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AutoMapper - Assign a value manually depending on the value of the source

I would like to assign a value manually to a DTO property in the Profile of the AutoMapper depending on the value I have in my entity.
Below you can see my code, but it doesn't work as expected because the .AfterMap is independent from the .Condition, as a matter of fact every dest.Sent is mapped with true:
.ForMember(
dest => dest.Sent,
opts => opts.Condition(src => src.Status == 2 && src.Status != 1)
)
.AfterMap((notification, dto) =>
dto.Sent = true);
My DTO
public class NotificationItemDTO
{
public long Id { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public string Type { get; set; }
public bool Sent { get; set; }
}
My Source
public class Notification
{
public long Id { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public string Type { get; set; }
public int Status { get; set; }
}
I wish to assign a value to dest.Sent which is a bool depending on src.Status which is an int. So if src.Status == 1, my dest.Sent = false, if src.Status == 2, my dest.Sent = true. Is it possible to achieve this?

You have misunderstood the usage of .Condition().
AutoMapper allows you to add conditions to properties that must be met before that property will be mapped.
Hence, from your scenario, you are trying to assign a different value to the destination based on condition but not block the mapping from source to destination by condition which is the main purpose of .Condition().
While .AfterMap() is the last action to be executed after the mapping definition logic is executed, hence the value will be overridden.
Using .MapFrom() and defining the logic to set the destination's Sent is true only when the source's Status is 2.
CreateMap<Notification, NotificationItemDTO>()
.ForMember(
dest => dest.Sent,
opts => opts.MapFrom(src => src.Status == 2)
);
Demo # .NET Fiddle

Error when using Select() instead of Include() in a query

I have the following query:
var catInclude = _db.Cat
.Where(x => x.ProvId == request.ProvId)
.Include(x => x.CatItems)
.SingleOrDefault(p => p.Id == request.ProvId
cancellationToken: cancellationToken);
As I don't want to get all properties from CatItems with Include(), I have created the following query:
var catSelect = _db.Cat
.Where(x => x.ProvId == request.ProvId)
.Select(p ==> new
{ Provider = p,
Items = p.CatItems.Select(x => new List<CatItems> { new CatItems
{ Id = x.Id, Name = x.Name, Price = x.Price } }
})})
SingleOrDefault(cancellationToken: cancellationToken);
But something is wrong in the 2nd query because here return _mapper.ProjectTo<CatDto>(cat) I get the following error:
Argument 1: cannot convert from '<anonymous type: Db.Entities.Cat Prov, System.Colletions.Generic.IEnumerable<System.Colletions.Generic.List<Models.CatItems> > Items>' to 'System.Linq.IQueryable'
Here is my CatDto:
public class CatDto
{
public int ProvId { get; set; }
public List<CatItems> CatItems { get; set; }
}
Here are my entities:
public class Prov
{
public int Id { get; set; }
public Cat Cat { get; set; }
}
public class Cat
{
public int Id { get; set; }
public int ProvId { get; set; }
public List<CatItems> CatItems { get; set; }
}
public class CatItems
{
public int Id { get; set; }
public int CatId { get; set; }
public DateTime CreatedOn { get; set; }
}
Is there a way to recreate the 2nd query and use it?

Main difference that instead of returning List of CatItems, your code returns IEnumerable<List<CatItems>> for property Items.
So, just correct your query to project to List:
var catSelect = await _db.Cat
.Where(x => x.ProvId == request.ProvId)
.Select(p => new CatDto
{
ProvId = p.ProvId,
Items = p.CatItems.Select(x => new CatItems
{
Id = x.Id,
Name = x.Name,
Price = x.Price
})
.ToList()
})
.SingleOrDefaultAsync(cancellationToken: cancellationToken);

I mean, even the exception is pretty self-explanatory. Nevertheless:
You are performing a .Select(...). It returns an Anonymous type. So, your catSelect is an anonymous type, thus the AutoMapper fails.
The quickest fix is to just cast (Cat)catSelect before mapping.
Or, you can dig deeper into how does AutoMapper play with anonymous types.

