain` and update `status` field with `RB`
}
And my resultant array IEnumerable<TrackListMain> mainArray should contain data with the below format:
id
name
status
1
aaa
AB
1
aaa
RB
2
bbb
AB
3
ccc
RB
4
ddd
null
Can you help me to achieve this in C# either by using LINQ?

For LINQ approach,
Filter data by conditions (3 sets) and decorate the output result.
Combine 3 set of data into one with .Union().
Order the result by Id.
List<TrackListMain> result = (dbArray.Where(x => x.Apr_By == null && x.Reg_By == null)
.Select(x => new TrackListMain
{
Id = x.Id,
Name = x.Name,
Status = null
})
)
.Union(dbArray.Where(x => x.Apr_By != null)
.Select(x => new TrackListMain
{
Id = x.Id,
Name = x.Name,
Status = "AB"
})
)
.Union(dbArray.Where(x => x.Reg_By != null)
.Select(x => new TrackListMain
{
Id = x.Id,
Name = x.Name,
Status = "RB"
})
)
.OrderBy(x => x.Id)
.ToList();
Demo # .NET Fiddle

First of all you should make sure how the _SQLHelper behaves if the values in database are null.
If it returns null then you need to make the class properties nullable:
TrackList
public int id { get; set; }
public string name { get; set; }
public int? apr_by { get; set; }
public int? reg_by { get; set; }
Otherwise it makes no sense to check them for null in C# (then you would probably check if they are 0 which is int default value).
The query could look like this:
You need this using:
using System.Linq;
var mainArray = dbArray.Select(x => new TrackListMain
{
id = x.id,
name = x.name,
status = x.apr_by == null ? (x.reg_by == null ? null : "RB") : "AB"
});
It is not very readable tho, so maybe better go with a method:
var mainArray = dbArray.Select(ConvertTrackList);
private static TrackListMain ConvertTrackList(TrackList trackList)
{
var main = new TrackListMain()
{
id = trackList.id,
name = trackList.name
};
if (trackList.apr_by != null)
main.status = "AB";
else if (trackList.reg_by != null)
main.status = "RB";
return main;
}

Joining two lists of object optimization

I am looking for a way of optimizing my LINQ query.
Classes:
public class OffersObject
{
public List<SingleFlight> Flights { get; set; }
public List<Offer> Offers { get; set; } = new List<Offer>();
}
public class SingleFlight
{
public int Id { get; set; }
public string CarrierCode { get; set; }
public string FlightNumber { get; set; }
}
public class Offer
{
public int ProfileId { get; set; }
public List<ExtraOffer> ExtraOffers { get; set; } = new List<ExtraOffer>();
}
public class ExtraOffer
{
public List<int> Flights { get; set; }
public string Name { get; set; }
}
Sample object:
var sampleObject = new OffersObject
{
Flights = new List<SingleFlight>
{
new SingleFlight
{
Id = 1,
CarrierCode = "KL",
FlightNumber = "1"
},
new SingleFlight
{
Id = 2,
CarrierCode = "KL",
FlightNumber = "2"
}
},
Offers = new List<Offer>
{
new Offer
{
ProfileId = 41,
ExtraOffers = new List<ExtraOffer>
{
new ExtraOffer
{
Flights = new List<int>{1},
Name = "TEST"
},
new ExtraOffer
{
Flights = new List<int>{2},
Name = "TEST"
},
new ExtraOffer
{
Flights = new List<int>{1,2},
Name = "TEST"
}
}
}
}
};
Goal of LINQ query:
List of:
{ int ProfileId, string CommercialName, List<string> fullFlightNumbers }
FullFlightNumber should by created by "Id association" of a flight. It is created like: {CarrierCode} {FlightNumber}
What I have so far (works correctly, but not the fastest way I guess):
var result = sampleObject.Offers
.SelectMany(x => x.ExtraOffers,
(a, b) => {
return new
{
ProfileId = a.ProfileId,
Name = b.Name,
FullFlightNumbers = b.Flights.Select(f => $"{sampleObject.Flights.FirstOrDefault(fl => fl.Id == f).CarrierCode} {sampleObject.Flights.First(fl => fl.Id == f).FlightNumber}").ToList()
};
})
.ToList();
Final note
The part that looks wrong to me is:
.Select(f => $"{sampleObject.Flights.FirstOrDefault(fl => fl.Id == f)?.CarrierCode} {sampleObject.Flights.FirstOrDefault(fl => fl.Id == f)?.FlightNumber}").ToList()
I am basically looking for a way of "joining" those two lists of the OffersObject by Flight's Id.
Any tips appreciated.

