HttpUtility does not exist in the current context

I get this error when compiling a C# application. Looks like a trivial error, but I can't get around it.

My setup is Windows 7 64 bit. Visual-Studio 2010 C# express B2Rel.

I added a reference to System.Web.dll located at C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0, but it has a yellow exclamation symbol and I still get the above error. I also have the using System.Web declaration.

What am I doing wrong?


Update: After getting the prompt answer pointing me at the root cause, I searched a bit in Google to where it states that System.Web.dll is for the full framework. I did not find such a reference.
For newbies like me, this blog summarizes the difference between the frameworks (client and full) nicely. I could not find a spot that says whether a certain Dll is supported in the client framework or not. I guess the exclamation mark in Visual Studio should be the first signal...


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".

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.


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.


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..