无法使用 VS Code 在 WebAPI、DTO、AutoMapper 和 .NET Core 中检索 EF 外键值

Question

I have a problem trying to retrieve the foreign key values from .NET Core C# RESTAPI application. I am using Code First. It's been bugging me and I cannot see what is the issue. I have a simple table that has a FK in it to a user table.

public class TripRouteDaySum
    {
        public int Id { get; set; }
        public int YearNum {get; set;}
        public int MonthNum {get; set;}
        public int DayNum {get; set;}
        public int HourNum { get; set;}
        [Column(TypeName="decimal(12,2)")]
        public Nullable<decimal> DistanceSum { get; set; }
        [Column(TypeName="decimal(12,2)")]
        public Nullable<decimal> CarbonSum { get; set; }

        public User User {get; set;}
        public Mode Mode {get; set;}
    }

Using Code First migration Produces:

SQL Datatable

So to retrieve it I set up a DTO with AutoMapper (set just to CreateMap as normal)

public class TripRouteDaySumDto
{        
    public int UserId {get; set;}
    public int ModeId {get; set;}
    public int YearNum {get; set;}
    public int MonthNum {get; set;}
    public int DayNum {get; set;}
    public int HourNum {get; set;}
    public decimal DistanceSum { get; set;}
    public decimal CarbonSum { get; set;}
}

I then run the query against this:

public IEnumerable<TripRouteDaySum> GetTripRouteDaySum(int userId, int yearNum, int monthNum, int dayNum, bool trackChanges) =>
            FindByCondition(c=> c.User.Id.Equals(userId) 
            && c.YearNum.Equals(yearNum)
            && c.MonthNum.Equals(monthNum) 
            && c.DayNum.Equals(dayNum), trackChanges)
            .ToList();

And during Info running on the server I can see that the query is recovering all relevant data.

Debug Info Trace

But when I respond in JSON I get the userId and modeId = 0 when clearly they are none zero in reality.

JSON output

Do I need to embellish mapping? Can my query be improved? Is my DTO definition wrong?

Answer 1

If I was you, I would just add the below to TripRouteDaySum .

public int UserId { get; set; }

public int ModeId { get; set; }

AutoMapper will be able to map them then because they have the same name in your entity and your DTO.

It would also make your filtering a bit easier, as you can replace

FindByCondition(c=> c.User.Id.Equals(userId)

with

FindByCondition(c=> c.UserId.Equals(userId)