I feel like you can make most of the classes inherent Id and why is public cat CAT {get; set;} i thought you were supposed to initialize some kind of value

LINQ with dynamic group by

I have model:
public class Student
{
public string Name{ get; set; }
public DateTime BirthDate{ get; set; }
public string UniversityName{ get; set; }
public decimal Balance{ get; set; }
}
I have three bool variables:
IsName
IsBirthDate
IsUniversityName
And based on them, I need to create GroupBy. If IsBirthDate=true then
DbContext.Students.GroupBy(x => new { x.BirthDate }).Select(s => new
{
s.Key.BirthDate,
Balance = s.Sum(x => x.Balance).ToString(),
});
If IsBirthdate=true, IsUniversityName=true then
DbContext.Students.GroupBy(x => new { x.BirthDate, x.UniversityName }).Select(s => new
{
s.Key.BirthDate,
s.Key.UniversityName,
Balance = s.Sum(x => x.Balance).ToString(),
});
And other options with bool parameters.
How to generate the query dynamically with .GroupBy and .Select?

Maybe this helps you: Create a class that represents the key for your GroupBy:
public class StudentGroupingKey
{
public string Name { get; set; }
public DateTime? BirthDate{ get; set; }
public string UniversityName { get; set; }
}
If IsName is true, the Name property of the grouping key will be the value, otherwise it should have always the same value (e.g. null). In your Select method, you have to have always every property, but they will be null if the corresponding properties will be false. If it is necessary for you that these properties do not exist, you can't work with anoymous types. Maybe dynamic might be an option in that case.
DbContext.Students.GroupBy(x => new StudentGroupingKey
{
Name = IsName ? x.Name : null,
BirthDate = IsBirthDate ? x.Birthdate : null,
UniversityName = IsUniversityName ? x.UniversityName : null
}).Select(s => new
{
s.Key.BirthDate,
s.Key.Name,
s.Key.UniversityName,
Balance = s.Sum(x => x.Balance).ToString()
});

