ASP.Net

Define Error Events in Asp.Net?

In ASP.Net when any unhandled exception accurs in application then an event occures,that event called Error event.Two types of Event:
1. Page_Error:When exception occures in a page then this event raised.
2. Application_error:Application_Error event raised when unhandled exceptions in the ASP.NET application and is implemented in global.asax.
The error event have two method:
1. GetLastError: Returns the last exception that occurred on the server.
2. ClearError: This method clear error and thus stop the error to trigger subsequent error event.

Why the exception handling is important for an application?

Exception handling prevents the unusual error in the asp.net application,when apllication executed.If the exceptions are handled properly, the application will never get terminated abruptly.

Explain the aim of using EnableViewState property?

When the page is posted back to the server, the server control is recreated with the state stored in viewstate.It allows the page to save the users input on a form across postbacks. It saves all the server side values for a given control into ViewState, which is stored as a hidden value on the page before sending the page to the clients browser. 

What are the two levels of variable supported by Asp.net?

1. Page level variable:String ,int ,float.
2. Object level variable:Session level, Application level.

Difference between Session object and Profile object in ASP.NET?

Profile object:
1. Profile object is persistent.
2. Its uses the provider model to store information.
3. Strongly typed
4. Anonymous users used mostly.

Session object:
1. Session object is non-persistant.
2. Session object uses the In Proc, Out Of Process or SQL Server Mode to store information.
3. Not strongly typed.
4. Only allowed for authenticated users.

What is the Default Expiration Period For Session and Cookies,and maximum size of viewstate?

The default Expiration Period for Session is 20 minutes.
The default Expiration Period for Cookie is 30 minutes.
The maximum size of the viewstate is 25% of the page size

What is the use of Global.asax File in ASP.NET Application ?

The Global.asax file, can be stored in root directory and accesible for web-sites,is an optional file.This Global.asax file contained in HttpApplicationClass.we can declare global variables like variables used in master pages because these variables can be used for different pages right.Importent feature is that its provides more security in comparision to other.
It handle two event:
1.Application-level  
2.Session-level events.

Global.asax File itself configured but it can not be accessed.while one request is in processing it is impossible to send another request, we can not get response for other request and even we can not start a new session.
while adding this Global.asax file to our application by default it contains five methods,
Those methods are:
1.Application_Start.
2.Application_End.
3.Session_Start.
4.Session_End.
5.Application_Error.

What is the Purpose of System.Collections.Generic ?

For more safty and better performance strongly typed collections are useful for the user. System.Collections.Generic having interfaces and classes which define strongly typed generic collections.

What is GAC and name of the utility used to add an assembly into the GAC ?

GAC(Global Assembly Cache) for an effective sharing of assemblies.GAC refers to the machine-wide code cache in any of the computers that have been installed with common language runtime.Global Assembly Cache in .NET Framework acts as the central place for private registering assemblies.
\"gacutil.exe\" utility used to add assembly in GAC

Whether we can use vbscript and javascript combination for validation?

WE cant use them togather,since compiler are different.

What are the different states in ASP.NET?

There are three types of state:
1. View state: Under the client-side state managment.The ViewState property provides a dictionary object for retaining values between multiple requests for the same page. When an ASP.NET page is processed, the current state of the page and controls is hashed into a string and saved in the page as a hidden field. 
2. Application state:Under the server side state managment. ASP.NET allows you to save values using application state, a global storage mechanism that is accessible from all pages in the Web application. Application state is stored in the Application key/value dictionary.
3. Session state:Under server side state managment . ASP.NET allows you to save values using session state, a storage mechanism that is accessible from all pages requested by a single Web browser session.

Define State managment?

This is passible to at a time many request occures.State management is the process by which maintained state and page information over multiple requests for the same or different pages.
Two types of State Managment:
1. Client side state managment:This stores information on the client\'s computer by embedding the information into a Web page,uniform resource locator(url), or a cookie.
2. Server side state managment: There are two state Application State,Session State. 

