Blazor WebAssembly component doesn't load data from WebApi

Question

I created ASP.NET Core MVC .NET 8 application. I added simple WebApi ProductController which returns Json list of products. Then I added Blazor WebAssembly Standalone app to the solution and included one page from the Blazor app to my ASP.NET Core app. I want to implement rich UI for products with this Blazor component. To get data (products) I call the ProductController with RestSharp component. Then strange happens - the product list refreshed for a second and then disappear. If I try test data (simple mock with list of products) all works fine. I checked the ProductController WebApi it works fine, returns json data. Please help to fix this.

Blazor component file:

@inject NavigationManager NavManager

<h3>Products</h3>

@if(_viewModel == null)
{
    <p><em>Loading...</em></p>
}
else
{
    <ul>
        @foreach (var product in _viewModel.Products)
        {
            <li>@product.Name</li>
        }
    </ul>
    @if(_viewModel.Products.Count == 0)
    {
        <p><em>No products found</em></p>
    }
}

@code {
    private ProductIndexViewModel _viewModel;
    private IDataProviderFactory _dataProviderFactory;
    private IProductDataProvider _productDataProvider;

    protected override async Task OnInitializedAsync()
    {
        _dataProviderFactory = GetDataProviderFactory();
        _productDataProvider = _dataProviderFactory.CreateProductDataProvider();                
        _viewModel = await _productDataProvider.GetByGroupAndPageAsync(0, 1, 5);
    }

    private IDataProviderFactory GetDataProviderFactory()
    {
        return new RestDataProviderFactory(NavManager.BaseUri);
        //return new TestDataProviderFactory();
    }
}

RestSharp call:

        public async Task<ProductIndexViewModel> GetByGroupAndPageAsync(int productGroupId, int pageNumber, int itemsPerPage)
        {            
            string uri = $"{GetApiUri()}/GetByGroupAndPage/{productGroupId}/{pageNumber}/{itemsPerPage}";
            var request = new RestRequest(uri, Method.Get);
            var restResponse = await restClient.ExecuteGetAsync<ProductIndexViewModel>(request);
            if (restResponse.IsSuccessful)
            {
                ProductIndexViewModel viewModel = restResponse.Data;
                return viewModel;
            }
            return new ProductIndexViewModel();
        }

Answer 1

At last I fixed the bug. The problem was in my RestProductDataProvider class. It used protected field private RestClient restClient of base class RestDataProvider. If it uses local (not protected inherited) class of RestClient all works fine.