c# - 自定义属性中的依赖注入(inject)

Question

我有一个获取 2 个参数的自定义属性，如何将此参数注入(inject) MyAttribute ？

public class MyAttribute : Attribute
{
    private readonly HttpContextAccessor _accessor;
    private readonly IUserService _userService;


    public MyAttribute(HttpContextAccessor accessor, IUserService userService)
    {
        _accessor = accessor; 
        _userService = userService;
        // ...
    }
}

Controller :

[MyAttribute()]
[Route("/action")]
public IActionResult Action()
{
   retuen View();
}

Answer 1

首先，您需要注入(inject) IHttpContextAccessor 而不是 HttpContextAccessor。

其次，服务不是有效的属性参数类型。我建议您可以使用ActionFilterAttribute 或任何其他Attribute(这取决于您的详细场景)可以转换到 ServiceFilterAttribute 或 TypeFilterAttribute。

这是一个完整的工作演示:

自定义 ActionFilterAttribute:

public class MyAttribute : ActionFilterAttribute
{
    private readonly IHttpContextAccessor _accessor;
    private readonly IUserService _userService;


    public MyAttribute(IHttpContextAccessor accessor, IUserService userService)
    {
        _accessor = accessor;
        _userService = userService;
    }
}

Controller :

//[ServiceFilter(typeof(MyAttribute))]
[TypeFilter(typeof(MyAttribute))]
public async Task<IActionResult> Index()
{          
    return View();
}

注册服务:

public void ConfigureServices(IServiceCollection services)
{
    services.AddHttpContextAccessor();
    services.AddScoped<IUserService, UserService>();
    services.AddScoped<MyAttribute>();          
}

引用:

get values from class and method attribute in middleware in asp.net core