EF Core - 不要在查询中包含导航属性

Question

I'm having a really tough time finding guidance on how to AVOID including navigation properties in EF Core in a database-first approach. Using unmodified scaffolded web API controllers in Visual Studio, I have an entity that looks like this (simplified for example):

public partial class ProjectPhase
{
  public ProjectPhase()
  {
     Projects = new HashSet<Project>();
  }

  public int PhaseId { get; set; }
  public string PhaseName { get; set; }

  public virtual ICollection<Project> Projects { get; set; }
}

My request is the default scaffolded HTTP GET request:

// GET: api/Phases
[HttpGet]
public async Task<ActionResult<IEnumerable<ProjectPhase>>> GetPhases ()
{
  return await _context.ProjectPhases.ToListAsync();
}

The return value looks like this:

...{
  "phaseId": 1,
  "phaseName": "Pilot",
  "projects": []
},...

I want this request to NOT include projects in the returned object. How do I do this?

Answer 1

if you want to read-only an entity use AsNoTracking .

The AsNoTracking() extension method returns a new query and the returned entities will not be cached by the context (DbContext or Object Context).

[HttpGet]
public async Task<ActionResult<IEnumerable<ProjectPhase>>> GetPhases()
{
  return await _context.ProjectPhases.AsNoTracking().ToListAsync();
}

And another way to make the final object better by using a DTO class that matches the entity class and use automapper maybe for mapping.

Answer 2

For my purposes, using something like Automapper was a bit overkill. I just wanted to exclude a few navigation properties, so I just used the JsonIgnore attribute like so.

public int PhaseId { get; set; }
public string PhaseName { get; set; }

[System.Text.Json.Serialization.JsonIgnore]
public virtual ICollection<Project> Projects { get; set; }

Hope this helps someone else!