AspQuestions.net

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This perform as a trip back to the client where the client's browser is redirected to the new

page. The user's browser history list is updated to reflect the new address.

15. Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?

Valid answers are:

A DataSet can represent an entire relational database in memory, complete with tables,

relations, and views.

A DataSet is designed to work without any continuing connection to the original data source.

Data in a DataSet is bulk-loaded, rather than being loaded on demand.

There's no concept of cursor types in a DataSet.

DataSets have no current record pointer You can use For Each loops to move through the

data.

You can store many edits in a DataSet, and write them to the original data source in a single

operation.

Though the DataSet is universal, other objects in ADO.NET come in different versions for

different data sources.

16. What is the Global.asax used for?

Ans : The Global.asax (including the Global.asax.cs file) is used to implement application and

session level events.

17. What are the Application_Start and Session_Start subroutines used for?

Ans : This is where you can set the specific variables for the Application and Session objects.

18. Can you explain what inheritance is and an example of when you might use it?

Ans : When you want to inherit (use the functionality of) another class. Example: With a base

class named Employee, a Manager class could be derived from the Employee base class.


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19. Whats an assembly?

Ans : Assemblies are the building blocks of the .NET framework.

20. Describe the difference between inline and code behind.

Ans : Inline code written along side the html in a page. Code-behind is code written in a

separate file and referenced by the .aspx page

21. Explain what a diffgram is, and a good use for one?

Ans : The DiffGram is one of the two XML formats that you can use to render DataSet object

contents to XML. A good use is reading database data to an XML file to be sent to a Web

Service.

22. Whats MSIL, and why should my developers need an appreciation of it if at all?

Ans : MSIL is the Microsoft Intermediate Language. All .NET compatible languages will get

converted to MSIL. MSIL also allows the .NET Framework to JIT compile the assembly on the

installed computer.

23. Which method do you invoke on the DataAdapter control to load your generated dataset

with data?

Ans : The Fill() method.

24. Can you edit data in the Repeater control?

Ans : No, it just reads the information from its data source.

25. Which template must you provide, in order to display data in a Repeater control?

Ans : ItemTemplate

51. Where do you add an event handler? It's the Attributesproperty, the Add function inside

that property. e.g. btnSubmit.Attributes.Add("onMouseOver","someClientCode();")


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52. What data type does the RangeValidator control support?

Integer,String and Date.

53. What are the different types of caching?

Caching is a technique widely used in computing to increase performance bykeeping frequently accessed or expensive data in memory. In context of web application,

caching is used to retain the pages or data across HTTP requests and reuse them without the

expense of recreating them. ASP.NET has 3 kinds of caching strategies Output Caching,

Fragment Caching, Data Caching.

Output Caching: Caches the dynamic output generated by a request. Some times it is useful to

cache the output of a website even for a minute, which will result in a better performance. For

caching the whole page the page should have OutputCache directive.

Fragment Caching: Caches the portion of the page generated by the request. Some times it is

not practical to cache the entire page, in such cases we can cache a portion of page

Data Caching: Caches the objects programmatically. For data caching asp.net provides a

cache object for eg: cache["States"] = dsStates;

54. What do you mean by authentication and authorization? Authentication is the process of

validating a user on the credentials (username and password) and authorization performs

after authentication. After Authentication a user will be verified for performing the various

tasks, Its access is limited it is known as authorization.

55. What are different types of directives in .NET?

@Page: Defines page-specific attributes used by the ASP.NET page parser and compiler. Can

be included only in .aspx files

@Control:Defines control-specific attributes used by the ASP.NET page parser and

compiler. Can be included only in .ascx files.


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@Import: Explicitly imports a namespace into a page or user control. The Import directive

cannot have more than one namespace attribute. To import multiple namespaces, use

multiple @Import directives.

@Implements: Indicates that the current page or user control implements the specified .NET

framework interface.

@Register: Associates aliases with namespaces and class names for concise notation in custom

server control syntax.

@Assembly: Links an assembly to the current page during compilation, making all the

assembly's classes and interfaces available for use on the page.

@OutputCache: Declaratively controls the output caching policies of an ASP.NET page or a

user control contained in a page

@Reference: Declaratively indicates that another user control or page source file should

be dynamically compiled and linked against the page in which this directive is declared.

56. How do I debug an ASP.NET application that wasn't written with Visual Studio.NET and

that doesn't use code-behind?

Start the DbgClr debugger that comes with the .NET Framework SDK, open the file containing

the code you want to debug, and set your breakpoints. Start the ASP.NET application.

Go back to DbgClr, choose Debug Processes from the Tools menu, and select aspnet_wp.exe

from the list of processes. (If aspnet_wp.exe doesn't appear in the list,check the "Show systemprocesses" box.) Click the Attach button to attach to aspnet_wp.exe and begin debugging.

Be sure to enable debugging in the ASPX file before debugging it with DbgClr. You can

enable tell ASP.NET to build debug executables by placing a

statement at the top of an ASPX file or a statement in a Web.config file.


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57. Can a user browsing my Web site read my Web.config or Global.asax files? No. The

section of Machine.config, which holds the master configuration settings

for ASP.NET, contains entries that map ASAX files, CONFIG files, and selected other file types

to an HTTP handler named HttpForbiddenHandler, which fails attempts to retrieve theassociated file. You can modify it by editing Machine.config or including an section in a local

Web.config file.

58. What's the difference between Page.RegisterClientScriptBlock and

Page.RegisterStartupScript? RegisterClientScriptBlock is for returning blocks of client-side

script containing functions. RegisterStartupScript is for returning blocks of client-script not

packaged in functions-in other words, code that's to execute when the page is loaded. The

latter positions script blocks near the end of the document so elements on the page that thescript interacts are loaded before the script runs.