If there will only be a few flights defined in sampleObject.Flights, a sequential search using a numeric key is hard to beat.
However, if the number of flights times the number of offers is substantial (1000s or more), I would suggest loading the list of flights into a dictionary with Id as the key for efficient lookup. Something like:
var flightLookup = sampleObject.Flights.ToDictionary(f => f.Id);
And then calculate your FullFlightNumbers as
FullFlightNumbers = b.Flights
.Select(flightId => {
flightLookup.TryGetValue(flightId, out SingleFlight flight);
return $"{flight?.CarrierCode} {flight?.FlightNumber}";
})
.ToList()
TryGetValue above will quietly return a null value for flight if no match is found. If you know that a match will always be present, the lookup cold alternately be coded as:
SingleFlight flight = flightLookup[flightId];
The above also uses a statement lambda. In short, lambda functions can have either expression or statement blocks as bodies. See the C# reference for more information.

I'd suggest replacing the double .FirstOrDefault() approach with .IntersectBy(). It is available in the System.Linq namespace, starting from .NET 6.
.IntersectBy() basically filters sampleObject.Flights by matching the flight ID for each flight in sampleObject with flight IDs in ExtraOffers.Flights.
In the code below, fl => fl.Id is the key selector for sampleObject.Flights (i.e. fl is a SingleFlight).
var result = sampleObject.Offers
.SelectMany(x => x.ExtraOffers,
(a, b) => {
return new
{
ProfileId = a.ProfileId,
Name = b.Name,
FullFlightNumbers = sampleObject.Flights
.IntersectBy(b.Flights, fl => fl.Id)
.Select(fl => fl.FullFlightNumber) // alternative 1
//.Select(fl => $"{fl.CarrierCode} {fl.FlightNumber}") // alternative 2
.ToList()
};
})
.ToList();
In my suggestion I have added the property FullFlightNumber to SingleFlight so that the Linq statement looks slightly cleaner:
public class SingleFlight
{
public int Id { get; set; }
public string CarrierCode { get; set; }
public string FlightNumber { get; set; }
public string FullFlightNumber => $"{CarrierCode} {FlightNumber}";
}
If defining SingleFlight.FullFlightNumber is not possible/desirable for you, the second alternative in the code suggestion can be used instead.
Example fiddle here.

Code review of this portion of Linq Filters

I am a newbie of c #, I would like to know if I can remove the for each and do a single operation with Linq. I would like to return an IEnumerable with already filtered. is it possible to do this? Every suggestion is welcome, thank you very much
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Linq
{
class Oggetto
{
public int Id { get; set; }
public string MyProperty { get; set; }
public int Deleted { get; set; }
}
class Program
{
static void Main(string[] args)
{
IEnumerable<Oggetto> lista = new List<Oggetto> {
new Oggetto(){ Id = 1, MyProperty = "Propr1", Deleted = 0 },
new Oggetto(){ Id = 1, MyProperty = "Propr2", Deleted = 1 },
new Oggetto(){ Id = 2, MyProperty = "Prop3", Deleted = 0 },
new Oggetto(){ Id = 3, MyProperty = "Propr4", Deleted = 0 },
new Oggetto(){ Id = 3, MyProperty = "Prop5", Deleted = 1 }
};
foreach (var item in lista.Where(x => x.Deleted == 1).GroupBy(x => x.Id).Select(g => g.First()))
{
item.MyProperty = string.Join(",", lista.Where(t => t.Id == item.Id).Select(x => x.MyProperty).ToArray());
Console.WriteLine(item.Id);
Console.WriteLine(item.MyProperty);
}
Console.ReadLine();
}
}
}

You can use projection for this.
var orderedList = lista.GroupBy(x => x.Id)
.Where(x => x.Any(y => y.Deleted == 1))
.Select(x => new Oggetto
{
Id = x.Key, MyProperty = string.Join(",", x.Select(v => v.MyProperty))
});
foreach (var item in orderedList)
{
Console.WriteLine(item.Id);
Console.WriteLine(item.MyProperty);
}
Anyway, as #Alex said you shoud replace Deleted field type to bool and as said by #Marco Salerno start programming in English you'll not regret.

