无论HttpContextBase.Session和HttpContext.Current.Session上IRouteConstraint MVC4空 [英] Both HttpContextBase.Session and HttpContext.Current.Session are null on IRouteConstraint MVC4

问题描述

我不能在我的自定义RootConstraint类到达会议，IT'IS设置为null。我已经搜查，但未能找到解决办法。

 公共类AdminRootConstraint：IRouteConstraint
{
    公共BOOL匹配
        （
            HttpContextBase HttpContext的，
            路线路线，
            字符串参数名称，
            RouteValueDictionary值，
            routeDirection routeDirection
        ）
    {
        如果（（字符串）值[控制器] ==登录）
            返回true;        返回HttpContext.Current.Session = NULL＆放大器;！＆安培; （布尔）HttpContext.Current.Session [IsAuthorized];
    }
}
 

修改

下面是HttpContext的参数怎么看起来像在即时窗口。五月给出了个主意。

 的HttpContext
{} System.Web.HttpContextWrapper
    [System.Web.HttpContextWrapper]：{} System.Web.HttpContextWrapper
    AllErrors：空
    AllowAsyncDuringSyncStages：假的
    应用：{} System.Web.HttpApplicationStateWrapper
    ApplicationInstance：{} ASP.global_asax
    异步preloadMode：无
    缓存：{}的System.Web.Caching.Cache
    CurrentHandler：空
    CurrentNotification：ResolveRequestCache
    错误：空
    处理器：空
    IsCustomErrorEnabled：假的
    IsDebuggingEnabled：真
    IsPostNotification：真
    IsWebSocketRequest：假的
    IsWebSocketRequestUpgrading：假的
    项目：计数= 00000000
    PageInstrumentation：{} System.Web.Instrumentation.PageInstrumentationService
    previousHandler：空
    简介：空
    要求：{System.Web.Htt prequestWrapper}
    回应：{System.Web.Htt presponseWrapper}
    服务器：{} System.Web.HttpServerUtilityWrapper
    会议：空
    SkipAuthorization：假的
    ThreadAbortOnTimeout：真
    时间戳：{2013年9月14日16点52分53秒}
    跟踪：{} System.Web.TraceContext
    网友：{} System.Security.Principal.WindowsPrincipal
    WebSocketNegotiatedProtocol：空
    WebSocketRequestedProtocols：空
 

编辑2

我用 RedirectToAction 方法从同一地区的行动，而匹配方法执行两倍我追查。在firts执行过程中， routeDirection 参数设置为 System.Web.Routing.RouteDirection.UrlGeneration ，到时候会话不为空。但是当第二次执行大作， routeDirection 参数设置为 System.Web.Routing.RouteDirection.IncomingRequest 和会议为空。为什么呢？

解决方案

第一次比赛被称为是因为MVC正在建设的网址，并向它导航的用户的浏览器（通过发送HTTP 302）。这个时候你偶然有会议只是因为它在那一刻存在。

第二次比赛被称为是当请求到达浏览器。这次会议是不是present因为路由逻辑会被加载之前执行。例如。路由可能会使不需要届所有页面。

要结束，会话不在IRouteConstraint访问，不应使用。

I can't reach Session on my custom RootConstraint class, it'is set to null. I've searched but couldn't find a solution.

public class AdminRootConstraint : IRouteConstraint
{
    public bool Match
        (
            HttpContextBase httpContext,
            Route route,
            string parameterName,
            RouteValueDictionary values,
            RouteDirection routeDirection
        )
    {
        if ((string) values["controller"] == "Login")
            return true;

        return HttpContext.Current.Session != null && (bool)HttpContext.Current.Session["IsAuthorized"];
    }
}

Edit

Here is how the httpContext parameter looks like on immediate window. May gives an idea.

httpContext
{System.Web.HttpContextWrapper}
    [System.Web.HttpContextWrapper]: {System.Web.HttpContextWrapper}
    AllErrors: null
    AllowAsyncDuringSyncStages: false
    Application: {System.Web.HttpApplicationStateWrapper}
    ApplicationInstance: {ASP.global_asax}
    AsyncPreloadMode: None
    Cache: {System.Web.Caching.Cache}
    CurrentHandler: null
    CurrentNotification: ResolveRequestCache
    Error: null
    Handler: null
    IsCustomErrorEnabled: false
    IsDebuggingEnabled: true
    IsPostNotification: true
    IsWebSocketRequest: false
    IsWebSocketRequestUpgrading: false
    Items: Count = 0x00000000
    PageInstrumentation: {System.Web.Instrumentation.PageInstrumentationService}
    PreviousHandler: null
    Profile: null
    Request: {System.Web.HttpRequestWrapper}
    Response: {System.Web.HttpResponseWrapper}
    Server: {System.Web.HttpServerUtilityWrapper}
    Session: null
    SkipAuthorization: false
    ThreadAbortOnTimeout: true
    Timestamp: {14.09.2013 16:52:53}
    Trace: {System.Web.TraceContext}
    User: {System.Security.Principal.WindowsPrincipal}
    WebSocketNegotiatedProtocol: null
    WebSocketRequestedProtocols: null

Edit 2

I'm using RedirectToAction method from an action in the same area, and the Match method executes twice as I trace. In the firts execution, the routeDirection parameter is set to System.Web.Routing.RouteDirection.UrlGeneration, and that time the Session is not null. But when the second execution comes up, the routeDirection parameter is set to System.Web.Routing.RouteDirection.IncomingRequest and the session is null. Why?

解决方案

First time Match is called is because MVC is building URL to which it will navigate users's browser (by sending HTTP 302). This time you have session by accident simply because it exists in that moment.

Second time Match is called is when request comes to browser. This time session is not present because routing logic is executed before session is loaded. E.g. routing might render page that doesn't require session at all.

To conclude, session is not accessible in IRouteConstraint and should not be used.

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