59. Is it necessary to lock application state before accessing it?

Only if you're performing a multistep update and want the update to be treated as an atomic

operation. Here's an example:

Application.Lock ();

Application["ItemsSold"] = (int) Application["ItemsSold"] + 1;

Application["ItemsLeft"] = (int) Application["ItemsLeft"] - 1;

Application.UnLock ();

By locking application state before updating it and unlocking it afterwards, you ensure that

another request being processed on another thread doesn't read application state at exactly

the wrong time and see an inconsistent view of it. If I update session state, should I lock it, too?

Are concurrent accesses by multiple requests executing on multiple threads a concern with

session state? Concurrent accesses aren't an issue with session state, for two reasons. One, it's

unlikely that two requests from the same user will overlap. Two, if they do overlap, ASP.NETlocks down session state during request processing so that two threads can't touch it at once.

Session state is locked down when the HttpApplication instance that's processing the request

fires an AcquireRequestState event and unlocked when it fires a ReleaseRequestState event.


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Do ASP.NET forms authentication cookies provide any protection against replay attacks? Do

they, for example, include the client's IP address or anything else that would distinguish the

real client from an attacker?

No. If an authentication cookie is stolen, it can be used by an attacker. It's up to you to

prevent this from happening by using an encrypted communications channel (HTTPS).Authentication cookies issued as session cookies, do, however,include a time-out valid that

limits their lifetime. So a stolen session cookie can only be used in replay attacks as long as the

ticket inside the cookie is valid. The default time-out interval is 30 minutes.You can change

that by modifying the timeout attribute accompanying the element in Machine.config

or a local Web.config file. Persistent authentication cookies do not time-out and therefore are a

more serious security threat if stolen.

60. How do I send e-mail from an ASP.NET application?

MailMessage message = new MailMessage ();

message.From = ;

message.To = ;

message.Subject = "Scheduled Power Outage";

message.Body = "Our servers will be down tonight.";

SmtpMail.SmtpServer = "localhost";

SmtpMail.Send (message);

MailMessage and SmtpMail are classes defined in the .NET Framework Class Library's

System.Web.Mail namespace. Due to a security change made to ASP.NET just before it

shipped, you need to set SmtpMail's SmtpServer property to "localhost" even though

"localhost" is the default. In addition, you must use the IIS configuration applet to enable

localhost (127.0.0.1) to relay messages through the local SMTP service.

61. What are VSDISCO files? VSDISCO files are DISCO files that support dynamic discovery of

Web services. If you place the following VSDISCO file in a directory on your Web server, for

example, it returns references to all ASMX and DISCO files in the host directory and any

subdirectories not noted in elements:


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xmlns="urn:schemas-dynamicdiscovery:disco.2000-03-17">

62. How does dynamic discovery work? ASP.NET maps the file name extension VSDISCO to

an HTTP handler that scans the host directory and subdirectories for ASMX and DISCO files

and returns a dynamically generated DISCO document. A client who requests a VSDISCO file

gets back what appears to be a static DISCO document.

Note that VSDISCO files are disabled in the release version of ASP.NET. You can reenable

them by uncommenting the line in the section of Machine.config that maps

*.vsdisco to System.Web.Services.Discovery.DiscoveryRequestHandler and granting the

ASPNET user account permission to read the IIS metabase. However, Microsoft is actively

discouraging the use of VSDISCO files because they could represent a threat to Web server

security.

63. Is it possible to prevent a browser from caching an ASPX page? Just call SetNoStore on the

HttpCachePolicy object exposed through the Response object's Cache property, as

demonstrated here:


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SetNoStore works by returning a Cache-Control: private, no-store header in the HTTP

response. In this example, it prevents caching of a Web page that shows the current time.

64. What does AspCompat="true" mean and when should I use it?

AspCompat is an aid in migrating ASP pages to ASPX pages. It defaults to false but should beset to true in any ASPX file that creates apartment-threaded COM objects--that is, COM objects

registered ThreadingModel=Apartment. That includes all COM objects written with Visual

Basic 6.0. AspCompat should also be set to true (regardless of threading model) if the page

creates COM objects that access intrinsic ASP objects such as Request and Response. The

following directive sets AspCompat to true:

Setting AspCompat to true does two things. First, it makes intrinsic ASP objects available tothe COM components by placing unmanaged wrappers around the equivalent ASP.NET

objects. Second, it improves the performance of calls that the page places to apartment-

threaded COM objects by ensuring that the page (actually, the thread that processes the

request for the page) and the COM objects it creates share an apartment. AspCompat="true"

forces ASP.NET request threads into single-threaded apartments (STAs). If those threads

create COM objects marked ThreadingModel=Apartment, then the objects are created in the

same STAs as the threads that created them. Without AspCompat="true," request threads run

in a multithreaded apartment (MTA) and each call to an STA-based COM object incurs aperformance hit when it's marshaled across apartment boundaries.

Do not set AspCompat to true if your page uses no COM objects or if it uses COM objects that

don't access ASP intrinsic objects and that are registered ThreadingModel=Free or

ThreadingModel=Both.

65. Explain the differences between Server-side and Client-side code?

Server side scripting means that all the script will be executed by the server and interpreted

as needed. ASP doesn't have some of the functionality like sockets, uploading, etc. For these

you have to make a custom components usually in VB or VC++. Client side scripting means

that the script will be executed immediately in the browser such as form field validation, clock,

email validation, etc. Client side scripting is usually done in VBScript or JavaScript. Download

time, browser compatibility, and visible code - since JavaScript and VBScript code is included


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in the HTML page, then anyone can see the code by viewing the page source. Also a possible

security hazards for the client computer.