First of all I would avoid the groupBy statement. This is a lot of unneded overhead. You can use distinct instead. This will give you all the IDs you need to know.
var ids = lista.Where(x => x.Deleted).Select(x => x.Id).Distinct();
You can then select all the elements that you need with:
var items = ids.Select(i => lista.Where(x => x.Id == i));
which results in a List of Lists. For the ease of use I would convert this to a Dictionary<K, V> (int this case it's Dictionary<long, List<string>> as a final step:
var dictionary = items.ToDictionary(l => l.First().Id, l => l.Select(o => o.MyProperty).ToList());
You now got a "nice and filtered" collection you can use any way you like (or just output it)
foreach (var item in dictionary)
{
Console.WriteLine($"Id: {item.Key}");
Console.WriteLine($"Properties: {string.Join(", ", item.Value)}");
}
I also changed your class a little bit to:
class Oggetto
{
public int Id { get; set; }
public string MyProperty { get; set; }
// bool instead of int - Deleted has only 2 states
public bool Deleted { get; set; }
}

First of all STOP programming in Italian, start doing it in English.
Anyway, this should be a better approach:
class Program
{
static void Main(string[] args)
{
List<Item> items = new List<Item> {
new Item{ Id = 1, MyProperty = "Propr1", Deleted = 0 },
new Item{ Id = 1, MyProperty = "Propr2", Deleted = 1 },
new Item{ Id = 2, MyProperty = "Prop3", Deleted = 0 },
new Item{ Id = 3, MyProperty = "Propr4", Deleted = 0 },
new Item{ Id = 3, MyProperty = "Prop5", Deleted = 1}
};
foreach (IGrouping<int,Item> group in items.GroupBy(x => x.Id).ToList())
{
List<Item> groupItems = group.ToList();
Item deletedItem = groupItems.Where(x => x.Deleted == 1).FirstOrDefault();
if(deletedItem != null)
{
deletedItem.MyProperty = string.Join(",", groupItems.Select(x => x.MyProperty).ToArray());
Console.WriteLine(deletedItem.Id);
Console.WriteLine(deletedItem.MyProperty);
}
}
}
}
class Item
{
public int Id { get; set; }
public string MyProperty { get; set; }
public int Deleted { get; set; }
}

EF get list of parent entities that have list of child

I have to next 2 entities in my project
public class Product
{
public Product()
{
this.ProductImages = new HashSet<ProductImage>();
this.ProductParams = new HashSet<ProductParam>();
}
public int ID { get; set; }
public int BrandID { get; set; }
public int CodeProductTypeID { get; set; }
public string SeriaNumber { get; set; }
public string ModelNumber { get; set; }
public decimal Price { get; set; }
public bool AvailableInStock { get; set; }
public virtual Brand Brand { get; set; }
public virtual CodeProductType CodeProductType { get; set; }
public virtual ICollection<ProductImage> ProductImages { get; set; }
public virtual ICollection<ProductParam> ProductParams { get; set; }
}
public class ProductParam
{
public int Id { get; set; }
public int ProductId { get; set; }
public int CodeProductParamId { get; set; }
public string Value { get; set; }
public virtual Product Product { get; set; }
public virtual CodeProductParam CodeProductParam { get; set; }
}
and I want to get list of Products which has list of specified parameters
var prodParamCritria = new List<ProductParam>()
{
new ProductParam(){CodeProductParamId =1, Value="Black" },
new ProductParam(){CodeProductParamId =2, Value="Steal"}
};
in sql I can do it by using EXISTS clause twise
SELECT *
FROM Products p
WHERE EXISTS (
SELECT *
FROM ProductParams pp
WHERE pp.ProductId = p.ID
AND (pp.CodeProductParamId = 1 AND pp.[Value] = N'Black')
)
AND EXISTS (
SELECT *
FROM ProductParams pp
WHERE pp.ProductId = p.ID
AND pp.CodeProductParamId = 2
AND pp.[Value] = N'Steal'
)
How can i get same result by EF methods or linq

Try this:
var products= db.Products.Where(p=>p.ProductParams.Any(pp=>pp.CodeProductParamId == 1 && pp.Value == "Black") &&
p.ProductParams.Any(pp=>pp.CodeProductParamId == 2 && pp.Value == "Steal"));
Update
The problem in work with that list of ProductParam to use it as a filter is that EF doesn't know how to translate a PodructParam object to SQL, that's way if you execute a query like this:
var products2 = db.Products.Where(p => prodParamCritria.All(pp => p.ProductParams.Any(e => pp.CodeProductParamId == e.CodeProductParamId && pp.Value == e.Value)));
You will get an NotSupportedException as you comment in the answer of #BostjanKodre.
I have a solution for you but probably you will not like it. To resolve that issue you could call the ToList method before call the Where. This way you will bring all products to memory and you would work with Linq to Object instead Linq to Entities, but this is extremely inefficient because you are filtering in memory and not in DB.
var products3 = db.Products.ToList().Where(p => prodParamCritria.All(pp => p.ProductParams.Any(e => pp.CodeProductParamId == e.CodeProductParamId && pp.Value == e.Value)));
If you want filter by one criteria then this could be more simple and you are going to be able filtering using a list of a particular primitive type. If you, for example, want to filter the products only by CodeProductParamId, then you could do this:
var ids = new List<int> {1, 2};
var products = db.Products.Where(p => ids.All(i=>p.ProductParams.Any(pp=>pp.CodeProductParamId==i))).ToList();
This is because you are working with a primitive type and not with a custom object.

