HttpContext的是空在一个叫里面的Parallel.For方法 [英] HttpContext is null in a method called inside Parallel.For

问题描述

想了很多后，发布了这个问题。这样做正常为是不是一种选择，因为我们需要做在很短的时间大量的处理。

Posting this question after trying a lot. Doing normal for is not an option because we need to do a large amount of processing in very less time.

我 GetDataFor（）这里面 HttpContext.Current 被使用。

在code是这样的：

public void SomeMethod()
{
    var context = HttpContext.Current;

    Parallel.For(0, 100, i =>
    {
        var data = GetDataFor(i, context);
    });
}

public data GetDataFor(int i, HttpContext context)
{
    Uri requestUri = null;
    if (HttpContext.Current != null)
    {
        requestUri = HttpContext.Current.Request.Url;
        sCookie = string.Format("{0}", HttpContext.Current.Request.Headers["cookie"]);
    }
    else
    {
        requestUri = context.Request.Url;
    }

    //do something
    return data;
}

一切工作正常里面罚款循环。然而，当我把它里面的 的Parallel.For 并通过 HttpContext.Current ， HttpContext.Current.Request ， HttpContext.Current.Request.Url 参数：

Everything works fine inside normal for loop. However, when I call it inside Parallel.For and pass HttpContext.Current, HttpContext.Current.Request, HttpContext.Current.Request.Url as method parameters:

HttpContext.Current无法序列化，因为它没有参数的构造函数

HttpContext.Current cannot be serialized because it does not have a parameterless constructor

传递 HttpContextBase的HttpContext = NULL 作为参数抛出：

Passing HttpContextBase httpContext = null as parameter throws:

要成为XML序列化，它自ICollection继承的类型必须在其继承层次结构的各个层次添加的实现（System.Object的）。 System.Web.HttpApplicationStateBase没有实现添加（System.Object的）。

To be XML serializable, types which inherit from ICollection must have an implementation of Add(System.Object) at all levels of their inheritance hierarchy. System.Web.HttpApplicationStateBase does not implement Add(System.Object).

试图使一个属性：

public string[] httpContextData
{
    get
    {
        string requestUrl = HttpContext.Current.Request.Url.ToString();
        string sCookie = string.Format("{0}", HttpContext.Current.Request.Headers["cookie"]);
        return new string[] { requestUrl, sCookie };
    }
}

和使用方法：

var contextData = httpContextData;

这抛出：

的System.Uri不能被序列化，因为它没有参数的构造函数

System.Uri cannot be serialized because it does not have a parameterless constructor

我做了所有该向它发送的<一个href=\"http://stackoverflow.com/questions/8109526/the-cross-thread-usage-of-httpcontext-current-property-and-related-things#comment58652454_12219078\">reference和<一个href=\"http://stackoverflow.com/questions/7851532/c-anything-wrong-with-setting-httpcontext-current-in-a-parallel-thread#comment58653226_7851532\">state但无法理解为什么问题没有解决。

I did all this to send it's reference and state but unable to understand why the problem is not solving.

我如何使用 HttpContext.Current 在的Parallel.For ？我在做什么错在这里？

How do I use HttpContext.Current inside Parallel.For? What am I doing wrong here?

顺便说一句，需要的东西有：

Btw, the needed stuff are:

HttpContext.Current.Request.Url 和 HttpContext.Current.Request.Headers [曲奇]

推荐答案

HttpContext.Current 才可用（NOT NULL）的请求处理线程<内部/ EM>。 的Parallel.For 创建多个线程，其中没有一个是可以访问 HttpContext.Current 。

HttpContext.Current is only available (not null) inside request-handling threads. Parallel.For creates multiple threads, none of which is has access to HttpContext.Current.

您必须通过

• 循环或之前分配的局部变量


• TLocal 中使用实例的Parallel.For＆LT; TLocal方式＆gt;

• local variables assigned before the loop or
• TLocal instance used in Parallel.For<TLocal>.

在任何情况下，code，如 HttpContext.Current .... 出去了。

In any event, code such as HttpContext.Current.... is out.

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