HttpUtility 在当前上下文中不存在

我在编译 C # 应用程序时遇到了这个错误，看起来像是一个小错误，但我无法避免。

我的设置是 Windows 764位.Visual-Studio 2010 C # Express B2Rel。

我添加了一个对 System 的引用。Dll 位于 C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0，但是它有一个黄色的感叹号，我仍然得到上面的错误。我还有 using System.Web的声明。

我做错了什么？

更新: 在得到指向根本原因的提示性答案后，我在谷歌上搜索了一下指向系统的位置。Dll 用于完整的框架。我没有找到这样的参考。
对于像我这样的新手来说，这个 blog 很好地总结了框架(客户端和完整框架)之间的差异。我找不到说明某个 Dll 是否在客户机框架中受支持的地方。我想 Visual Studio 的叹号应该是第一个信号..。

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最佳答案

You're probably targeting the Client Profile, in which System.Web.dll is not available.

You can target the full framework in project's Properties.

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You need to add the System.Web reference;

  1. Right click the "Reference" in the Solution Explorer
  2. Choose "Add Reference"
  3. Check the ".NET" tab is selected.
  4. Search for, and add "System.Web".
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SLaks has the right answer... but let me be a bit more specific for people, like me, who are annoyed by this and can't find it right away :

Project -> Properties -> Application -> Target Framework -> select ".Net Framework 4"

the project will then save and reload.

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I had the same problem what I did, I copied web.dll from Microsoft.NET framework, then paste in root of project, then add dll refrence to app, it worked

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Agrega System.web a las referencias del proyecto.

[Edit]

According to Google Translate, this translates to:

Add System.Web to the project references.

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In order to resolve this, Kindly go to the below path

Project-->Properties-->Application-->TargetFramework

and change the Framework to ".NET Framework 4".

Once you do this, the project will close and re-open.

This should solve the error.

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In order to resolve this, Kindly go to the below path

Project-->Properties-->Application-->TargetFramework

and change the Framework to ".NET Framework 4".

Once you do this, the project will close and re-open.

This should solve the error

(but for some reason @Karan Modi's answer does not...)

next right-click the references tab in the solution explorer and choose add reference,

choose "System.Web"

(declaring the namespace directly by "using System.Web;" doesnt seems to be enough...you have to add it to the solution explorer...i cant understand why - which is no surprise because i am a cobol programmer..

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After following the answers above , and did

Project -> Properties -> Application -> Target Framework -> select ".Net Framework 4"

It still didn't work until I went to
Project -> Add Reference
And selected System.web. And everything worked link a charm.

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It worked for by following process:

Add Reference:

system.net
system.web

also, include the namespace

using system.net
using system.web
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Adding a reference to Sysem.Web.Dll did it for me.


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