How to merge object properties of the same class together via LINQ

Say I have a class, I want to select multiple objects of it but create one unified object in the end. This is because of the requirement for the collection properties of the object to be combined.
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using Microsoft.EntityFrameworkCore.Internal;
using Nozomi.Base.Core;
namespace Nozomi.Data.Models.Currency
{
public class Currency : BaseEntityModel
{
public Currency(ICollection<Currency> currencies)
{
if (currencies.Any())
{
var firstCurr = currencies.FirstOrDefault();
if (firstCurr != null)
{
// Doesn't matter...
Id = firstCurr.Id;
CurrencyTypeId = firstCurr.Id;
CurrencyType = firstCurr.CurrencyType;
Abbrv = firstCurr.Abbrv;
Name = firstCurr.Name;
CurrencySourceId = firstCurr.CurrencySourceId;
CurrencySource = firstCurr.CurrencySource;
WalletTypeId = firstCurr.WalletTypeId;
PartialCurrencyPairs = currencies
.SelectMany(c => c.PartialCurrencyPairs)
.DefaultIfEmpty()
.ToList();
}
}
}
[Key]
public long Id { get; set; }
public long CurrencyTypeId { get; set; }
public CurrencyType CurrencyType { get; set; }
public string Abbrv { get; set; } // USD? MYR? IND?
public string Name { get; set; }
public long CurrencySourceId { get; set; }
public Source CurrencySource { get; set; }
// This will have a number if it is a crypto pair to peg to proper entities
public long WalletTypeId { get; set; } = 0;
public ICollection<PartialCurrencyPair> PartialCurrencyPairs { get; set; }
public bool IsValid()
{
return !String.IsNullOrEmpty(Abbrv) && !String.IsNullOrEmpty(Name) && CurrencyTypeId > 0 && CurrencySourceId > 0;
}
}
}
Here's what a PartialCurrencyPair is:
namespace Nozomi.Data.Models.Currency
{
/// <summary>
/// Partial currency pair.
/// </summary>
public class PartialCurrencyPair
{
public long CurrencyId { get; set; }
public long CurrencyPairId { get; set; }
public bool IsMain { get; set; } = false;
public CurrencyPair CurrencyPair { get; set; }
public Currency Currency { get; set; }
}
}
So basically, if you want to make EURUSD, you'll have to take two currencies to form a pair. A CurrencyPair is made up of two PartialCurrencyPairs. The reason why we can have many EUR or many USDs is that they come from different sources.
Here's what a CurrencyPair is:
public class CurrencyPair : BaseEntityModel
{
[Key]
public long Id { get; set; }
public CurrencyPairType CurrencyPairType { get; set; }
/// <summary>
/// Which CPC to rely on by default?
/// </summary>
public string DefaultComponent { get; set; }
public long CurrencySourceId { get; set; }
public Source CurrencySource { get; set; }
// =========== RELATIONS ============ //
public ICollection<CurrencyPairRequest> CurrencyPairRequests { get; set; }
public ICollection<WebsocketRequest> WebsocketRequests { get; set; }
public ICollection<PartialCurrencyPair> PartialCurrencyPairs { get; set; }
public bool IsValid()
{
var firstPair = PartialCurrencyPairs.First();
var lastPair = PartialCurrencyPairs.Last();
return (CurrencyPairType > 0) && (!string.IsNullOrEmpty(APIUrl))
&& (!string.IsNullOrEmpty(DefaultComponent))
&& (CurrencySourceId > 0)
&& (PartialCurrencyPairs.Count == 2)
&& (firstPair.CurrencyId != lastPair.CurrencyId)
&& (!firstPair.IsMain == lastPair.IsMain);
}
}
I have an IQueryable to combine into one single currency.
Code with comments (The comments basically tells you what I'm trying to achieve.
var query = _unitOfWork.GetRepository<Currency>()
.GetQueryable()
// Do not track the query
.AsNoTracking()
// Obtain the currency where the abbreviation equals up
.Where(c => c.Abbrv.Equals(abbreviation, StringComparison.InvariantCultureIgnoreCase)
&& c.DeletedAt == null && c.IsEnabled)
// Something here that will join the PartialCurrencyPair collection together and create one single Currency object.
.SingleOrDefault();
How do I come about it? Thank you so much in forward! Here's the
progress I've made so far and it works, but I'm pretty LINQ has a beautiful way to make this better and optimised:
var combinedCurrency = new Currency(_unitOfWork.GetRepository<Currency>()
.GetQueryable()
// Do not track the query
.AsNoTracking()
// Obtain the currency where the abbreviation equals up
.Where(c => c.Abbrv.Equals(abbreviation, StringComparison.InvariantCultureIgnoreCase)
&& c.DeletedAt == null && c.IsEnabled)
.Include(c => c.PartialCurrencyPairs)
.ThenInclude(pcp => pcp.CurrencyPair)
.ThenInclude(cp => cp.CurrencyPairRequests)
.ThenInclude(cpr => cpr.RequestComponents)
.ThenInclude(rc => rc.RequestComponentDatum)
.ThenInclude(rcd => rcd.RcdHistoricItems)
.ToList());
return new DetailedCurrencyResponse
{
Name = combinedCurrency.Name,
Abbreviation = combinedCurrency.Abbrv,
LastUpdated = combinedCurrency.PartialCurrencyPairs
.Select(pcp => pcp.CurrencyPair)
.SelectMany(cp => cp.CurrencyPairRequests)
.SelectMany(cpr => cpr.RequestComponents)
.OrderByDescending(rc => rc.ModifiedAt)
.FirstOrDefault()?
.ModifiedAt ?? DateTime.MinValue,
WeeklyAvgPrice = combinedCurrency.PartialCurrencyPairs
.Select(pcp => pcp.CurrencyPair)
.Where(cp => cp.CurrencyPairRequests
.Any(cpr => cpr.DeletedAt == null && cpr.IsEnabled))
.SelectMany(cp => cp.CurrencyPairRequests)
.Where(cpr => cpr.RequestComponents
.Any(rc => rc.DeletedAt == null && rc.IsEnabled))
.SelectMany(cpr => cpr.RequestComponents
.Where(rc =>
rc.ComponentType.Equals(ComponentType.Ask) ||
rc.ComponentType.Equals(ComponentType.Bid)))
.Select(rc => rc.RequestComponentDatum)
.SelectMany(rcd => rcd.RcdHistoricItems
.Where(rcdhi => rcdhi.CreatedAt >
DateTime.UtcNow.Subtract(TimeSpan.FromDays(7))))
.Select(rcdhi => decimal.Parse(rcdhi.Value))
.DefaultIfEmpty()
.Average(),
DailyVolume = combinedCurrency.PartialCurrencyPairs
.Select(pcp => pcp.CurrencyPair)
.Where(cp => cp.CurrencyPairRequests
.Any(cpr => cpr.DeletedAt == null && cpr.IsEnabled))
.SelectMany(cp => cp.CurrencyPairRequests)
.Where(cpr => cpr.RequestComponents
.Any(rc => rc.DeletedAt == null && rc.IsEnabled))
.SelectMany(cpr => cpr.RequestComponents
.Where(rc => rc.ComponentType.Equals(ComponentType.VOLUME)
&& rc.DeletedAt == null && rc.IsEnabled))
.Select(rc => rc.RequestComponentDatum)
.SelectMany(rcd => rcd.RcdHistoricItems
.Where(rcdhi => rcdhi.CreatedAt >
DateTime.UtcNow.Subtract(TimeSpan.FromHours(24))))
.Select(rcdhi => decimal.Parse(rcdhi.Value))
.DefaultIfEmpty()
.Sum(),
Historical = combinedCurrency.PartialCurrencyPairs
.Select(pcp => pcp.CurrencyPair)
.SelectMany(cp => cp.CurrencyPairRequests)
.SelectMany(cpr => cpr.RequestComponents)
.Where(rc => componentTypes != null
&& componentTypes.Any()
&& componentTypes.Contains(rc.ComponentType)
&& rc.RequestComponentDatum != null
&& rc.RequestComponentDatum.IsEnabled
&& rc.RequestComponentDatum.DeletedAt == null
&& rc.RequestComponentDatum.RcdHistoricItems
.Any(rcdhi => rcdhi.DeletedAt == null &&
rcdhi.IsEnabled))
.ToDictionary(rc => rc.ComponentType,
rc => rc.RequestComponentDatum
.RcdHistoricItems
.Select(rcdhi => new ComponentHistoricalDatum
{
CreatedAt = rcdhi.CreatedAt,
Value = rcdhi.Value
})
.ToList())
};
Here's the end result I want on that single object: A DetailedCurrencyResponse object.
public class DistinctiveCurrencyResponse
{
public string Name { get; set; }
public string Abbreviation { get; set; }
public DateTime LastUpdated { get; set; }
public decimal WeeklyAvgPrice { get; set; }
public decimal DailyVolume { get; set; }
}
A historical datum is basically a kvp, where the Key (ComponentType) is an enum.
public class DetailedCurrencyResponse : DistinctiveCurrencyResponse
{
public Dictionary<ComponentType, List<ComponentHistoricalDatum>> Historical { get; set; }
}
public class ComponentHistoricalDatum
{
public DateTime CreatedAt { get; set; }
public string Value { get; set; }
}

