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()); ???????} ???}}MVC5 Controller构造方法获取User为空解决方法
原文地址：http://www.cnblogs.com/hgmyz/p/7753449.html