ASP.NET is not just the successor to Microsoft's Active Server Pages (ASP) technology whereas it is the next era of web development which was first released in January 2002 with version 1.0 of the .NET Framework. Basically, it is a server-side web application development framework designed for Web development to produce dynamic and attractive web pages. It was technologically advanced by Microsoft to allow programmers to construct dynamic web sites, web applications and web services. ASP.NET is built on the Common Language Runtime (CLR), allowing programmers to write ASP.NET code using any full featured supported .NET language such as C# or VB.NET to build web applications simply. Microsoft has created a wonderful well designed MSDN library for ASP.NET and all of the other .NET languages. It includes a full class library containing information and examples on every class, function, method, and property accessible through ASP.NET.
Featured ASP.NET is much better than Classic ASP because of following reasons:
1- Classic ASP will interpret the script for a page on every page request whereas ASP.NET will compile the code for the page once.
2- In ASP, you have to build a lot of functionality yourself while in ASP.NET many built in things are already there. You can spend fewer developer resources on building a more complex website in ASP.NET.
3- ASP uses scripting language Jscript or VBscript and .Net uses complied language which makes ASP.NET superior in performance.
4- ASP have mixed layout because it combines script code and HTML code whereas in .Net, there is a separation of code and HTML where many developers can work on the same page or file. So, ASP.NET is useful for programmers and designers.
5- ASP.NET provides support for session, application and state management while Classic ASP has no real state management; you need to write additional code to achieve this.
A directive is a special instruction or setting used by the page and user control which specifies on how ASP.NET should process the page. The most common directives are <%@ Page %> and <%@ Control %>, which can specify many attributes used by the ASP.NET page and control parsers and compilers. Directives can be located anywhere in an .aspx or .ascx file; however standard practice is to include them at the start of the file. Each directive can hold one or more attributes (paired with values) that are specific to that directive.
Below are examples for directive’s syntax:
<!-- directives -->
<%@ Page Language="C#" CodeFile="Default.aspx.cs" Inherits="Default" %>
<%@ Control Language="VB" EnableViewState="false" %>
<%@ Application Language="C#" %>
<%@ Assembly Name ="myassembly" %>
<%@ Implements Interface="interface_name" %>
<%@ namespace="System.Drawing" %>
<%@ MasterPage Language="C#" AutoEventWireup="true" CodeFile="SiteMater.master.cs" Inherits="SiteMaster" %>
<%@ OutputCache Duration="15" VaryByParam="None" %>
<%@ Reference Page ="somepage.aspx" %>
<%@ Register Src="~/footer.ascx" TagName="footer" TagPrefix="Tfooter" %>