Main Differences between ASP.NET 3.5 and ASP.NET 4.0

Main Differences between ASP.NET 3.5 and ASP.NET 4.0
As we all know, ASP.NET 3.5 has introduced with the following main new features
1) AJAX integration
2) LINQ
3) Automatic Properties
4) Lambda expressions
I hope it would be useful for everyone to know about the differences about asp.net 3.5 and its next version asp.net 4.0
Because of space consumption I’ll list only some of them here.
1) Client Data access
ASP.NET 3.5: There is no direct method to access data from client side. We can go for any of these methods
1) Pagemethods of script manager
2) ICallbackEventHandler interface
3) XMLHttphanlder component
ASP.NET 4.0: In this framework there is an inbuilt feature for this. Following are the methods to implement them.
• Client data controls
• Client templates
• Client data context
i.e we can access the data through client data view & data context objects from client side.
2) Setting Meta keyword and Meta description
Meta keywords and description are really useful for the search engine listings.
ASP.NET 3.5: It has a feature to add meta as following tag
<meta name="keywords" content="These, are, my, keywords" />
<meta name="description" content="This is the description of my page" />

ASP.NET 4.0: Here we can add the keywords and description in Page directives itself as shown below.
<%@ Page Language="C#" CodeFile="Default.aspx.cs"
Inherits="_Default"
Keywords="Keyword1,Key2,Key3,etc"
Description="description" %>

2) Enableviewstage property for each control
ASP.NET 3.5: this property has two values “True” or “false”
ASP.NET 4.0: ViewStateMode property takes an enumeration that has three values: Enabled, Disabled, and Inherit.
Here inherit is the default value for child controls of a control.
3) Setting Client IDs

Some times ClientID property creates head ach for the programmers.

ASP.NET 3.5: We have to use ClientID property to find out the id which is dynamically generated
ASP.NET 4.0: The new ClientIDMode property is introduced to minimize the issues of earlier versions of ASP.NET.
It has following values.
AutoID – Same as ASP.NET 3.5
Static – There won’t be any separate clientid generated at run time
Predictable-These are used particularly in datacontrols. Format is like clientIDrowsuffix with the clientid vlaue
Inherit- This value specifies that a control's ID generation is the same as its parent.