What are the main differences between .net 1.1 and .net 2.0

ASP.NET 2.0 introduces a lot of new features. Some of this features aim to simplify the problems faced using the earlier versions and some features are introduced to provide lot of new facilities.
The most important features that are incorporated in ASP.NET 2.0 are:

(a)Master Pages
Master pages are introduced to remove one of the most important deficiencies of earlier version of ASP.NET. One thing that has become apparent in the earlier version of ASP.NET is the lack of architecture for applying a consistent look and feel. In earlier version of ASP.NET whenever a developer wants to replicate a common functionality of a web page in other pages, the most possible options he uses is creating a user control and then replicate the functionality in other pages.

ASP.NET 2.0 aims to solve this problem by introducing the concept of Master pages. First the developer needs to define a master page containing the content that he wants to appear on other pages and then use the ContentPlaceHolder controls to define the locations where the sub pages can plug in the content of their own. The he has to build the sub pages - .aspx pages – that reference the master using directives like this one:

<%@Page MasterPageFile = ~/MyMasterPage.master” %>

In addition, an application can designate a default Master Page in web.config as shown here:







(b)PreCompilation

By default, ASP.NET web pages and code files are compiled dynamically when a first request is made to the page. After the initial compilation, the compiled pages is cached; the cache is used to satisfy the subsequent requests for the same page. Even though this approach is flexible, when the page is requested for the first time, it requires a bit of extra time to compile the code. You can avoid this overhead by leveraging a new feature known as precompilation; by using this feature, you can compile an ASP.NET web site before making the web site available to the users.

(c)Sharing code in the application

In earlier version of ASP.NET, if you were to reference a reusable component from your dot net application, you had to compile the assembly and place it in the bin folder (or place it in the GAC) of the web application. But now with ASP.NET 2.0, creating a reusable component is very simple and straightforward. All you need to do is to create a component in a pre-defined subdirectory called code. Any component placed in this directory will be automatically compiled at runtime into a single assembly. This assembly is automatically referenced and will be available to all the page in the site.

(d)Themes and Skins

ASP.NET 2.0 introduces the concepts of Themes and Skins by means of which the look and feel of the web pages can be enhanced to a great extent to make them visually catchy and attractive.

A skin is a set of visual attributes applied to a control type. A theme is a collection of skins. There are a lot of predefined themes in ASP.NET 2.0. One can use it by using the following line of code:

<%@ Page Theme=”SmokeAndGlass” %>

The page directive’s Them attribute declaratively applies a theme to a page. Themes can also be applied programmatically using the page class’s Theme property

Themes and Skins in ASP.NET 2.0

When you build a Web application, it usually has a similar look and feel across all its pages. Not too many applications are designed with each page dramatically different from the next. Generally, for your applications you use similar fonts, colors, and server control styles across all the pages.

You can apply these common styles individually to each and every server control or object on each page, or you can use a new capability provided by ASP.NET 2.0 to centrally specify these styles. All pages or parts of pages in the application can then access them.

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How to apply themes
Themes can be used by a variety of methods. The following examples show you how you can define a theme named "SmokeAndGlass" in your application by different methods:

<%@ Page Theme="SmokeAndGlass" Language="C#"%>
Themes can be set programmatically under the Page_PreInit event handler. It is necessary to define them in this event handler as all the looks are applied to the server controls defined in a particular theme before the page loads. Here is how you can set themes programmatically:


protected void Page_PreInit(object sender, EventArgs e)
{
string theme = "";
if (Page.Request.Form.Count > 0)
{
theme = Page.Request["Themes"].ToString();
if (theme == "Default")
{
theme = "";
}
}
this.Theme = theme;
}