Saturday 9 July 2011

URLEncode Problem with .NET 4.0

Visual Studio 2010 Problem with "The name HttpUtility does not exist in the current context".

I usually use Visual Studio 2010 at work and the Express edition at home. Tonight I was knocking up quick C# windows form application to crawl some specific URL's and I required the ability to URL Encode my URI Components e.g

string url = "http//" +  System.Web.HttpUtility.UrlEncode(val);

However even though I had included:

using System.Web;

At the top of my class it was saying that HttpUtility could not be found in System.Web.

This was driving me crazy as I had another project open at the same time which was using the exact same code and it worked.

The advice I found on the web said to ensure that a reference to System.Web was added with the "Project" > "Add References" option.

However when I was searching for this DLL all I could find were System.WebServices and System.ApplicationServices which were obviously no good.

However after a lot of head scratching I went back to the main Project Properties panel and under Target Framework I had ".NET Framework 4 Client Profile" Selected.

I changed this first to .NET Framework 3.5 and then looked again for the reference and it worked!

I added it and then changed it back again to .NET Framework 4. On re-opening the project  all my problems had been solved.

Don't ask me why System.Web doesn't appear as a reference under the Client versions but it doesn't and you need to add a proper DLL reference to get to use this sort of functionality if you are doing non web based apps that require web based functionality like URL or HTML Encode etc.

I thought I would just write a few notes about this in-case anyone else experiences the same problem.


Anonymous said...

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

Woozar said...

Some much help!! Pretty much appreciate it!

Woozar said...

Some much help!! Pretty much appreciate it!

Anonymous said...

In my case changing from .Net Framework 4.0 Client Profile to just .Net Framework 4.0 (without Client Profile) solved the problem

Drowsy said...

Hi there,
Thanks, your suggestion is work for me.

SirGalad said...

Oh my God! You saved me a lot of worktime with that. Many thanks!