Difference

1.Difference between trace and debug in .NET

S.No	Trace	Debug
1	This class works only when your application build defines the symbol TRACE.	This class works only when your application build defines the symbol DEBUG.
2	For tracing, you have to use Trace.WriteLine statements.	For tracing, you have to use Debug.WriteLine statements.
3	Trace class is generally used to trace the execution during deployment of the application.	You generally use debug classes at the time of development of application.
4	Trace class works in both debug mode as well as release mode.	Debug class works only in debug mode.
5	Performance analysis can be done using Trace class.	Performance analysis cannot be done using Debug class.
6	Trace runs in a thread that is different from the Main Thread.	Debug runs in the same thread in which your code executes.
7	Trace is used during Testing Phase and Optimization Phase of different releases.	Debug is used during Debugging Phase

2.Difference between ASP and ASPX

S.No	ASP	ASPX
1	The .asp is the file extension of the classic ASP page.	The .aspx is the file extension of ASP.NET page.
2	ASP stands for Active Server Pages.	ASPX is the acronym of Active Server Pages Extended.
3	The .asp file runs under the process space of inetinfo.exe, which is an IIS process space.	The .aspx file runs in a separate worker process called as aspnet_wp.exe.
4	The .asp file can execute only in platforms of Microsoft technology. It cannot run in non-Microsoft platforms like Apache Web Server.	The .aspx file can run on any platforms, be it Microsoft or not. Hence .aspx file can be executed in Apache Web Server as well.
5	The .asp file can be coded in only two languages namely VBScript and Javascript. Both these languages are client side languages.	The .aspx file can be coded using any .NET language including VB.NET, C#. Both VB.NET and C# are Server Side Languages.
6	In .asp file, the executable code can be included outside a function scope where in the function is located inside the script block marked as runat=server.	In .aspx file, the executable code cannot be included outside a function scope where in the function is located inside the script block marked as runat=server.
7	In .asp file, a function can be defined inside server side script tags.	In .aspx file, a function cannot be defined inside server side script tags.
8	In .asp file, all the directives will be placed in the page’s first line using <%@Page Language= “Jscript” %> tag.	In .aspx, the language directive must be enclosed within page directive as <%@Page Language= “VB” %>

3.Difference between thread and process

S.No	Thread	Process
1	Threads share the address space of the process that created it.	Processes have their own address.
2	Threads have direct access to the data segment of its process	Processes have their own copy of the data segment of the parent process.
3	Threads can directly communicate with other threads of its process	Processes must use interprocess communication to communicate with sibling processes.
4	Threads have almost no overhead	Processes have considerable overhead
5	New threads are easily created	New processes require duplication of the parent process.
6	Threads can exercise considerable control over threads of the same process	Processes can only exercise control over child processes
7	Changes to the main thread (cancellation, priority change, etc.) may affect the behavior of the other threads of the process	Changes to the parent process does not affect child processes.

4.Difference between ASPX and ASCX

S.No	ASPX	ASCX
1	ASP.NET Page uses the extension .aspx For eg: Default.aspx	User Control uses the extension .ascx For eg: WebUserControl.ascx.
2	ASP.NET Page begin with a Page Directive. For eg: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>	User Control begin with a Control Directive. For eg: <%@ Control Language="C#" AutoEventWireup="true" CodeFile="WebUserControl.ascx.cs" Inherits="WebUserControl" %>
3	Usercontrol code can be used in webforms	We can not use webforms in usercontrol.
4	ASP.NET Page can be viewed directly in the Browser.	User Control cannot be viewed directly in the browser. User Controls are added to WebPages and we view them by requesting a web page in our browser
5	ASP.NET page has HTML, Body or Form element.	User Control does not have a HTML, Body or Form element.

