如何从抽象基本控制器访问 HttpContext？

发布于 2024-08-04 18:42:56 字数 331 浏览 4 评论 0原文

我创建了一个抽象控制器类 (ApplicationController) 来处理一些用户身份验证，但在调用代码时 HttpContext 未初始化。

public abstract class ApplicationController : Controller
{
    public ApplicationController()        
    {
        string myuser = HttpContext.User.Identity.Name; // NullReferenceException
    }
}

原文

I have created an abstract controller class (ApplicationController) for handling some user authentication, but HttpContext is not initialized when the code get called.

public abstract class ApplicationController : Controller
{
    public ApplicationController()        
    {
        string myuser = HttpContext.User.Identity.Name; // NullReferenceException
    }
}

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森林很绿却致人迷途 2024-08-11 18:42:56

Yassir 关于在抽象类中使用受保护的构造函数是正确的。但你是对的，它不能解决你的问题——HttpContext 仍然没有完全填充，所以你会得到空引用异常。

不管怎样，解决方案很简单——重写控制器的Initialize方法：

protected override void Initialize(System.Web.Routing.RequestContext requestContext)
{
    string myuser = this.User.Identity.Name;
    base.Initialize(requestContext);
}

Yassir is correct about using protected constructors in abstract classes. But you are correct that it doesn't solve your problem--the HttpContext still ain't quite populated yet so you get null reference exceptions.

Anyhow, the solution is simple--override the Initialize method of the controller:

protected override void Initialize(System.Web.Routing.RequestContext requestContext)
{
    string myuser = this.User.Identity.Name;
    base.Initialize(requestContext);
}

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耳根太软 2024-08-11 18:42:56

尝试使您的 .ctor 受到保护

public abstract class ApplicationController : Controller 
{
    protected ApplicationController()
    {
        string myuser = this.User.Identity.Name;
    } 
}

，并确保您没有错过此 using 指令：

using System.Web.Mvc;

try to make your .ctor protected

public abstract class ApplicationController : Controller 
{
    protected ApplicationController()
    {
        string myuser = this.User.Identity.Name;
    } 
}

also make sure you are not missing this using directive: