Hide some object fields before outputing?

Question

Is it possible to hide certain fields before outputting it?

For the sake of simplicity let's say I have User and Image one user can have multiple images.

User

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public IEnumerable<Image> Images { get; set; }
}

Output

{
    Id: "1",
    Name: "Steve"
}

Now I want to output User with images and without. Is it possible to do something like this?
_db.Users.SingleOrDefault(x => x.Id == id).Except(x => x.Images);

• This would be possible by adding [JsonIgnore] but it's not an option since I will want to output Images in some different request.
• This would be possible by outputting anonymous objects but it's not an option.
• This would be possible by creating DTO, but even so, how can I assign properties automatically from model to dto? Imagine that I have 30 fields, I don't want to assign them manually.

Answer 1

Imagine that I have 30 fields, I don't want to assign them manually.

Automapper to the rescue!

PM> Install-Package AutoMapper

DTO:

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public IEnumerable<Image> Images { get; set; }
}

public class UserInfo
{
    public int Id { get; set; }
    public string Name { get; set; }
}

Code:

Mapper.CreateMap<User, UserInfo>();

var user = new User { Id = 1, Name = "Bob" };

var userInfo = Mapper.Map<User, UserInfo>(user);

return Json(new { userInfo });