Why is System.Web.HttpUtility.UrlEncode giving namespace name doesn't exist in Visual C# 2008?

Question

I'm trying to encode a URL using the HttpUtility.UrlEncode() method, why am I getting

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

error ? I'm using Visual C# 2008, Express Edition.

The code I'm using is simplistic:

using System;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;
using System.Web;
namespace Lincr
{
    public partial class frmMain : Form
    {
        public frmMain()
        {
            InitializeComponent();
        }

        private void cmdShorten_Click(object sender, EventArgs e)
        {
            WebRequest wrURL;
            Stream objStream;
            wrURL = WebRequest.Create("http://lin.cr?l=" + System.Web.HttpUtility.UrlEncode(txtURL.Text) + "&mode=api&full=1");
            objStream = wrURL.GetResponse().GetResponseStream();
            StreamReader objSReader = new StreamReader(objStream);
            textBox1.Text = objSReader.ReadToEnd().ToString();

        }

    }
}

Answer 1

You need to include a reference to System.Web. Right-click your project in the Solution Explorer and choose Add Reference... . If you take a look at MSDN you'll see it's contained in the System.Web.dll assembly, as far as I remember, this is not referenced by default in new projects.