What is Authentication and Authorization ?

An authentication system is how you identify yourself to the computer. The goal behind an authentication system is to verify that the user is actually who they say they are.
Once the system knows who the user is through authentication, authorization is how the system decides what the user can do.

Discribe Client Side State Management?

Client side state managment have:
a. Stores information on the client\'s computer by embedding the information into a Web page.
b. A uniform resource locator(url).
c. Cookie.
To store the state information at the client end terms are:
1. View State:It is used by the Asp.net page framework to automatically save the values of the page and of each control just prior to rendering to the page.Asp.Net uses View State to track the values in the Controls. You can add custom values to the view state.
2. Control State:When user create a custom control that requires view state to work properly, you should use control state to ensure other developers dont break your control by disabling view state.
3. Hidden fields:Like view state, hidden fields store data in an HTML form without displaying it in the user\'s browser. The data is available only when the form is processed.
4. Cookies: Cookies store a value in the user\'s browser that the browser sends with every page request to the same server. Cookies are the best way to store state data that must be available for multiple Web pages on a web site.
5. Query Strings: Query strings store values in the URL that are visible to the user. Use query strings when you want a user to be able to e-mail or instant message state data with a URL.

Describe Server Side State Management ?

Sever side state managment provied Better security,Reduced bandwidth.
1. Application State: This State information is available to all pages, regardless of which user requests a page.
2. Session State Session State information is available to all pages opened by a user during a single visit.

What is SessionID?

To identify the request from the browser used sessionID. SessionId value stored in a cookie. Configure the application to store SessionId in the URL for a \"cookieless\" session.  

What is the Session Identifier?

Session Identifier is :
1. To identify session. 
2. It has SessionID property.
3. When a page is requested, browser sends a cookie with a session identifier. 
4. Session identifier is used by the web server to determine if it belongs to an existing session or not. If not, then Session ID is generated by the web server and sent along with the response.  

Advantages of using Session State?

Advantages:
1. It is easy to implement.
2. Ensures platform scalability,works in the multi-process configuration.
3. Ensures data durability, since session state retains data even if ASP.NET work process restarts as data in Session State is stored in other process space. 

Disadvantages of using Session State ?

Disadvatages:
1. It is not advisable to use session state when working with large sum of data.Because Data in session state is stored in server memory.
2. Too many variables in the memory effect performance. Because session state variable stays in memory until you destroy it.   

What are the Session State Modes? Define each Session State mode supported by ASP.NET.

ASP.NET supports three Session State modes.
1. InProc:This mode stores the session data in the ASP.NET worker process and fastest among all of the storage modes.Its Also effects performance if the amount of data to be stored is large.
2. State Server:This mode maintained on a different system and session state is serialized and stored in memory in a separate process.
State Server mode is serialization and de-serialization of objects. State Server mode is slower than InProc mode as this stores data in an external process.
3. SQL Server:This mode can be used in the web farms and reliable and secures storage of a session state.In this storage mode, the Session data is serialized and stored in a database table in the SQL Server database.
  
  

What is a Master Page in Asp.Net?

For consistent layout for the pages in application used Master Pages.A single master page defines the look and feel and standard behavior that you want for all of the pages (or a group of pages) in your application.Then user create individual content pages that share all the information and lay out of a Master Page.

What are the 2 important parts of a master page and file extension for a Master Page?

The following are the 2 important parts of a master page
1. The Master Page itself
2. One or more Content Pages
The file extention for Master Page is \".master\".

How do you identify a Master Page and how do you bind a Content Page to a Master Page?

The master page is identified by a special @ Master directive that replaces the @ Page directive that is used for ordinary .aspx pages.
MasterPageFile attribute of a content page\'s @ Page directive is used to bind a Content Page to a Master Page.

