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?

Tejas Sharma

I found this MSDN forum post which suggests two solutions to your problem.

First solution (not recommended):

Find the .Net Framework 3.5 and 2.0 folder

Copy System.Web.Extensions.dll from 3.5 and System.Web.dll from 2.0 to the application folder

Add the reference to these two assemblies

Change the referenced assemblies property, setting "Copy Local" to true And build to test your application to ensure all code can work

Second solution (Use a different class / library):

The user who had posted the question claimed that Uri.EscapeUriString and How to: Serialize and Deserialize JSON Data helped him replicate the behavior of JavaScriptSerializer.

You could also try to use Json.Net. It's a third party library and pretty powerful.

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.

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