The query you have outlined will attempt to return you a single Currency object, but given you are looking for any with a given abbreviation, if multiple currency objects share an abbreviation, the SingleOrDefault could error due to multiple returns.
It sounds like you want to define a structure to represent the currency pairs. That structure is not a Currency entity, but a different data representation. These are commonly referred to as ViewModels or DTOs. Once you've defined what you want to return, you can use .Select() to populate that from the Currency and applicable abbreviations.
For instance, if I create a CurrencySummaryDto which will have the currency ID, Abbrevation, and a string containing all of the applicable pairs:
public class CurrencySummaryDto
{
public long CurrencyId { get; set; }
public string Abbreviation { get; set; }
public string Pairs { get; set;}
}
... then the query...
var currencySummary = _unitOfWork.GetRepository<Currency>()
.GetQueryable()
.AsNoTracking()
.Where(c => c.Abbrv.Equals(abbreviation, StringComparison.InvariantCultureIgnoreCase)
&& c.DeletedAt == null && c.IsEnabled)
.Select( c => new {
c.Id,
c.Abbrv,
Pairs = c.PartialCurrencyPairs.Select(pc => pc.PairName).ToList() // Get names of pairs, or select another annonymous type for multiple properties you care about...
}).ToList() // Alternatively, when intending for returning lots of data use Skip/Take for paginating or limiting resulting data.
.Select( c => new CurrencySummaryDto
{
CurrencyId = c.Id,
Abbreviation = c.Abbrv,
Pairs = string.Join(", ", c.Pairs)
}).SingleOrDefault();
This is if you want to do something like combine data from the currency pairs into something like a string. If you're happy to leave them as a collection of simplified data, then the extra anonymous type and .ToList() are not required, just select directly into the Dto structure. This example combines the data into a string where string.Join() is not supported in EF expressions so we have to get our data out into objects to hand over to Linq2Object for the final mapping.
Edit: Ok, you're requirement/example just got a whole lot more complicated with the pair structure, but you should be able to leverage this into the query rather than selecting the entire graph of entities by moving the selection of those values up into the main query... However...
Given the complexity of the data relationships, the approach I would recommend using since this would be assumed to be a read-only result, would be to construct a View in the database to flatten these averages and totals, then bind a simplified entity to this view rather than attempting to manage this with EF Linq. I believe it can be done with linq, but it will be quite onerous to look at, and a view-based summary entity would be a lot cleaner while keeping the execution of this logic to be executed in the database.