Can you dynaimically assign a Master Page?

   void Page_PreInit(Object sender, EventArgs e) {
    
        if (Request.Browser.IsBrowser(\"IE\")) {
           this.MasterPageFile = \"ArticleMaster_IE.master\";
        }
        else if (Request.Browser.IsBrowser(\"Mozilla\")) {
           this.MasterPageFile = \"ArticleMaster_FireFox.master\";
        }
        else {
           this.MasterPageFile = \"ArticleMaster.master\";
        }
    }

From the content page code how can you reference a control on the master page?

Use the FindControl() method as shown in the code sample below.
void Page_Load()
{
// Gets a reference to a TextBox control inside
// a ContentPlaceHolder
ContentPlaceHolder ContPlaceHldr = (ContentPlaceHolder)Master.FindControl (\"ContentPlaceHolder1\");
if(ContPlaceHldr != null)
{
TextBox TxtBox = (TextBox)ContPlaceHldr.FindControl(\"TextBox1\");
if(TxtBox != null)
{
TxtBox.Text = \"WHERE R4R\";
}
}
// Gets a reference to a Label control that not in
// a ContentPlaceHolder
Label Lbl = (Label)Master.FindControl(\"Label1\");
if(Lbl != null)
{
Lbl.Text = \"R4R HERE\";
}
}

What is Globalization?

Globalization is the process of creating an application that meets the needs of users from multiple cultures.
This process involves translating the user interface elements of an application into multiple languages, using the correct currency, date and time format, calendar, writing direction, sorting rules, and other issues. 

What are the 3 different ways to globalize web applications?

Detect and redirect approach : In this approach we create a separate Web application for each supported culture, and then detect the users culture and redirect the request to the appropriate application. This approach is best for applications with lots of text content that requires translation and few executable components.
Run-time adjustment approach : In this approach we create a single Web application that detects the users culture and adjusts output at run time using format specifiers and other tools. This approach is best for simple applications that present limited amounts of content.
Satellite assemblies approach : In this approach we create a single Web application that stores culture-dependent strings in resource files that are compiled into satellite assemblies. At run time, detect the users culture and load strings from the appropriate assembly. This approach is best for applications that generate content at run time or that have large executable components.

What are the steps to follow to get user\'s culture at run time?

1. Get the Request objects UserLanguages property.
2. Use the returned value with the CultureInfo class to create an object representing the users current culture.

For example, the following code gets the users culture and displays the English name and the abbreviated name of the culture in a label the first time the page is displayed:

private void Page_Load(object sender, System.EventArgs e)
{
// Run the first time the page is displayed
if (!IsPostBack)
{
// Get the user\'s preferred language.
string sLang = Request.UserLanguages[0];
// Create a CultureInfo object from it.
CultureInfo CurrentCulture = new CultureInfo(sLang);
lblCulture.Text = CurrentCulture.EnglishName + \": \" +
CurrentCulture.Name;
}
}

What do you mean by neutral cultures?

Neutral cultures represent general languages, such as English or Spanish and a specific language and region.ASP.NET assigns that culture to all the threads running for that Web application.When user set culture attribute for a Web application in Web.config.ASP.NET maintains multiple threads for a Web application within the aspnet_wp.exe worker process. 

What is the advantage of using Windows authentication in a Web application?

The advantage of Windows authentication:
1. Web application can use the exact same security that applies to your corporate network like user names, passwords, and permissions.
2. To access the Web application users logged on to the network. It is importent that user does\'nt logged on again.

What is the default authentication method when you create a new Web application project?

Windows authentication is the default authentication method when you create a new Web application project.

How do you get a User Identity?

Using the User objects Identity property. The Identity property returns an object that includes the user name and role information, as shown in the following code:

private void Page_Load(object sender, System.EventArgs e)
{
Label1.Text = User.Identity.IsAuthenticated.ToString();
Label2.Text = User.Identity.Name;
Label3.Text = User.Identity.AuthenticationType;
}

How do you determine, what is the role of the current user?

