When display data from table in ASP.NET Core 5 MVC on view model nothing display although table have multiple rows?

Question

I working on an ASP.NET Core 5 MVC app. I have a table cinimas with 5 rows.

My issue I can't display these 5 rows in my custom view model.

I try but no rows are displayed.

What I tried:

Step 1: model creation

public class Cinema : IEntityBase
{
        [Key]
        public int Id { get; set; }

        [Display(Name = "Cinema Logo")]
        [Required(ErrorMessage = "Cinema logo is required")]
        public string Logo { get; set; }

        [Display(Name = "Cinema Name")]
        [Required(ErrorMessage = "Cinema name is required")]
        public string Name { get; set; }
}

Step 2: create custom model view that will display data as view models from table:

public class CinimaViewModels
{
    public string Logo { get; set; }
    public string Name { get; set; }
}

Step 3: create service interface ICinemasService with definition for data display:

public interface ICinemasService:IEntityBaseRepository<Cinema>
{
    IQueryable<CinimaViewModels>GetAllCinimas();
}

Step 4: implement that interface in CinemasService class

public class CinemasService:EntityBaseRepository<Cinema>, ICinemasService
{
    private readonly AppDbContext _context;

    public CinemasService(AppDbContext context) : base(context)
    {
        _context = context;
    }

    public  IQueryable<CinimaViewModels> GetAllCinimas()
    {
        var cinmas = new Cinema();
         
        var response = new List<CinimaViewModels>
            {
                new CinimaViewModels 
                    {
                        Description = cinmas.Description,
                        Logo = cinmas.Logo,
                        Name = cinmas.Name
                    }
            };

        return response.AsQueryable();
    }
}

In step 4, no are rows returned although table does have 5 rows.

So how to solve this issue?

I need to return data on custom view model CinimaViewModels as IQueryable but nothing is displayed.

How to solve this issue?

Update: I checked this to return data from model it return 5 rows as below:

var cinmas2 = _context.Cinemas.ToList();

but from view model on step 4 as above nothing is returned.

Ruikai Feng · Accepted Answer · 2022-12-05 03:19:42Z

1

If you want to read the data in database,you should read from dbcontext,instead of create a new instance;

in your GetAllCinimas method,you could try as below:

public IQueryable<CinimaViewModel> GetAllCinimas()
        {
            var response = _context.Cinema.Select(x => new CinimaViewModel() { Logo = x.Logo, Name = x.Name });


            return response;


        }

You could check this document related with Data Transformations with LINQ

If you have further issue, please show more details

answered Dec 5, 2022 at 3:19

Ruikai Feng

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3 Comments

ahmed barbary Over a year ago

are there are another way without using LINQ

ahmed barbary Over a year ago

if there are another way without using linq please give me if please

Ruikai Feng Over a year ago

If you want to try with Basic SQL queries, you could check this document learn.microsoft.com/en-us/ef/core/querying/…

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