66. What type of code (server or client) is found in a Code-Behind class?

C#

67. Should validation (did the user enter a real date) occur server-side or client-side? Why?

Client-side validation because there is no need to request a server side date when you could

obtain a date from the client machine.

68. What are ASP.NET Web Forms? How is this technology different than what is available

though ASP?

Web Forms are the heart and soul of ASP.NET. Web Forms are the User Interface (UI) elements

that give your Web applications their look and feel. Web Forms are similar to Windows Formsin that they provide properties, methods, and events for the controls that are placed onto

them. However, these UI elements render themselves in the appropriate markup language

required by the request, e.g. HTML. If you use Microsoft Visual Studio .NET, you will also get

the familiar drag-and-drop interface used to create your UI for your Web application.

69. What is the difference between Server.Transfer and Response.Redirect? Why would I

choose one over the other?

In earlier versions of IIS, if we wanted to send a user to a new Web page, the only option we

had was Response.Redirect. While this method does accomplish our goal, it has several

important drawbacks. The biggest problem is that this method causes each page to be treated

as a separate transaction. Besides making it difficult to maintain your transactional integrity,

Response.Redirect introduces some additional headaches. First, it prevents good encapsulation

of code. Second, you lose access to all of the properties in the Request object. Sure, there are

workarounds, but they're difficult. Finally, Response.Redirect necessitates a round trip to the

client, which, on high-volume sites, causes scalability problems.

As you might suspect, Server.Transfer fixes all of these problems. It does this by performing

the transfer on the server without requiring a roundtrip to the client.

70. How can you provide an alternating color scheme in a Repeater control?

AlternatingItemTemplate Like the ItemTemplate element, but rendered for every other row

(alternating items) in the Repeater control. You can specify a different appearance for the

AlternatingItemTemplate element by setting its style properties.


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ItemTemplate

72. What event handlers can I include in Global.asax?

Application_Start,Application_End, Application_AcquireRequestState,Application_AuthenticateRequest, Application_AuthorizeRequest, Application_BeginRequest,

Application_Disposed, Application_EndRequest, Application_Error,

Application_PostRequestHandlerExecute, Application_PreRequestHandlerExecute,

Application_PreSendRequestContent, Application_PreSendRequestHeaders,

Application_ReleaseRequestState, Application_ResolveRequestCache,

Application_UpdateRequestCache, Session_Start,Session_End

You can optionally include "On" in any of method names. For example, you can name a

BeginRequest event handler.Application_BeginRequest or Application_OnBeginRequest.You

can also include event handlers in Global.asax for events fired by custom HTTP modules.Note

that not all of the event handlers make sense for Web Services (they're designed for ASP.NET

applications in general, whereas .NET XML Web Services are specialized instances of an

ASP.NET app). For example, the Application_AuthenticateRequest and

Application_AuthorizeRequest events are designed to be used with ASP.NET Forms

authentication.

73. What is different b/w webconfig.xml & Machineconfig.xml

Web.config & machine.config both are configuration files.Web.config contains settings specificto an application where as machine.config contains settings to a computer. The Configuration

system first searches settings in machine.config file & then looks in application configuration

files.Web.config, can appear in multiple directories on an ASP.NET Web application server.

Each Web.config file applies configuration settings to its own directory and all child directories

below it. There is only Machine.config file on a web server.

If I'm developing an application that must accomodate multiple security levels though secure

login and my ASP.NET web appplication is spanned across three web-servers (using round-

robbin load balancing) what would be the best approach to maintain login-in state for the

users?

Use the state server or store the state in the database. This can be easily done through simple

setting change in the web.config.


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StateConnectionString="tcpip=127.0.0.1:42424"

sqlConnectionString="data source=127.0.0.1; user id=sa; password="

cookieless="false"

timeout="30"

/>

You can specify mode as stateserver or sqlserver.

Where would you use an iHTTPModule, and what are the limitations of any approach you

might take in implementing one

"One of ASP.NET's most useful features is the extensibility of the HTTP pipeline, the path that

data takes between client and server. You can use them to extend your ASP.NET applications

by adding pre- and post-processing to each HTTP request coming into your application. For

example, if you wanted custom authentication facilities for your application, the best technique

would be to intercept the request when it comes in and process the request in a custom HTTP

module.

74. How do you turn off cookies for one page in your site?

Since no Page Level directive is present, I am afraid that cant be done.

75. How do you create a permanent cookie?

Permanent cookies are available until a specified expiration date, and are stored on the hard

disk.So Set the 'Expires' property any value greater than DataTime.MinValue with respect to

the current datetime. If u want the cookie which never expires set its Expires property equal to

DateTime.maxValue.

76. Which method do you use to redirect the user to another page without performing a round

trip to the client?

Server.Transfer and Server.Execute

77. What property do you have to set to tell the grid which page to go to when using the Pagerobject?

CurrentPageIndex

78. Should validation (did the user enter a real date) occur server-side or client-side? Why? It

should occur both at client-side and Server side.By using expression validator control with the


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specified expression ie.. the regular expression provides the facility of only validatating the

date specified is in the correct format or not. But for checking the date where it is the real data

or not should be done at the server side, by getting the system date ranges and checking the

date whether it is in between that range or not.

79. What does the "EnableViewState" property do? Why would I want it on or off? Enable

ViewState turns on the automatic state management feature that enables server controls to re-

populate their values on a round trip without requiring you to write any code. This feature is

not free however, since the state of a control is passed to and from the server in a hidden form

field. You should be aware of when ViewState is helping you and when it is not. For example,

if you are binding a control to data on every round trip, then you do not need the control to

maintain it's view state, since you will wipe out any re-populated data in any case. ViewState

is enabled for all server controls by default. To disable it, set the EnableViewState property of

the control to false.

