My Login Script, Has C# changed?

Basically i started coding in c# in 2004 (my other question may say other things due to my brother using my computer) Has it changed or not? I know that unity's javascript is a modified version of javascript.

In my coding i have this at the top

using UnityEngine;
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Web;
using System.Web.Security;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

I know for a fact that those codes are suppose to work. What im doing is retrieving data from a mysql database but everything else is fine but this. So once again has it changed or is this c# modified.

If it is either of those if you know what it was changed/updated to please put it as an answer below. I need this to work. If you guys ask ill post the full coding to this script.

Thanks in advanced, Brennan

Yes, C# has changed quite a lot since 2004. Also, Unity uses Mono, not .NET, which has some differences and omissions, and furthermore not everything from Mono is included. You're not going to find any System.Web stuff in Unity, for example.