Exception

[Giorgobiani-G]

Hello i have defined interface :

public interface IItem
    {
        [Get("item/getpagedlist")]
        Task<PagedList<ItemSlimResponse>> GetItemsPagedListAsync([Query] GetItemsPagedListQuery request, CancellationToken cancellationToken);
    }

i have implementation here:

 public class Item : IItem
    {
        public async Task<PagedList<ItemSlimResponse>> GetItemsPagedListAsync([Query] GetItemsPagedListQuery request, CancellationToken cancellationToken)
        {
            var  clinet = RestClient.For<IItem>();

            var res = await clinet.GetItemsPagedListAsync(request, cancellationToken);

            return res;
        }
    }

i have also ServiceCollectionExtensions i use RestEase.HttpClientFactory:

public static class ServiceCollectionExtensions
{
public static void AddGatewayServicesExtensions(this IServiceCollection services)
{
services.AddRestEaseClient("https://localhost:44372/api/v1");
}
}

i have controller :

[Route("api/v1/[controller]/[action]")]
[ApiController]
public class ItemController : ControllerBase
{
private readonly IItem _item;

    public ItemController(IItem item)
    {
        _item = item;
    }

    [HttpGet("")]
    public async Task<ActionResult<PagedList<ItemSlimResponse>>> GetPagedListAsync(
    [FromQuery] GetItemsPagedListQuery query, CancellationToken cancellationToken) =>
    await _item.GetItemsPagedListAsync(query, cancellationToken);
}

the problem is that, when i execute the Method it throws null reference exception ... IItem  isnt initilalized. can u tell me the reason, should i add adiitional configuration of services?

[canton7]

The point of RestEase is that you don't implement the IItem interface yourself. You write the interface, and RestEase generates an implementation for you.

That said, from the code you posted, the Item class should just be ignored.

What exact exception are you getting, and which line is throwing it?

[Giorgobiani-G]

public interface IItem
{
[Get("item/getpagedlist")]
Task<PagedList> GetItemsPagedListAsync([Query] GetItemsPagedListQuery request, CancellationToken cancellationToken);
}
this is ItemSlimResponse:
public class ItemSlimResponse
{
public long Id { get; set; }

public string? Code { get; set; }

public string? Barcode { get; set; }

public string? Name { get; set; }

public string? ItemCategoryName { get; set; }

public string? UnitOfMeasurementName { get; set; }

public string? ItemVatTypeName { get; set; }

}

[canton7]

Can you post the definition of PagedList?

Somewhere there's a class with a constructor which takes a System.Collections.Generic.IReadOnlyCollection<Syllogia.Gateway.DTO.InventoryManagement.Items.Responses.ItemSlimResponse>, Int32, Int32), and that constructor seems to be the thing throwing an NRE.

[Giorgobiani-G]

Sure here it is :

public class PagedList : PagingDetails
{
public List List { get; }

    public PagedList(IReadOnlyCollection<TItem> source, int pageNumber, int pageSize)
        : base(pageNumber, pageSize, source.Count)
    {
        List = source.Skip((pageNumber - 1) * pageSize).Take(pageSize).ToList();
    }

    private PagedList()
        : base(0, 0, 0)
    {
        List = new List<TItem>();
    }

    private PagedList(List<TItem> list, int pageNumber, int pageSize, int totalCount)
        : base(pageNumber, pageSize, totalCount)
    {
        List = list;
    }

    public static async Task<PagedList<TItem>> CreateAsync(IQueryable<TItem> source, int pageNumber, int pageSize, CancellationToken cancellationToken = default(CancellationToken))
    {
        int totalCount = await source.CountAsync(cancellationToken);
        if (totalCount <= 0)
        {
            return new PagedList<TItem>();
        }

        return new PagedList<TItem>(await source.Skip((pageNumber - 1) * pageSize).Take(pageSize).ToListAsync(cancellationToken), pageNumber, pageSize, totalCount);
    }
}

[canton7]

There we go. It looks like Json.NET is calling that first constructor, but source is null, so that's throwing a NullReferenceException.

I'm afraid that this is outside of the scope of RestEase -- Json.net is failing to deserialize the JSON which you're fetching into the model that you're giving it.

Test using a string containing your JSON, and call JsonConvert.DeserializeObject<T>(stringContainingJson), and tweak your model until this works. Once it does, then RestEase should work fine

[Giorgobiani-G]

Thank you