1.            What are the differences between Inline code and Code Behind Code?

S.No	Inline code	Code Behind Code
1	Its within .aspx file	Its in a external class file
2	Dynamically compiled	Compiled prior to deployment and  linked with .aspx file

2.          What are the differences between Global.asax and Web.Config?

S.No	global.asax	web.config
1	It is a class file	It is an XML file
2	There can be only one for an application	There can be many if under different sub-folders
3	Can have Application and Session events	Cannot have Application and Session events
4	Need to be recompiled when changes are made	No need to compile when changes are made

3.          What are the Differences between Server.Transfer and Response.Redirect?

S.No	Server.Transfer	Response.Redirect
1	The navigation happens on the server-side ,so client history is not updated	The navigation happens on the client-side ,so client history is updated
2	Data can be persist across the pages using Context.Item collection	Context.Items loses the persistence
3	No Round-trips	Makes a Round-trip
4	Has Good encapsulation	No

4.    What is the difference between a custom control and a user control?

S.No	User Control	Custom Control
1	Is a file with the .ascx extension	Is a file with the .dll extension
2	Can be only used with the application	Can be used in any number of applications
3	Language dependent	They are language independent, a control created in c# can be used in vb.net
4	Cannot be added to Visual studio Toolbox	Can be added to Visual studio Toolbox
5	Inherits from Server controls and easy to create	We have to develop from scratch ,  so comparatively difficult
6	Generally used for static content	Used when dynamic content is required

5.    What is the difference between Caching and Application?

S.No	Caching	Application
1	Cache have expire policy	Application does not have expire policy
2	Cache does not require explicit locking	Application require explicit locking
3	Cache has the Property of timeout, which allows us to control the duration of the Objects so cached	Application variables exist as long as the application is alive
4	Output can be cached in 4 ways, ·         Page Output Caching ·         Page Partial Caching ·         DataSource Caching ·         Data Caching	Application does not have options as like Cache object
5	It is accessible to page level to all the users	It is accessible to both page level and application level to all the users

6.    What is the difference between web farm and web garden?

S.No	Web farm	Web garden
1	A web application running on multiple servers is called a web farm.	A web application running on a single server that has multiple CPUs is called a web garden.The benefit of using this is, if one server crashes then other will work instantly.
2	For Web Garden, we have to use  in Machine.Config file.	Web Farm is implemented using techniques like Net Work Load Balancing.

Summary:

Web garden and web farms are asp.net applications that serve the purpose when the
user base of a web site increases considerably.

For Web garden/Web Farm configurations, we have to set sessionState mode to
StateServer/SQLServer in the web.config file.

7.    What is the difference between Application and Session Events?

S.No	Application Event	Session Event
1	Application events are used to initialize objects and data that we do want to make available to all the current sessions of our web application	Session events are used to initialize data that we want to keep throughout individual sessions, but that we do not want to share between sessions

8.    What is the difference between Session Cookies and Persistent Cookies?

S.No	Session Cookies	Persistent Cookies
1	Session Cookies do not have expiration date	Persistent Cookies have an expiration date. The expiration date indicates to the browser that it should write the cookie to the client’s hard drive

9.    What are the differences between Server Controls and HTML Controls?

S.No	Server Controls	HTML Controls
1	Server Controls can trigger control-specific events on the server	HTML Controls can trigger only page-level events on server (postback)
2	Data entered in a server control is maintained across requests. Server controls retain state	Data is not maintained in an HTML control. Data must be saved and restored using page-level scripts
3	The Microsoft .NET Framework provides a set of properties for each server control. Properties allows us to change the server control’s appearance and behavior within server-side code	HTML controls have HTML attributes only
4	Server controls automatically detect browser and adapt display as appropriate	We must detect browser in code or write for least common denominator

10.  What are the differences between ViewState and Hidden fields?

11.   