80. What is the difference between Server.Transfer and Response.Redirect? Why would I

choose one over the other? Server.Transfer() : client is shown as it is on the requesting page

only, but the all the content is of the requested page. Data can be persist accros the pages using

Context.Item collection, which is one of the best way to transfer data from one page to another

keeping the page state alive.

Response.Dedirect() :client know the physical location (page name and query string as well).Context.Items loses the persisitance when nevigate to destination page. In earlier versions of

IIS, if we wanted to send a user to a new Web page, the only option we had was

Response.Redirect. While this method does accomplish our goal, it has several important

drawbacks. The biggest problem is that this method causes each page to be treated as a

separate transaction. Besides making it difficult to maintain your transactional integrity,


of code. Second, you lose access to all of the properties in the Request object. Sure, there are

workarounds, but they're difficult. Finally, Response.Redirect necessitates a round trip to the

client, which, on high-volume sites, causes scalability problems. As you might suspect,

Server.Transfer fixes all of these problems. It does this by performing the transfer on the server

without requiring a roundtrip to the client.


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81. Can you give an example of when it would be appropriate to use a web service as opposed

to a non-serviced .NET component?

Communicating through a Firewall When building a distributed application with100s/1000s of users spread over multiple locations, there is always the problem of

communicating between client and server because of firewalls and proxy servers.

Exposing your middle tier components as Web Services and invoking the directly from

a Windows UI is a very valid option.

Application Integration When integrating applications written in various languages

and running on disparate systems. Or even applications running on the same platform

that have been written by separate vendors.

Business-to-Business Integration This is an enabler for B2B intergtation which

allows one to expose vital business processes to authorized supplier and customers.

An example would be exposing electronic ordering and invoicing, allowing customers

to send you purchase orders and suppliers to send you invoices electronically.

Software Reuse This takes place at multiple levels. Code Reuse at the Source code

level or binary componet-based resuse. The limiting factor here is that you can reuse

the code but not the data behind it. Webservice overcome this limitation. A scenario

could be when you are building an app that aggregates the functionality of serveral

other Applicatons. Each of these functions could be performed by individual apps, but

there is value in perhaps combining the the multiple apps to present a unifiend view

in a Portal or Intranet.

When not to use Web Services: Single machine Applicatons When the apps are

running on the same machine and need to communicate with each other use a native

API. You also have the options of using component technologies such as COM or .NET

Componets as there is very little overhead.

Homogeneous Applications on a LAN If you have Win32 or Winforms apps that

want to communicate to their server counterpart. It is much more efficient to use

DCOM in the case of Win32 apps and .NET Remoting in the case of .NET Apps


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82. Can you give an example of what might be best suited to place in the Application_Start and

Session_Start subroutines?

The Application_Start event is guaranteed to occur only once throughout the lifetime of the

application. It's a good place to initialize global variables. For example, you might want to

retrieve a list of products from a database table and place the list in application state or theCache object. SessionStateModule exposes both Session_Start and Session_End events.

83. What are the advantages and disadvantages of viewstate?

The primary advantages of the ViewState feature in ASP.NET are:

1. Simplicity. There is no need to write possibly complex code to store form data between page

submissions.

2. Flexibility. It is possible to enable, configure, and disable ViewState on a control-by-control

basis, choosing to persist the values of some fields but not others.

There are, however a few disadvantages that are worth pointing out:

1. Does not track across pages. ViewState information does not automatically transfer from

page to page. With the session

approach, values can be stored in the session and accessed from other pages. This is not

possible with ViewState, so storing

data into the session must be done explicitly.

2. ViewState is not suitable for transferring data for back-end systems. That is, data still has to

be transferred to the back

end using some form of data object.

84. Describe session handling in a webfarm, how does it work and what are the limits?

ASP.NET Session supports storing of session data in 3 ways, i] in In-Process ( in the same

memory that ASP.NET uses) , ii] out-of-process using Windows NT Service )in separate

memory from ASP.NET ) or iii] in SQL Server (persistent storage). Both the Windows Serviceand SQL Server solution support a webfarm scenario where all the web-servers can be

configured to share common session state store.

1. Windows Service : We can start this service by Start | Control Panel | Administrative Tools


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| Services | . In that we service names ASP.NET State Service. We can start or stop service by

manually or configure to start automatically. Then we have to configure our web.config file

Here ASP.Net Session is directed to use Windows Service for state management on local server

(address : 127.0.0.1 is TCP/IP loop-back address). The default port is 42424. we can configure

to any port but for that we have to manually edit the registry.

Follow these simple steps

- In a webfarm make sure you have the same config file in all your web servers.

- Also make sure your objects are serializable.

- For session state to be maintained across different web servers in the webfarm, the

application path of the web-site in the IIS Metabase should be identical in all the web-servers

in the webfarm.


You have to use the ItemTemplate to Display data. Syntax is as follows,

< ItemTemplate >

< div class =rItem >< img src=images/ hspace=10 />

< b >

< /div >

< ItemTemplate >


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How can you provide an alternating color scheme in a Repeater control?

Using the AlternatintItemTemplate

86. What property must you set, and what method must you call in your code, in order to bind

the data from some data source to the Repeater control? Set the DataMember property to thename of the table to bind to. (If this property is not set, by default the first table in the dataset is

used.) DataBind method, use this method to bind data from a source to a server control. This

method is commonly used after retrieving a data set through a database query.

