MVC5 Controller构造方法获取User为空解决方法

用如下方法获取UserId报空引用异常

public class BaseController : Controller
{
    protected SiteContext db = new SiteContext();
    protected Guid userId;
    public BaseController()
    {
        userId = Guid.Parse(User.Identity.GetUserId());
    }
}

由于Controller未初始化完成，User为空，重写初始化方法，在初始化(base.Initialize(requestContext);)完成的时候再去获取User即可

解决方法：

public class BaseController : Controller
{
    protected SiteContext db = new SiteContext();
    protected Guid userId;
    protected override void Initialize(System.Web.Routing.RequestContext requestContext)
    {
        base.Initialize(requestContext);
        if (User.Identity.IsAuthenticated)
        {
             userId =Guid.Parse(User.Identity.GetUserId());
        }
    }
}