S.No	ViewState	Hidden fields
1	This is used for pages that will postback to itself	This is used for pages that will postback to itself or to another page
2	This is built in structure for maintaining state of a page	This is not an inbuilt structure
3	Security is more as data is hashed, compressed and encoded	Security is less when compared to ViewState

11.  What is the difference between SQL Cache Notification and SQL Cache Invalidation?

S.No	SQL Cache Notification	SQL Cache Invalidation
1	Using SQL Cache Notification, we can generate notifications when the data of a database on which a cached item depends changes	Using SQL Cache Invalidation, we can make a cached item invalid that depends on the data stored in a SQL server database, when the data in the SQL server database is changed

12.  What is the difference between absolute time expiration and sliding time expiration?

S.No	Absolute time expiration	Sliding time expiration
1	In absolute time expiration, a cached item expires after the expiration time specifies for it, irrespective of how often it is accessed	In sliding time expiration, the time for which the item is cached is each time incremented by its expiration time if it is accessed before completion of its expiration time

13.  What is the difference between adding items into cache through Add() method and Insert() method?

S.No	Cache.Add()	Cache.Insert()
1	Cache.Add() method also returns an object representing the item we have added in the cache ,besides adding the item in the cache	Cache.Insert() method adds only the item in the cache
2	It is not possible to replace an existing item in the cache using the Cache.Add() method	We can replace an existing item in the cache using the Cache.Insert() method

14.  What is the difference between page-level caching and fragment caching?

S.No	Page-level caching	Fragment caching
1	In Page-level caching, we cache a whole page	In Fragment caching, we cache parts of the web page such as a user control added to the web page

15.        What is the difference between Label control and Literal control?

S.No	Label control	Literal control
1	Final HTML code of a Label control has an HTML tag	Final HTML code of a Literal control contains only text, which is not surrounded by any HTML tag

16.          What is the difference between HyperLink control and LinkButton control?

S.No	HyperLink control	LinkButton control
1	A HyperLink control do not have Click and Command events	A LinkButton control have Click and Command events, which can be handled in the code behind file of the web page

17.        What is the difference between an HtmlInputCheckBox control and an HtmlInputRadioButton control?

S.No	HtmlInputCheckBox control	HtmlInputRadioButton control
1	We can select more than one HtmlInputCheckBox control from a group of HtmlInputCheckBox controls	We can select only a single HtmlInputRadioButton control from a group of HtmlInputRadioButton controls

18.        How a content page differs from a master page?

S.No	Content page	Master page
1	A content page does not have complete HTML source code	A master page has complete HTML source code inside its source file

19.      How will you differentiate a submaster page from a top-level master page?

S.No	Submaster page	Top-level master page
1	Like a content page, a submaster page also does not have complete HTML source code	Top-level master page has complete HTML source code inside its source file

20.        What is the difference between a page theme control and a global theme?

S.No	Page theme	Global theme
1	A page theme is stored inside a subfolder of the App_Themes folder of a web application	A global theme is stored inside the Themes folder on a web server
2	It can be applied to individual web pages of the web application	It can be applied to all the web sites on the web server

21.  What is the difference between a default skin and a named skin?

S.No	Default skin	Named skin
1	A default skin does not have a SkinId attribute	A named skin has a SkinId attribute
2	It is automatically applied to all the controls of the same type present on a web page	It is applied to a control explicitly by setting the SkinId property of the control from the Properties window

22.          Differentiate Globalization and Localization

S.No	Globalization	Localization
1	Globalization is the process of identifying the specific portion of a web application that needs to be different for different languages and isolating that portion from the core of the web application	Localization is the process of configuring a web application to be supported for a specific language or locale
2	example:  a)consider this tag in Web.Config file. It would cause the dates to be displayed in French for the web page of the folder where this Web.Config file is located. b) CultureInfo d=new CultureInfo("de-DE"); Response.Write(DateTime.Now.ToString("D",d); It would display date in long format using German culture	example:  we have 2 resource files: a)default.aspx.fr-FR.resx b)default.aspx.en-US.resx Using appropriate coding in the .aspx.cs files of a web page, the strings written in these resource files can be used to change the text of the strings dynamically.