87. What method do you use to explicitly kill a user s session?

You can dump (Kill) the session yourself by calling the method Session.Abandon.

ASP.NET automatically deletes a user's Session object, dumping its contents, after it has been

idle for a configurable timeout interval. This interval, in minutes, is set in thesection of the web.config file. The default is 20 minutes.

88. How do you turn off cookies for one page in your site?

Use Cookie.Discard property, Gets or sets the discard flag set by the server. When true, this

property instructs the client application not to save the Cookie on the user's hard disk when a

session ends.

89. Which two properties are on every validation control?

We have two common properties for every validation controls

1. Control to Validate,

2. Error Message.

90. What tags do you need to add within the asp:datagrid tags to bind columns manually?

< asp:DataGrid id="dgCart" AutoGenerateColumns="False" CellPadding="4" Width="448px"

runat="server" >

< Columns >

< asp:ButtonColumn HeaderText="SELECT" Text="SELECT" CommandName="select" >

< asp:BoundColumn DataField="ProductId" HeaderText="Product ID" >

< asp:BoundColumn DataField="ProductName" HeaderText="Product Name" >


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/asp:BoundColumn >

< asp:BoundColumn DataField="UnitPrice" HeaderText="UnitPrice" >

< /Columns >

< /asp:DataGrid >

91. How do you create a permanent cookie? Permanent cookies are the ones that are most

useful. Permanent cookies are available until a specified expiration date, and are stored on the

hard disk. The location of cookies differs with each browser, but this doesnt matter, as this is

all handled by your browser and the server. If you want to create a permanent cookie called

Name with a value of Nigel, which expires in one month, youd use the following code

Response.Cookies ("Name") = "Nigel" Response.Cookies ("Name"). Expires = DateAdd ("m", 1,

Now ())

92. What tag do you use to add a hyperlink column to the DataGrid?

< asp:HyperLinkColumn >

93. Which method do you use to redirect the user to another page without performing a round

trip to the client?

Server.transfer

94. What is the transport protocol you use to call a Web service SOAP ?

HTTP Protocol

95. Explain role based security ? Role Based Security lets you identify groups of users to allow

or deny based on their role in the organization.In Windows NT and Windows XP, roles map to

names used to identify user groups. Windows defines several built-in groups, including

Administrators, Users, and Guests.To allow or deny access to certain groups of users, add the

element to the authorization list in your Web application's Web.config file.e.g.

< authorization >

< allow roles="Domain Name\Administrators" / > < !-- Allow Administrators in domain. -->

< deny users="*" / > < !-- Deny anyone else. -- >

< /authorization >


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96. How do you register JavaScript for webcontrols ?

You can register javascript for controls using Attribtues.

Add(scriptname,scripttext) method.

97. When do you set "" ?Identity is a webconfig declaration under System.web, which helps to control the application

Identity of the web applicaton. Which can be at any

level(Machine,Site,application,subdirectory,or page), attribute impersonate with "true" as

value specifies that client impersonation is used.

98. What are different templates available in Repeater,DataList and Datagrid ? Templates

enable one to apply complicated formatting to each of the items displayed by a

control.Repeater control supports five types of templates.HeaderTemplate controls how the

header of the repeater control is formatted.ItemTemplate controls the formatting of each item

displayed.AlternatingItemTemplate controls how alternate items are formatted and the

SeparatorTemplate displays a separator between each item displyed.FooterTemplate is used

for controlling how the footer of the repeater control is formatted.The DataList and Datagrid

supports two templates in addition to the above five.SelectedItem Template controls how a

selected item is formatted and EditItemTemplate controls how an item selected for editing is

formatted.

99. What is ViewState ? and how it is managed ?ASP.NET ViewState is a new kind of state service that developers can use to track UI state on

a per-user basis. Internally it uses an an old Web programming trick-roundtripping state in a

hidden form field and bakes it right into the page-processing framework.It needs less code to

write and maintain state in your Web-based forms.

100. What is web.config file ? Web.config file is the configuration file for the Asp.net web

application. There is one web.config file for one asp.net application which configures the

particular application. Web.config file is written in XML with specific tags having specific

meanings.It includes databa which includes connections,Session States,Error

Handling,Security etc. For example :

< configuration >< appSettings >

< add key="ConnectionString"value="server=localhost;uid=sa;pwd=;database=MyDB" / >


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< /appSettings >< /configuration >

101. What is advantage of viewstate and what are benefits?

When a form is submitted in classic ASP, all form values are cleared. Suppose you have

submitted a form with a lot of information and the server comes back with an error. You will

have to go back to the form and correct the information. You click the back button, and what

happens.......ALL form values are CLEARED, and you will have to start all over again! The site

did not maintain your ViewState.With ASP .NET, the form reappears in the browser window

together with all form values.This is because ASP .NET maintains your ViewState. The

ViewState indicates the status of the page when submitted to the server.

102. What tags do you need to add within the asp:datagrid tags to bind columns manually? SetAutoGenerateColumns Property to false on the datagrid tag and then use Column tag and an

ASP:databound tag

< asp:DataGrid runat="server" id="ManualColumnBinding" AutoGenerateColumns="False" >

< Columns >

< asp:BoundColumn HeaderText="Column1" DataField="Column1"/ >

< asp:BoundColumn HeaderText="Column2" DataField="Column2"/ >

< /Columns >

< /asp:DataGrid >

103. Which property on a Combo Box do you set with a column name, prior to setting the

DataSource, to display data in the combo box? DataTextField and DataValueField

104. Which control would you use if you needed to make sure the values in two different

controls matched? CompareValidator is used to ensure that two fields are identical.

