WebApi无法序列化实体框架实体

Question

I'm working on a WebApi project and I want to serialize a List<User> and send it back to the user. But it just returns [{"$id":"1"}] where User is an entity which was generated by Entity Framework database-first models classes.

Controller:

public List<User> GetAllUsers() 
{ 
   List<User> Users = Common.Framework.Persistence.PersistSvr<Business.Entity.User>
                     .GetAll().ToList(); 
  return Users; 
}

Here is the User class:

 public partial class User
 {
      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
      public User()
      {
          this.ContentLikes = new HashSet<ContentLikes>();
          this.ContentPermission = new HashSet<ContentPermission>();
          this.File = new HashSet<File>();
          this.FolderPermission = new HashSet<FolderPermission>();
          this.SiteUsers = new HashSet<SiteUsers>();
          this.UserGroup = new HashSet<UserGroup>();
      }

      public long ID { get; set; }
      public string FirstName { get; set; }
      public string LastName { get; set; }
      public string Email { get; set; }
      public string UserName { get; set; }
      public string Password { get; set; }
      public Nullable<long> DiskUsed { get; set; }
      public Nullable<long> DiskUsage { get; set; }
      public Nullable<bool> Status { get; set; }

      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
      public virtual ICollection<ContentLikes> ContentLikes { get; set; }
      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
      public virtual ICollection<ContentPermission> ContentPermission { get; set; }
      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
      public virtual ICollection<File> File { get; set; }
      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
      public virtual ICollection<FolderPermission> FolderPermission { get; set; }
      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
      public virtual ICollection<SiteUsers> SiteUsers { get; set; }
      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
      public virtual ICollection<UserGroup> UserGroup { get; set; }
 }

I have added these lines of codes to WebApiConfig.cs File.

 var json = config.Formatters.JsonFormatter;
 json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;
 config.Formatters.Remove(config.Formatters.XmlFormatter);

it just resolved double serialization. and i have my old problem. i will receive $id : "1" when i send a request to my ActionMethod.

i have learned that it's because of EntityFramework. because WebApi doesn't able to serialize an EntityFramework Entity (i think it's because of relations that exists in my Models)

so what should i do to solve it ? I don't want to rewrite them all.

Answer 1

Try this

public IHttpActionResult GetAllUsers()
        {
            try
            {
                List<User> Users = Common.Framework.Persistence.PersistSvr<Business.Entity.User>
                                   .GetAll().ToList(); 
                return Ok(Users);

            }
            catch (Exception ex)
            {
                return Content(HttpStatusCode.InternalServerError, ex.Message);

            }
        }

You will get response in users as json along with status code.