23.        What are the differences between web.config and machine.config?

S.No	web.config	machine.config
1	This is automatically created when we create an ASP.Net web application project	This is automatically installed when we install Visual Studio. Net
2	This is also called application level configuration file	This is also called machine level configuration file
3	We can have more than one web.config file	Only one machine.config file exists on a server
4	This file inherits setting from the machine.config	This file is at the highest level in the configuration hierarchy

Difference between HttpHandler and HttpModule

S.No	HttpHandler	HttpModule
1	Meaning: An ASP.NET HTTP handler is the process (frequently referred to as the "endpoint") that runs in response to a request made to an ASP.NET Web application. The most common handler is an ASP.NET page handler that processes .aspx files. When users request an .aspx file, the request is processed by the page through the page handler. We can create our own HTTP handlers that render custom output to the browser.In order to create a Custom HTTP Handler,we need to Implement IHttpHandler interface(synchronous handler) or Implement IHttpAsyncHandler(asynchronous handler).	Meaning: An HTTP module is an assembly that is called on every request that is made to our application. HTTP modules are called as part of the ASP.NET request pipeline and have access to life-cycle events throughout the request. HTTP modules examine incoming and outgoing requests and take action based on the request.
2	When to use HTTP handlers: RSS feeds: To create an RSS feed for a Web site, we can create a handler that emits RSS-formatted XML. We can then bind a file name extension such as .rss to the custom handler. When users send a request to your site that ends in .rss, ASP.NET calls our handler to process the request. Image server: If we want a Web application to serve images in a variety of sizes, we can write a custom handler to resize images and then send them to the user as the handler’s response.	When to use HTTP modules: Security: Because we can examine incoming requests, an HTTP module can perform custom authentication or other security checks before the requested page, XML Web service, or handler is called. In Internet Information Services (IIS) 7.0 running in Integrated mode, we can extend forms authentication to all content types in an application. Statistics and logging: Because HTTP modules are called on every request, we can gather request statistics and log information in a centralized module, instead of in individual pages. Custom headers or footers: Because we can modify the outgoing response, we can insert content such as custom header information into every page or XML Web service response.
3	How to develop an ASP.NET handler: All we need is implementing IHttpHandler interface public class MyHandler :IHttpHandler { public bool IsReusable { get { return false; } } public void ProcessRequest(HttpContext context) { } }	How to develop a Http Module: All we need is implementing System.Web.IHttpModule interface. public class MyHttpModule : IHttpModule { public void Dispose() { } public void Init(HttpApplication context) { //here we have to define handler for events such as BeginRequest ,PreRequestHandlerExecute ,EndRequest,AuthorizeRequest and .... } // you need to define event handlers here }
4	Number of HTTP handler called: During the processing of an http request, only one HTTP handler will be called.	Number of HTTP module called: Whereas more than one HTTP modules may be called.
5	Processing Sequence: In the asp.net request pipe line ,http handler comes after http Module and it is the end point objects in ASP.NET pipeline.	Processing Sequence: In the asp.net request pipe line, http Module comes first.
6	What it does actually? HTTP Handler actually processes the request and produces the response	What it does actually? HTTP module can work on request before and on the response after HTTP Handler
7	HTTP Handler implement following Methods and Properties: Process Request: This method is called when processing asp.net requests. Here you can perform all the things related to processing request. IsReusable: This property is to determine whether same instance of HTTP Handler can be used to fulfill another request of same type.	Http Module implements following Methods and Properties: InIt: This method is used for implementing events of HTTP Modules in HTTPApplication object. Dispose: This method is used perform cleanup before Garbage Collector destroy everything.
8	Summary: If we need to create a request handler, for example we may want our own code to handle all .jpg image file requests like: http://mysite.com/filename.jpg, then we need to use HttpHandlers for this purpose.	Summary: If we want to modify a certain request, like we may want to perform some custom logic behind the scenes whenever user requests pages like mysite.com/default.aspx, we need to use HttpModules. We can create multiple HttpModules to filter any request.

