[c#] error CS0234: The type or namespace name 'Script' does not exist in the namespace 'System.Web'

I am trying to use JavaScriptSerializer in my application.

I initially received

Cannot find JavaScriptSerializer

and I solved it by adding:

using System.Web.Script.Serialization;

But then the sub-keyword Script is underlined with a blue line:

The type or namespace 'Script' does not exist in the namespace 'System.Web' (are you missing an assembly reference?)

So I added to the project a reference to:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\System.Web.Extensions.dll

That didn't help. I am still receiving the same blue underline with same error. The reference is marked with an exclamation mark yellow warning:

I tried the suggested solutions on this thread, but as @user781490 indicated, they didn't help in my situation.

Any idea how to resolve this?

Since JsonSerializer is deprecated in .Net 4.0+ I used http://www.newtonsoft.com/json to solve this issue.

NuGet- > Install-Package Newtonsoft.Json

I had the same. Script been underlined. I added a reference to System.Web.Extensions. Thereafter the Script was no longer underlined. Hope this helps someone.

Just Add reference to System.Web.Extensions and happy to go.

Add System.Web.Extensions as a reference to your project

For Ref.