I suppose something like that should work
db.Product.Where(x => x.ProductParams.FirstOrDefault(y => y.CodeProductParamId == 1) != null && x.ProductParams.FirstOrDefault(y => y.CodeProductParamId == 2) != null).ToList();
or better
db.Product.Where(x => x.ProductParams.Any(y => y.CodeProductParamId == 1) && x.ProductParams.Any(y => y.CodeProductParamId == 2)).ToList();
Ok, if you need to make query on parameters in list prodParamCriteria it will look like this:
db.Product.Where(x => prodParamCritria.All(c=> x.ProductParams.Any(p=>p.CodeProductParamId == c.CodeProductParamId && p.Value== c.Value))).ToList();
I forgot that complex types cannot be used in query database, so i propose you to convert your prodParamCriteria to dictionary and use it in query
Dictionary<int, string> dctParams = prodParamCritria.ToDictionary(x => x.CodeProductParamId , y=>y.Value);
db.Product.Where(x => dctParams.All(c => x.ProductParams.Any(p=> p.CodeProductParamId == c.Key && p.Value== c.Value))).ToList();

another variation:
IEnumerable<Int32> lis = prodParamCritria.Select(x => x.CodeProductParamId).ToList();
var q = Products.Select(
x => new {
p = x,
cs = x.ProductParams.Where(y => lis.Contains(y.Id))
}
).Where(y => y.cs.Count() == lis.Count()).
ToList();
with a named class like (or maybe without, but not in linqpad)
public class daoClass {
public Product p {get; set;}
public Int32 cs {get; set;}
}
IEnumerable<Int32> lis = prodParamCritria.Select(x => x.CodeProductParamId).ToList();
var q = Products.Select(
x => new daoClass {
p = x,
cs = x.ProductParams.Where(y => lis.Contains(y.Id))
}
).Where(y => y.cs.Count() == lis.Count()).
SelectMany(y => y.p).
ToList();

Issue Related to SelectMany function in LINQ

I have two tables in Database:
PostCalculationLine
PostCaluclationLineProduct
PostCalculationLineProduct(table2) contains Foriegn key of PostCalucationLineId(table1)
In C# code I have two different Models for these two tables as follows:
public class PostCalculationLine : BaseModel
{
public long Id{ get; set; }
public string Position { get; set; }
public virtual Order Order { get; set; }
public virtual Task Task { get; set; }
//some other properties go here
public virtual IList<PostCalculationLineProduct> PostCalculationLineProducts { get; set; }
}
and
public class PostCalculationLineProduct : BaseModel
{
public long Id {get;set;}
public string Description { get; set; }
//some other properties go here
}
Now in Entityframework code, I fetch data from PostCalculationLineProduct as follows:
PostCalculationLineRepository pclr = new PostCalculationLineRepository();
DataSourceResult dsrResult = pclr.Get()
.SelectMany(p => p.PostCalculationLineProducts)
.Where(c => c.Product.ProductType.Id == 1 && c.DeletedOn == null)
.Select(c => new HourGridViewModel()
{
Id = c.Id,
Date = c.From,
EmployeeName = c.Employee != null ?c.Employee.Name:string.Empty,
Description= c.Description,
ProductName = c.Product != null?c.Product.Name :string.Empty,
From = c.From,
To = c.Till,
Quantity = c.Amount,
LinkedTo = "OrderName",
Customer ="Customer"
PostCalculationLineId = ____________
})
.ToDataSourceResult(request);
In the above query I want to get PostCalculationLineId(from Table1) marked with underLine. How can I achieve this?
Thanks

You can use this overload of SelectMany to achieve this:-
DataSourceResult dsrResult = pclr.Get()
.SelectMany(p => p.PostCalculationLineProducts,
(PostCalculationLineProductObj,PostCalculationLineObj) =>
new { PostCalculationLineProductObj,PostCalculationLineObj })
.Where(c => c.PostCalculationLineProductObj.Product.ProductType.Id == 1
&& c.PostCalculationLineProductObj.DeletedOn == null)
.Select(c => new HourGridViewModel()
{
Id = c.PostCalculationLineProductObj.Id,
Date = c.PostCalculationLineProductObj.From,
//Other Columns here
PostCalculationLineId = c.PostCalculationLineObj.Id
};
This will flatten the PostCalculationLineProducts list and returns the flattened list combined with each PostCalculationLine element.