1.Difference between .NET Application Development and Traditional Application Development

S.No	.NET Application Development	Traditional Application Development
1	Using .NET Framework, your program will be compiled into an intermediate language representation called MSIL (Microsoft Intermediate Language).	Your program will be compiled into an assembly language code that is very specific to the platform in which you are running your application.
2	MSIL code will not contain any API calls specific to any platform.	Assembly language code will contain API calls specific to the current application platform.
3	This MSIL code is then converted into machine code at runtime using CLR (Common Language Runtime).	This assembly language code is then converted into machine code.
4	Optimization is done at runtime by CLR.	Optimization is done by the compiler itself at compile time.
5	The compiler used in this process is static meaning that it checks only for syntax and the necessary semantics.	The compiler is not static. It performs both compilation as well as optimization.
6	Libraries used by your program are linked even before generating MSIL, but it is linked in an un-compiled form. This will be compiled by the compiler and it will be used by the CLR while executing the program.	Libraries used by your program are linked only after generating the machine code.
7	The program will not directly call APIs of the operating system. Instead CLR will act as a mediator. CLR will call API's of operating system and the result of execution will be returned to program.	Now the program is ready for execution by the operating system. The program will directly call APIs of the operating system.
8	Automatic memory management and garbage collection is done by CLR.	No automatic memory management or garbage collection.
9	.NET Framework Class Library provides object oriented libraries.	No object oriented principles are incorporated.

2.Difference between CSS and Themes

S.No	CSS	Themes
1	Applies to all HTML Controls	Applies to all the server controls
2	Is applied on the Client Side in the Browser	Is applied on the server rather than in the browser
3	We can apply multiple style sheets to a single page	But we cannot apply multiple themes to a single page. Only one theme we can apply for a single page.
4	The CSS supports cascading	But themes does not support cascading
5	The CSS cannot override the property values defined for a control.	But any property values defined in a theme, the theme property overrides the property values declaratively set on a control, unless we explicitly apply by using the StyleSheetTheme property.
6	Cannot be Applied through the configuration files	Can be Applied through Configuration Files.
7	Can be used directly via a reference to the css file location	All theme and Skin files should be placed in a special Asp.net folder called the “App_Themes” in order for the themes to work and behave normally.
8	Do not require any other resource like Skin files	Each theme should be associated with at least one Skin file.
9	In case of CSS you can define only style properties	But a theme can define multiple properties of a control not just style properties such as we can specify the graphics property for a control, template layout of a GridView control etc.

3.Difference between Postback and Callback

S.No	Postback	Callback
1	A Postback occurs when the data (the whole page) on the page is posted from the client to the server..ie the data is posted-back to the server, and thus the page is refreshed.	A callback is also a special kind of postback, but it is just a quick round-trip to the server to get a small set of data(normally), and thus the page is not refreshed, unlike with the postback.
2	With Asp.Net, the ViewState is refreshed when a postback is invoked.	With Asp.Net, the ViewState is not refreshed when a callback is invoked.
3	A postback occurs when a request is sent from the client to the server for the same page as the one the user is currently viewing. When a postback occurs, the entire page is refreshed and you can see the typical progression on the progress bar at the bottom of the browser.	A callback, generally used with AJAX, occurs when a request is sent from the client to the server for which the page is not refreshed, only a part of it is updated without any flickering occurring on the browser.

4.Difference between Session.Clear() and Session.Abandon()

S.No	Session.Clear()	Session.Abandon()
1	Session.Clear() just removes all values (content) from the Object. The session with the same key is still alive.It is just like giving value null to this session.	Session.Abandon() destroys the session and the Session_End event is triggered and in the next request, Session_Start will be fired.
2	Use Session.Clear(), if we want user to remain in the same session and we don not want user to relogin or reset all his session specific data.	So, if we use Session.Abandon(), we wil lose that specific session and we will get a new session key. We could use it for example when the user logs out.