105. What is validationsummary server control?where it is used?.

The ValidationSummary control allows you to summarize the error messages from all


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validation controls on a Web page in a single location. The summary can be displayed as a list,

a bulleted list, or a single paragraph, based on the value of the DisplayMode property. The

error message displayed in the ValidationSummary control for each validation control on the

page is specified by the ErrorMessage property of each validation control. If the ErrorMessage

property of the validation control is not set, no error message is displayed in theValidationSummary control for that validation control. You can also specify a custom title in

the heading section of the ValidationSummary control by setting the HeaderText property.

You can control whether the ValidationSummary control is displayed or hidden by setting the

ShowSummary property. The summary can also be displayed in a message box by setting the

ShowMessageBox property to true.

106. What is the sequence of operation takes place when a page is loaded?

BeginTranaction - only if the request is transacted

Init - every time a page is processed

LoadViewState - Only on postback

ProcessPostData1 - Only on postback

Load - every time

ProcessData2 - Only on Postback

RaiseChangedEvent - Only on Postback

RaisePostBackEvent - Only on Postback

PreRender - everytime

BuildTraceTree - only if tracing is enabled

SaveViewState - every time

Render - Everytime

End Transaction - only if the request is transacted

Trace.EndRequest - only when tracing is enabled

UnloadRecursive - Every request

107. Difference between asp and asp.net?.

"ASP (Active Server Pages) and ASP.NET are both server side technologies for building websites and web applications, ASP.NET is Managed compiled code - asp is interpreted. and

ASP.net is fully Object oriented. ASP.NET has been entirely re-architected to provide a highly

productive programming experience based on the .NET Framework, and a robust

infrastructure for building reliable and scalable web

applications."


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108. Name the validation control available in asp.net?.

RequiredField, RangeValidator,RegularExpression,Custom validator,compare Validator

109. What are the various ways of securing a web site that could prevent from hacking etc .. ?

1) Authentication/Authorization2) Encryption/Decryption

3) Maintaining web servers outside the corporate firewall. etc.,

110. What is the difference between in-proc and out-of-proc?

An inproc is one which runs in the same process area as that of the client giving tha advantage

of speed but the disadvantage of stability becoz if it crashes it takes the client application also

with it.Outproc is one which works outside the clients memory thus giving stability to the

client, but we have to compromise a bit on speed.

111. When youre running a component within ASP.NET, what process is it running within on

Windows XP? Windows 2000? Windows 2003? On Windows 2003 (IIS 6.0) running in native

mode, the component is running within the w3wp.exe process associated with the application

pool which has been configured for the web application containing the component.

On Windows 2003 in IIS 5.0 emulation mode, 2000, or XP, it's running within the IIS helper

process whose name I do not remember, it being quite a while since I last used IIS 5.0.

112. What does aspnet_regiis -i do ? Aspnet_regiis.exe is The ASP.NET IIS Registration tool

allows an administrator or installation program to easily update the script maps for an

ASP.NET application to point to the ASP.NET ISAPI version associated with the tool. The tool

can also be used to display the status of all installed versions of ASP. NET, register the

ASP.NET version coupled with the tool, create client-script directories, and perform other

configuration operations.

When multiple versions of the .NET Framework are executing side-by-side on a single

computer, the ASP.NET ISAPI version mapped to an ASP.NET application determines which

version of the common language runtime is used for the application.

The tool can be launched with a set of optional parameters. Option "i" Installs the version of

ASP.NET associated with Aspnet_regiis.exe and updates the script maps at the IIS metabase

root and below. Note that only applications that are currently mapped to an earlier version of

ASP.NET are affected


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113. What is a PostBack?

The process in which a Web page sends data back to the same page on the server.

114. What is ViewState? How is it encoded? Is it encrypted? Who uses ViewState? ViewState is

the mechanism ASP.NET uses to keep track of server control state values that don't otherwisepost back as part of the HTTP form. ViewState Maintains the UI State of a Page

ViewState is base64-encoded. It is not encrypted but it can be encrypted by setting

EnableViewStatMAC="true" & setting the machineKey validation type to 3DES. If you want to

NOT maintain the ViewState, include the directive < %@ Page EnableViewState="false" % > at

the top of an .aspx page or add the attribute EnableViewState="false" to any control.

115. What is the < machinekey > element and what two ASP.NET technologies is it used for?

Configures keys to use for encryption and decryption of forms authentication cookie data and

view state data, and for verification of out-of-process session state identification.There fore 2

ASP.Net technique in which it is used are Encryption/Decryption & Verification

116. What three Session State providers are available in ASP.NET 1.1? What are the pros and

cons of each? ASP.NET provides three distinct ways to store session data for your application:

in-process session state, out-of-process session state as a Windows service, and out-of-process

session state in a SQL Server database. Each has it advantages.

1.In-process session-state mode

Limitations:

* When using the in-process session-state mode, session-state data is lost if aspnet_wp.exe or

the application domain restarts.

* If you enable Web garden mode in the < processModel > element of the application's

Web.config file, do not use in-process session-state mode. Otherwise, random data loss can

occur.

Advantage:

* in-process session state is by far the fastest solution. If you are storing only small amounts of

volatile data in session state, it is recommended that you use the in-process provider.

2. The State Server simply stores session state in memory when in out-of-proc mode. In this

mode the worker process talks directly to the State Server


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3. SQL mode, session states are stored in a SQL Server database and the worker process talks

directly to SQL. The ASP.NET worker processes are then able to take advantage of this simple

storage service by serializing and saving (using .NET serialization services) all objects within a

client's Session collection at the end of each Web request

Both these out-of-process solutions are useful primarily if you scale your application acrossmultiple processors or multiple computers, or where data cannot be lost if a server or process

is restarted.