why my Null substitution is not working in automapper

I have written a programme in c# and used automapper to map.I have used Null substitution but it is not substituting the given value in result i am getting null only.please check the below code.I want my result to show 8099000078.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Automapper;
namespace Automapper
{
public class User
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Address { get; set; }
public string Mobile { get; set; }
}
public class Patient
{
public string Name { get; set; }
public string Location { get; set; }
public int age { get; set; }
public string phone { get; set; }
static void Main(string[] args)
{
User obj = new User();
obj.FirstName = "sujit";
obj.LastName = "kumar";
obj.Address = "Bangalore";
obj.Mobile = "";
AutoMapper.Mapper.CreateMap<User, Patient>().ForMember(
emp => emp.Name, map => map.MapFrom(p => p.FirstName + " " + p.LastName))
.ForMember(dest => dest.Location, source => source.MapFrom(x => x.Address))
.ForMember(dest => dest.phone, source => source.NullSubstitute("8099000078"));
var result = AutoMapper.Mapper.Map<User, Patient>(obj);
// Console.WriteLine(result.Name);
// Console.WriteLine(result.Location);
Console.WriteLine(result.phone);
Console.ReadLine();
}
}
}

You missed how null substitute works.
From AutoMapper Wiki:
Null substitution allows you to supply an alternate value for a
destination member if the source value is null anywhere along the
member chain.
In your code you didn't provide any source for phone property, therefore it doesn't have any value to check on null and it does not perform null substitution.
I made some changes in your code to make it works (see below):
void Main()
{
User obj = new User();
obj.FirstName = "sujit";
obj.LastName = "kumar";
obj.Address = "Bangalore";
obj.Mobile = null;
var config = new MapperConfiguration(cfg => cfg.CreateMap<User, Patient>()
.ForMember(emp => emp.Name, map => map.MapFrom(p => p.FirstName + " " + p.LastName))
.ForMember(dest => dest.Location, source => source.MapFrom(x => x.Address))
.ForMember(dest => dest.phone, source => source.MapFrom(x => x.Mobile))
.ForMember(dest => dest.phone, source => source.NullSubstitute("8099000078")));
var mapper = config.CreateMapper();
var result = mapper.Map<User, Patient>(obj);
result.Dump();
}
public class User
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Address { get; set; }
public string Mobile { get; set; }
}
public class Patient
{
public string Name { get; set; }
public string Location { get; set; }
public int age { get; set; }
public string phone { get; set; }
}
Here I provided a source for phone property (I mapped it from Mobile) and set the null value.

This should work -
.ForMember(dest => dest.phone, source => source.MapFrom(a => !string.IsNullOrWhiteSpace(a.Mobile) ? a.Mobile : "8099000078"));

I've not used Automapper before, but looking at your syntax it appears that 'source' would never be null because you pass it a valid obj (thus never having the NullSubstitute() return 8099000078.
I don't see where you're trying to map dest => dest.phone, source => source.Mobile.