1.Difference between ViewState and SessionState

S.No	ViewState	SessionState
1	View state is maintained in page level only.	Session state is maintained in session level.
2	View state of one page is not visible in another page.i.e., when user requests another page previous page data will be no longer available.	Session state value is available in all pages within a user session.i.e., The data will be no longer available if user close thebrowser or session timeout occurs.
3	View state information stored in client only.	Session state information stored in server.
4	View state persist the values of particular page in the client (browser) when post back operation done.	Session state persist the data of particular user in the server. This data available till user close the browser or session time completes.
5	View state used to persist page-instance-specific data.	Session state used to persist the user-specific data on the server side.

2.Difference between ViewState and ControlState

S.No	ViewState	ControlState
1	ViewState can be disabled	Control State cannot be disabled.
2	ViewState is implemented by using EnableViewState property of a control to true.	Control State works even when EnableViewState is off. To use Control State (for example in a custom control) we have to override OnInit method,call RegisterRequiresControlState method in OnInit method and then override the SaveControlState and LoadControlState methods.
3	ViewState is used to maintain page-level state for large data	Control State is used for small data only. eg: maintain clicked page number in a GridView even when EnableViewState is off

3.Difference between SessionState and Cookies

S.No	SessionState	Cookies
1	Session can store any type of data because the value is of datatype of "object"	Cookies can store only "string" datatype
2	These are stored at Server side	They are stored at Client side
3	Session are secured because it is stored in binary format/encrypted form and it gets decrypted at server	Cookie is non-secure since stored in text format at client side
4	Session is independent for every client i.e individual for every client	Cookies may or may not be individual for every client
5	There is no limitation on size or number of sessions to be used in an application	Due to cookies network traffic will increase.Size of cookie is limited to 40 and number of cookies to be used is restricted to 20.
6	For all conditions/situations we can use sessions	Only in few situations we can use cookies because of no security
7	We cannot disable the sessions.Sessions can be used without cookies also(by disabling cookies)	We can disable cookies
8	The disadvantage of session is that it is a burden/overhead on server	Since the value is string there is no security
9	Sessions are called as Non-Persistent cookies because its life time can be set manually	We have persistent and non-persistent cookies

Difference between ASP.Net 2.0 and ASP.Net 3.5

SNo	Feature	ASP.Net 2.0	ASP.Net 3.5
1	New Features	ASP.Net 2.0 includes the following as new features, 1.            Master Pages 2.            Profiles 3.            GridView Control	ASP.Net 3.5 includes the following as new features, 1.            ListView Control 2.            DataPager Control 3.            Nested Master Pages 4.            LinqDataSource Control
2	Multi-targeting	ASP.Net 2.0 does not support Multi-Targeting environment.	ASP.Net 3.5 supports multi-targeting. It means that we choose from a drop-down list whether to have Visual Studio 2008 build applications against the ASP.NET 2.0, 3.0, or 3.5 frameworks.
3	AJAX Support	There is no in-built support for AJAX in ASP.Net 2.0. Instead, it has to be downloaded and installed.	In ASP.Net 3.5, AJAX is integrated into the .NET Framework, thereby making the process of building intuitive cool user interfaces easier.
4	Siverlight Support	It does not support Siverlight.	It supports Siverlight.
5	Javascript Debugging	It does not provide Javascript debugging.	It provides Javascript debugging.
6	LINQ Support	It does not support LINQ.	It Supports Language Integrated Query (LINQ).

