Маг-притворщик's questions

有这样的型号

public class Product // Товар
{
    public int Id { get; set; }

    public string Name { get; set; }

    public int CategoryId { get; set; }

    public ProductCategory Category { get; set; }
}

public class ProductCategory // Категория товаров
{
    public int Id { get; set; }

    public string Name { get; set; }

    public List<Product> Products { get; set; } = new List<Product>();
}

我需要大规模改变产品null类别CategoryId = 1

我正在尝试这样做

await _context.Products.Where(w => w.Id == 1)
            .ExecuteUpdateAsync(s=>s.SetProperty(u=>u.Category, u=>u.Category = null));

但我收到一个错误

An expression tree may not contain an assignment operator

我怎么解决这个问题？

在这里，我将 IRepository<Network> 服务添加到服务容器，然后该类AdminController使用它。这个实现是反模式吗локатор сервисов？

public void ConfigureServices(IServiceCollection services)
{
    ...

    services.AddTransient<IRepository<Network>, EFRepository<Network>>();

    ...
}

public class AdminController : Controller
{
    private readonly IRepository<Network> _dbContext;

    public AdminController(IRepository<Network> dbContext)
    {
        _dbContext = dbContext;
    }
}