117. What is the difference between HTTP-Post and HTTP-Get?

As their names imply, both HTTP GET and HTTP POST use HTTP as their underlying

protocol. Both of these methods encode request parameters as name/value pairs in the HTTP

request.

The GET method creates a query string and appends it to the script's URL on the server that

handles the request.

The POST method creates a name/value pairs that are passed in the body of the HTTP request

message.

118. Name and describe some HTTP Status Codes and what they express to the requesting

client. When users try to access content on a server that is running Internet Information

Services (IIS) through HTTP or File Transfer Protocol (FTP), IIS returns a numeric code that

indicates the status of the request. This status code is recorded in the IIS log, and it may also be

displayed in the Web browser or FTP client. The status code can indicate whether a particularrequest is successful or unsuccessful and can also reveal the exact reason why a request is

unsuccessful. There are 5 groups ranging from 1xx - 5xx of http status codes exists.

101 - Switching protocols.

200 - OK. The client request has succeeded

302 - Object moved.

400 - Bad request.

50013 - Web server is too busy.

119. Explain < @OutputCache% > and the usage of VaryByParam, VaryByHeader.

OutputCache is used to control the caching policies of an ASP.NET page or user control. To


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cache a page @OutputCache directive should be defined as follows < %@ OutputCache

Duration="100" VaryByParam="none" %>

VaryByParam: A semicolon-separated list of strings used to vary the output cache. By default,

these strings correspond to a query string value sent with GET method attributes, or aparameter sent using the POST method. When this attribute is set to multiple parameters, the

output cache contains a different version of the requested document for each specified

parameter. Possible values include none, *, and any valid query string or POST parameter

name.

VaryByHeader: A semicolon-separated list of HTTP headers used to vary the output cache.

When this attribute is set to multiple headers, the output cache contains a different version of

the requested document for each specified header.

120. What is the difference between repeater over datalist and datagrid?The Repeater class is

not derived from the WebControl class, like the DataGrid and DataList. Therefore, the

Repeater lacks the stylistic properties common to both the DataGrid and DataList. What this

boils down to is that if you want to format the data displayed in the Repeater, you must do so

in the HTML markup. The Repeater control provides the maximum amount of flexibility over

the HTML produced. Whereas the DataGrid wraps the DataSource contents in an HTML , and the DataList wraps the contents in either an HTML < table > or < span > tags

(depending on the DataList's RepeatLayout property), the Repeater adds absolutely no HTMLcontent other than what you explicitly specify in the templates. While using Repeater control,

If we wanted to display the employee names in a bold font we'd have to alter the

"ItemTemplate" to include an HTML bold tag, Whereas with the DataGrid or DataList, we

could have made the text appear in a bold font by setting the control's ItemStyle-Font-Bold

property to True. The Repeater's lack of stylistic properties can drastically add to the

development time metric. For example, imagine that you decide to use the Repeater to display

data that needs to be bold, centered, and displayed in a particular font-face with a particular

background color. While all this can be specified using a few HTML tags, these tags will

quickly clutter the Repeater's templates. Such clutter makes it much harder to change the look

at a later date. Along with its increased development time, the Repeater also lacks any built-in

functionality to assist in supporting paging, editing, or editing of data. Due to this lack of

feature-support, the Repeater scores poorly on the usability scale.


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However, The Repeater's performance is slightly better than that of the DataList's, and is more

noticeably better than that of the DataGrid's. Following figure shows the number of requests

per second the Repeater could handle versus the DataGrid and DataList

121. Can we handle the error and redirect to some pages using web.config?

Yes, we can do this, but to handle errors, we must know the error codes; only then we can take

the user to a proper error message page, else it may confuse the user.

CustomErrors Configuration section in web.config file:

The default configuration is:

< customErrors mode="RemoteOnly" defaultRedirect="Customerror.aspx" >

< error statusCode="404" redirect="Notfound.aspx" / >

< /customErrors >

If mode is set to Off, custom error messages will be disabled. Users will receive detailed

exception error messages.

If mode is set to On, custom error messages will be enabled.

If mode is set to RemoteOnly, then users will receive custom errors, but users accessing the site

locally will receive detailed error messages.

Add an < error > tag for each error you want to handle. The error tag will redirect the user to

the Notfound.aspx page when the site returns the 404 (Page not found) error.

[Example]

There is a page MainForm.aspx

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)

Handles MyBase.Load

'Put user code to initialize the page here

Dim str As System.Text.StringBuilder

str.Append("hi") ' Error Line as str is not instantiated

Response.Write(str.ToString)

End Sub

[Web.Config]


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< customErrors mode="On" defaultRedirect="Error.aspx"/ >

' a simple redirect will take the user to Error.aspx [user defined] error file.

< customErrors mode="RemoteOnly" defaultRedirect="Customerror.aspx" >

< error statusCode="404" redirect="Notfound.aspx" / >< /customErrors >

'This will take the user to NotFound.aspx defined in IIS.

122. How do you implement Paging in .Net?

The DataGrid provides the means to display a group of records from the data source (for

example, the first 10), and then navigate to the "page" containing the next 10 records, and so on

through the data.

Using Ado.Net we can explicit control over the number of records returned from the data

source, as well as how much data is to be cached locally in the DataSet.

1.Using DataAdapter.fill method give the value of 'Maxrecords' parameter (Note: - Don't use it

because query will return all records but fill the dataset based on value of 'maxrecords'

parameter).

2.For SQL server database, combines a WHERE clause and a ORDER BY clause with TOP

predicate.

