Asp.net Core does not serialize my new type - asp.net-core

Question

Am using .net core +angular 5, and trying to return a list, but one field is null in JSON response. Am using Postman to trigger debugging and saw in VS that the field has a value coming from the DB.
Don't know why it doesn't in the JSON response.
[HttpGet("[action]")]
public IEnumerable<HikingTrail> HikingTrails()
{
var dbOptions = new DbContextOptionsBuilder<HikingTrailContext>();
dbOptions.UseSqlServer("Server = (localdb)\\mssqllocaldb; Database = HikingApp");
var dbContext = new DAO.HikingTrailContext(dbOptions.Options);
return dbContext.HikingTrails.ToList();
}
This returns:
I'm interested in the "mountainRange" field not being null. In debug window it has the right value.
{
"url": null,
"hikingTrailId": 159,
"mountainRange": null,
"name": "My custom name",
"startPoint": null,
"endPoint": null,
"trailCheckpoints": null,
"type": 2,
"dificulty": null,
"duration": "2 1/2 - 3 h",
"minDuration": "00:00:00",
"maxDuration": "00:00:00",
"seasonality": "mediu",
"equipmentLevel": null,
"trailMarking": null,
"hasTrailType": false
},
I was thinking maybe it's EF Core, and have made this 2nd try (i.e. added Include() to dbContext query):
[HttpGet("[action]")]
public IEnumerable<HikingTrail> HikingTrails()
{
var dbOptions = new DbContextOptionsBuilder<HikingTrailContext>();
dbOptions.UseSqlServer("Server = (localdb)\\mssqllocaldb; Database = HikingApp");
var dbContext = new DAO.HikingTrailContext(dbOptions.Options);
return dbContext.HikingTrails.Include( x => x.MountainRange).ToList();
}
Could not get any response in Postman.
EDIT:
public class HikingTrailContext : DbContext
{
public HikingTrailContext(DbContextOptions<HikingTrailContext> options) : base(options)
{
}
public HikingTrailContext():base(){
}
public DbSet<HikingTrail> HikingTrails { get; set; }
public DbSet<MountainRange> MountainRanges { get; set; }
public DbSet<TrailScrapingSessionInfo> TrailScrapingHistory { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
}
}
public class HikingTrail
{
[Key]
public int HikingTrailId { get; set; }
public HikingTrail() { }
public MountainRange MountainRange { get; set; }
public String Name { get; set; }
public Location StartPoint { get; set; }
public Location EndPoint { get; set; }
public List<Location> TrailCheckpoints { get; }
public TrailType Type => TrailType.Undetermined;
public String Dificulty { get; set; }
public String Duration { get; set; }
public TimeSpan MinDuration { get; set; }
public TimeSpan MaxDuration { get; set; }
public String Seasonality { get; set; }
public String EquipmentLevel { get; set; }
public String TrailMarking { get; set; }
public String URL;
public bool HasTrailType
{
get
{
return this.Type != TrailType.Undetermined;
}
}
public override bool Equals(object obj)
{
return (((HikingTrail)obj).Name == this.Name);
}
public override int GetHashCode()
{
int hash = 17;
// Suitable nullity checks etc, of course :)
hash = hash * 23 + Name.GetHashCode();
hash = hash * 23 + Type.GetHashCode();
hash = hash * 23 + StartPoint.GetHashCode();
return hash;
}
public override string ToString()
{
return Name.ToString();
}
}
EDIT :
I profiled the db on dbContext.HikingTrails.Include(x => x.MountainRange).Where(x => x.MountainRange != null).ToList(); and the generated query is OK, meaning it has a Name column for MountainRange as well.
P.S.: several fields are null, but those ones don't have data yet.

Answer 1

found one solution, Projection to an anonymous type. Also had to be careful not to have two fields with the same name of "Name"
[HttpGet("[action]")]
public dynamic HikingTrails3()
{
var dbOptions = new DbContextOptionsBuilder<HikingTrailContext>();
dbOptions.UseSqlServer("Server = (localdb)\\mssqllocaldb; Database = HikingApp");
var dbContext = new DAO.HikingTrailContext(dbOptions.Options);
var trails = dbContext.HikingTrails.Include(x => x.MountainRange).
Select( i =>new { Name= i.Name, MountainRangeName = i.MountainRange.Name, i.Duration,
i.Dificulty,i.EquipmentLevel, i.Seasonality, i.Type }).ToList();
return trails;
}