Difference between ASP.NET 3.5 and ASP.NET 4.0

S.No	ASP.NET 3.5	ASP.NET 4.0
1	Whether Client data can be directly accessed ? In ASP.NET 3.5, the data from the client side cannot be directly accessed. The client side data can only be accessed using script manager’s Page methods, interface named ICallbackEventHandler or by using the component XMLHttpHandler.	Whether Client data can be directly accessed ? In ASP.NET 4, the data from the client side can be directly accessed using client data view and client data context objects. Following methods are available in ASP.NET 4.0 to access Client data directly, 1) Client data controls 2) Client templates 3) Client data context
2	Whether we can set MetaTags (Keywords,Description) in the Page Directive? In ASP.NET 3.5, two meta tags can be used, one with name as keywords and other with name as description to record the keywords and description for SEO purpose. Please look atMetaTags for ASP.NET 3.5	Whether we can set MetaTags (Keywords,Description) in the Page Directive? The meta keywords and meta description is really useful for SEO optimization of the web page. In ASP.NET 4, the keywords and description can be included as part of page directive itself. Please look at MetaTags for ASP.NET 4.0
3	Whether ViewState can be applied at the Control level ? ASP.NET 3.5 EnableViewState property cannot be used to apply ViewState at the Control level.It is mainly used at the page level.Its default value is True and its acceptable values ae True and False.	Whether ViewState can be applied at the Control level ? In ASP.NET 4, ViewState mechanism is improved to set ViewState at the Contol level besides at the page level set by EnableViewState property in ASP.NET 3.5 .Its default value is Inherit and acceptable values areEnabled,Disabled and Inherit.
4	How ASP.NET 3.5 identifies ClientID ? In ASP.NET 3.5, ClientId property has to be used to find the dynamically generated client id.	How ASP.NET 4.0 identifies ClientID ? In ASP.NET 4, a property called ClientIDMode is newly introduced to identify and record the ClientId easily. ClientIDMode 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.  The default value of ClientIDMode for a page isPredictable. The default value of ClientIDMode for a control is Inherit. Because the default for controls isInherit, the default generation mode is Predictable.
5	Whether permanent redirection is possible or not ? There is no RedirectPermanent() method available in ASP.NET 3.5. Redirect method is less useful than the RedirectPermanent method. It will cause search engine results to be less current, and this can also impact performance because visitors will not be accessing the best URL. Redirect may be most useful for login pages or more complex situations.	Whether permanent redirection is possible or not ? ASP.Net 4.0 introduced a new URL redirection method RedirectPermanent() which avoids round trips. We can implement this as shown below: RedirectPermanent("/newpath/newpage.aspx"); RedirectPermanent returns a 301 HTTP response—it redirects permanently to another location. Search engines such as Google and Bing will change their indexes to point to the new page directly. To call RedirectPermanent you will need to get the Response object from the HttpContext. Then, you can call RedirectPermanent: if you pass false as the second parameter, you can perform further actions and avoid an exception.
6	Output Caching Enhancement: OutPut Cache in ASP.Net 3.5 has a limitation - generated content always has to be stored in memory, and on servers that are experiencing heavy traffic, the memory consumed by output caching can compete with memory demands from other portions of a Web application.	Output Caching Enhancement: ASP.NET 4 adds an extensibility point to output caching that enables you to configure one or more custom output-cache providers. Output-cache providers can use any storage mechanism to persist HTML content. This makes it possible to create custom output-cache providers for diverse persistence mechanisms, which can include local or remote disks, cloud storage, and distributed cache engines. In order to know how to implement Custom Output Caching, please refer to the following URL,
7	QueryExtender Control for filtering the data returned by EntityDataSource and LinqDataSource controls: There is no QueryExtender control available in ASP.NET 3.5 to filter the data returned by DataSource Controls( EntityDataSource and LinqDataSource).It has to explicitly use 'Where clause' in the data source.	QueryExtender Control for filtering the data returned by EntityDataSource and LinqDataSource controls: QueryExtender Control is an add-on to the DataSource Controls: EntityDataSource and LinqDataSource. QueryExtender is used to filter the data returned by these controls. As the QueryExtender control relies on LINQ, the filter is applied on the database server before the data is sent to the page, which results in very efficient operations. i.e., QueryExtender Control is intended to be used to create filters for data that is retrieved from a data source, without using an explicit Where clause in the data source. The control can be used to filter data in the markup of a Web page by using declarative syntax. Please look at QueryExtender Control in ASP.NET 4.0