如何在Global.asax中检测请求是否为回调？ [英] How do I detect if a request is a callback in the Global.asax?

问题描述

我需要找到一种方法来检测在调用Application_BeginRequest方法时请求是否为回调。

I need to find a way to detect if a request is a callback when the Application_BeginRequest method is called.

Sub Application_BeginRequest(ByVal sender As Object, ByVal e As EventArgs)<br />
    Dim _isCallBack As Boolean = False

    ' Code to set _isCallBack is True or False Here

    If Not _isCallBack Then
        '... Some Code
    End If
End Sub

我需要知道要替换的内容 [

I need to know what to replace "[Code to set _isCallBack is True or False Here]" with.

推荐答案

这可能对您有帮助：
http://msdn.microsoft.com/en-us/magazine/cc163941.aspx

搜索单词__CALLBACKID：

This may help you: http://msdn.microsoft.com/en-us/magazine/cc163941.aspx
Search for the word __CALLBACKID:

要确定回调模式，请使用ASP.NET运行时在Request集合中查找__CALLBACKID条目。如果找到了这样的条目，则运行时将得出正在进行回调调用的结论。

我们需要这样做从无法访问Page.xxxx对象的app_code文件中。这是我最终使用的代码：

We needed to do this from within an app_code file where access to the Page.xxxx objects was not available. This is the code I ended up using:

If Not IsNothing(HttpContext.Current.Request("__CALLBACKID")) Then
    'The request is a callback
Else
    'The request is not a callback
End If

也许不是最漂亮的解决方案，但它确实可以做到。我们使用Array.IndexOf已有一段时间，但似乎有时form参数作为小写参数返回（不确定原因或方式），而Array.IndexOf是区分大小写的搜索。

Maybe not the prettiest solution, but it does the job. We were using Array.IndexOf for a while, but it seems that sometimes that form parameter arrives back as lowercase parameter (not sure why or how), and Array.IndexOf is a case sensitive search.

请小心寻找此类__XXXX请求密钥。我记得在某处读过，捷径这些元素不是一个好主意，因为它们的名称可能会在将来的.net版本中更改。请记住这一点！

Be careful looking for these kinds of __XXXX request keys. I remember reading somewhere that it's not a good idea to "shortcut" to these elements since their names could change in some future version of .net. Just keep that in mind!

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