Virtual property not getting loaded after lazy loading too in ASP.NET Core

Question

Virtual property not getting loaded after lazy loading too in ASP.NET Core

.net-core asp.net-core asp.net-core-mvc c# entity-framework-core

Question

First of all I read all the answers belonged to this problem but nothing helped so far so read it once before marking it duplicate.

I have created an entity named ProjectMaster which is having a virtual property named ClientMaster. It is loading data while i was working in mvc only. But now I have migrated to CORE and here it is not getting loaded. After googling i knew that there are two thing that to be implemented for loading the virtual properties using lazy loading.

Installing the Microsoft.EntityFrameworkCore.Proxies
Call the UseLazyLoadingProxies() service in ConfigureServices inside startup

I have done both of the step and also the various alternatives. But still I am unable to load the data. Here I am sharing both the entity and congfigurationservice method.

Entity :

[Table("ProjectMaster")]
public partial class ProjectMaster
{
    [Key]
    public Guid ProjectId { get; set; }

    [Required]
    [StringLength(500)]
    public string ProjectName { get; set; }

    [Required]
    [StringLength(500)]
    public string ProjectCode { get; set; }

    public Guid ClientId { get; set; }

    public Guid CreatedBy { get; set; }

    public virtual ClientMaster ClientMaster { get; set; }
}

[Table("ClientMaster")]
public partial class ClientMaster
{
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
    public ClientMaster()
    {
        ProjectMasters = new HashSet<ProjectMaster>();
    }

    [Key]
    public Guid ClientId { get; set; }

    [Required]
    [StringLength(100)]
    public string ClientName { get; set; }

    public Guid CreatedBy { get; set; }

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
    public virtual ICollection<ProjectMaster> ProjectMasters { get; set; }
}

StartUp :

   public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<CookiePolicyOptions>(options =>
        {
            // This lambda determines whether user consent for non-essential cookies is needed for a given request.
            options.CheckConsentNeeded = context => true;
            options.MinimumSameSitePolicy = SameSiteMode.None;
        });

        services.AddEntityFrameworkProxies();
        services.AddDbContextPool<ApplicationDBContext>(options =>
        {
            options.UseSqlServer(Configuration.GetConnectionString("amcConn"));
            options.UseLazyLoadingProxies(true);
        });
        //services.AddDbContextPool<ApplicationDBContext>(options => options.UseSqlServer(Configuration.GetConnectionString("amcConn")));
       // services.AddDbContextPool<ApplicationDBContext>(options => options.UseLazyLoadingProxies().UseSqlServer(Configuration.GetConnectionString("amcConn")));


        services.AddSession();
        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

    }

Controller :

public ApiResult<List<ProjectMaster>> getallProject()
    {
        try
        {
            AMCContext _contect = new AMCContext();
            return new ApiResult<List<ProjectMaster>>
            (new ApiResultCode(ApiResultType.Success), _contect.ProjectMasters.ToList());
        }

Here all the efforts I have tried so far.

One thing to be notice here that this entity is present inside a class library project and all the necessary packages has been loaded in it.

Give me some useful suggestions if you have.

Rajan Mishra

Popular Answer

When you use lazy loading, it loads the value when you try to access that object. You can use foreach loop for this purpose like shown below :

 var foos = context.Foos.ToList();
 foreach (var Foo in foos )
 {
     var result = Foo.Id;  //This should load the value now
 }

Abhishek

View more on Stack Overflow

Tony Ngo · Accepted Answer · 7/25/2019 2:36:18 PM

The version I'm currently using

<PackageReference Include="Microsoft.EntityFrameworkCore.Proxies" Version="2.2.4" />

Using below code work for me

services.AddDbContextPool<ApplicationDbContext>(options =>
 options.UseLazyLoadingProxies()
 .UseSqlServer(configuration.GetConnectionString("DefaultConnection"));

You can remove this line of code

services.AddEntityFrameworkProxies();

Sample entities

public class Post : BaseEntity
{
    public string Title { get; set; }
    public string ShortDescription { get; set; }
    public string Content { get; set; }
    public PostStatus PostStatus { get; set; }
    public int Views { get; set; }
    public virtual User User { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
    public virtual Media Medias { get; set; }
}

public class Comment : BaseEntity
{
    public string Content { get; set; }
    public virtual Comment ParentComment { get; set; }
    public virtual Post Post { get; set; }
    public virtual User? User { get; set; }
    public CommentStatus CommentStatus { get; set; }
}

If my answer not work for you you can try something like this by using Include

   var comments = await _unitOfWork.Repository<Comment>().Query()
                .Include(x => x.User)
                .Include(c => c.Post)
                .Select(x => new CommentViewModel
                {
                    User = _mapper.Map<User, UserViewModel>(x.User),
                    Post = _mapper.Map<Post, PostViewModel>(x.Post),
                    Comment = _mapper.Map<Comment, CommentDto>(x),
                })
                .ToListAsync();

Virtual property not getting loaded after lazy loading too in ASP.NET Core

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