You need to add System.Web to your assembly references of the project.

+++ Rick ---

>Rich I notice that HttpUtility should work after adding the System.Web namespace. I tried the sample in msdn and it did not work for me.
>this is my namespace
>

>using System;
>using System.Drawing;
>using System.Collections.Specialized;
>using System.ComponentModel;
>using System.Windows.Forms;
>using System.Data;
>using System.Net;
>using System.IO;
>using System.Text;
>using System.Web ;
>using sjSMSServiceManager.Class ;
>

>
>
>
>this is from MSDN sample. with error on compile
>

>D:\TEMP\ConsoleApplication3\Class1.cs(14): The type or namespace name 'HttpUtility' could not be found (are you missing a using directive or an assembly reference?)
>

>
>
>

>using System;
>using System.Web;
>using System.IO;
>
>   class MyNewClass
>   {
>      public static void Main()
>      {
>         String myString;
>         Console.WriteLine("Enter a string having '&' or '\"'  in it: ");
>         myString=Console.ReadLine();
>         String myEncodedString;
>         // Encode the string.
>         myEncodedString = HttpUtility.HtmlEncode(myString);
>         Console.WriteLine("HTML Encoded string is "+myEncodedString);
>         StringWriter myWriter = new StringWriter();
>         // Decode the encoded string.
>         HttpUtility.HtmlDecode(myEncodedString, myWriter);
>         Console.Write("Decoded string of the above encoded string is "+
>                        myWriter.ToString());
>      }
>   }
>

>
>Thanks rick