3.If Data does not change often just cache records locally in DataSet and just take some records

from the DataSet to display.

123. What is the difference between Server.Transfer and Response.Redirect? Server.Transfer() :

client is shown as it is on the requesting page only, but the all the content is of the requested

page. Data can be persist across the pages using Context.Item collection, which is one of the

best way to transfer data from one page to another keeping the page state alive.

Response.Dedirect() :client knows the physical location (page name and query string as well).

Context.Items loses the persistence when navigate to destination page. In earlier versions of

IIS, if we wanted to send a user to a new Web page, the only option we had was


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Response.Redirect. While this method does accomplish our goal, it has several important

drawbacks. The biggest problem is that this method causes each page to be treated as a

separate transaction. Besides making it difficult to maintain your transactional integrity,


of code. Second, you lose access to all of the properties in the Request object. Sure, there areworkarounds, but they're difficult. Finally, Response.Redirect necessitates a round trip to the

client, which, on high-volume sites, causes scalability problems. As you might suspect,

Server.Transfer fixes all of these problems. It does this by performing the transfer on the server

without requiring a roundtrip to the client.

Response.Redirect sends a response to the client browser instructing it to request the second

page. This requires a round-trip to the client, and the client initiates the Request for the second

page. Server.Transfer transfers the process to the second page without making a round-trip to

the client. It also transfers the HttpContext to the second page, enabling the second page accessto all the values in the HttpContext of the first page.

124. Can you create an app domain?

Yes, We can create user app domain by calling on of the following overload static methods of

the System.AppDomain class

1. Public static AppDomain CreateDomain(String friendlyName)

2. Public static AppDomain CreateDomain(String friendlyName, Evidence securityInfo)

3. Public static AppDomain CreateDomain(String friendlyName, Evidence securityInfo,AppDomainSetup info)

4. Public static AppDomain CreateDomain(String friendlyName, Evidence securityInfo, String

appBasePath, String appRelativeSearchPath, bool shadowCopyFiles)

125. What are the various security methods which IIS Provides apart from .NET ?

The various security methods which IIS provides are

a) Authentication Modes

b) IP Address and Domain Name Restriction

c) DNS Lookups DNS Lookups

d) The Network ID and Subnet Mask

e) SSL


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126. What is Web Gardening? How would using it affect a design?

The Web Garden Model: The Web garden model is configurable through the section of the

machine.config file. Notice that the section is the only configuration section that cannot beplaced in an application-specific web.config file. This means that the Web garden mode applies

to all applications running on the machine. However, by using the node in the machine.config

source, you can adapt machine-wide settings on a per-application basis.

Two attributes in the section affect the Web garden model. They are webGarden and cpuMask.

The webGarden attribute takes a Boolean value that indicates whether or not multiple worker

processes (one per each affinitized CPU) have to be used. The attribute is set to false by default.

The cpuMask attribute stores a DWORD value whose binary representation provides a bit

mask for the CPUs that are eligible to run the ASP.NET worker process. The default value is -1

(0xFFFFFF), which means that all available CPUs can be used. The contents of the cpuMask

attribute is ignored when the webGarden attribute is false. The cpuMask attribute also sets an

upper bound to the number of copies of aspnet_wp.exe that are running.

Web gardening enables multiple worker processes to run at the same time. However, you

should note that all processes will have their own copy of application state, in-process session

state, ASP.NET cache, static data, and all that is needed to run applications. When the Web

garden mode is enabled, the ASP.NET ISAPI launches as many worker processes as there areCPUs, each a full clone of the next (and each affinitized with the corresponding CPU). To

balance the workload, incoming requests are partitioned among running processes in a round-

robin manner. Worker processes get recycled as in the single processor case. Note that

ASP.NET inherits any CPU usage restriction from the operating system and doesn't include

any custom semantics for doing this.

All in all, the Web garden model is not necessarily a big win for all applications. The more

stateful applications are, the more they risk to pay in terms of real performance. Working data

is stored in blocks of shared memory so that any changes entered by a process are immediately

visible to others. However, for the time it takes to service a request, working data is copied in

the context of the process. Each worker process, therefore, will handle its own copy of working

data, and the more stateful the application, the higher the cost in performance. In this context,

careful and savvy application benchmarking is an absolute must.


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Changes made to the section of the configuration file are effective only after IIS is restarted. In

IIS 6, Web gardening parameters are stored in the IIS metabase; the webGarden and cpuMask

attributes are ignored.

127. What is view state?.where it stored?.can we disable it?The web is state-less protocol, so the page gets instantiated, executed, rendered and then

disposed on every round trip to the server. The developers code to add "statefulness" to the

page by using Server-side storage for the state or posting the page to itself. When require to

persist and read the data in control on webform, developer had to read the values and store

them in hidden variable (in the form), which were then used to restore the values. With advent

of .NET framework, ASP.NET came up with ViewState mechanism, which tracks the data

values of server controls on ASP.NET webform. In effect,ViewState can be viewed as "hidden

variable managed by ASP.NET framework!". When ASP.NET page is executed, data values

from all server controls on page are collected and encoded as single string, which then

assigned to page's hidden atrribute "< input type=hidden >", that is part of page sent to the

client.

ViewState value is temporarily saved in the client's browser.ViewState can be disabled for a

single control, for an entire page orfor an entire web application. The syntax is:

Disable ViewState for control (Datagrid in this example)

< asp:datagrid EnableViewState="false" ... / >

Disable ViewState for a page, using Page directive

< %@ Page EnableViewState="False" ... % >

Disable ViewState for application through entry in web.config

< Pages EnableViewState="false" ... / >

Date post:	30-May-2018
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