The User object provides an IsInRole method to determine the role of the current user, as shown in the following example:
if(User.IsInRole(\"Administrators\"))
{
///////
}

Can you specify authorization settings both in Web.config and in IIS?

Yes,It wil be done. For this, the IIS setting is evaluated first and then the setting in Web.config is evaluated. Hence we can say,the most restrictive setting will be used.

What are the 2 Layouts supported by a Web form in ASP.NET?

1. Grid layout:  Pages using grid layout will not always display correctly in non-Microsoft browsers,and controls are placed exactly where they draw.It means they have absolute positions on the page. Use grid layout for Microsoft Windows style applications, in which controls are not mixed with large amounts of text.
2. Flow layout: Controls relative to other elements on the page.
Controls that appear after the new element move down if you add elements at run time.
Flow layout for document-style applications, in which text and controls are intermingled.

What is the difference between Literal and Lable Control?

We use literals control if we want to typed text using HTML formating and without using property.We typed HTML code in .cs file when used literals.
Lable control when displayed already formated.Typed text can not be formated in .cs file.

What is smart navigation?

Smart navigation is, cursor position is maintained when the page gets refreshed due to the server side validation and the page gets refreshed.

Explain the difference between a database administrator and a data administrator.

What is the difference between Server.Transfer and Response.Redirect?

1. Server.Transfer() performs server side redirection of the page avoiding extra round trip. While The Response. Redirect() method can be used to redirect the browser to specified url.
2. Server.Transfer is used to post a form to another page. Response.Redirect is used to redirect the user to another page or site.

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

1. A DataSet can represent an entire relational database in memory, complete with tables, relations, and views. 
2. A DataSet is designed to work without any continuing connection to the original data source. 
3. Data in a DataSet is bulk-loaded, rather than being loaded on demand. 

Can you give an example of when you might use it?

When you want to inherit (use the functionality of) another class. Base Class Employee. A Manager class could be derived from the Employee base class. 

Can the action attribute of a server-side

No, You have to use Server.Transfer to pass the data to another page.

What is the role of global.asax.

Store global information about the application

Whats a bubbled event?

When you have a complex control, like DataGrid, writing an event processing routine for each object (cell, button, row, etc.) is quite tedious. The controls can bubble up their eventhandlers, allowing the main DataGrid event handler to take care of its constituents.

Describe the difference between inline and code behind.

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. 

Which method do you invoke on the DataAdapter control to load your generated dataset with data?

The .Fill() method 

Can you edit data in the Repeater control?

No, it just reads the information from its data source 

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

ItemTemplate 

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

Use the AlternatingItemTemplate 

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?

You must set the DataSource property and call the DataBind method. 

Name two properties common in every validation control?

ControlToValidate property and Text property

Where does the Web page belong in the .NET Framework class hierarchy?

System.Web.UI.Page 

Where do you store the information about the user�s locale?

System.Web.UI.Page.Culture

Can you give an example of what might be best suited to place in the Application Start and Session Start subroutines?

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

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

 SOAP is the preferred protocol. 

To test a Web service you must create a windows application or Web application to consume this service?

The webservice comes with a test page and it provides HTTP-GET method to test.

Whats the difference between struct and class in C#?

1. Structs cannot be inherited. 
2. Structs are passed by value, not by reference. 
3. Struct is stored on the stack, not the heap.

Where do the reference-type variables go in the RAM?

The references go on the stack, while the objects themselves go on the heap. However, in reality things are more elaborate. 

What is the difference between the value-type variables and reference-type variables in terms of garbage collection?

The value-type variables are not garbage-collected, they just fall off the stack when they fall out of scope, the reference-type objects are picked up by GC when their references go null. 

What is main difference between Global.asax and Web.Config?

aASP.NET uses the global.asax to establish any global objects that your Web application uses. The .asax extension denotes an application file rather than .aspx for a page file. Each ASP.NET application can contain at most one global.asax file. The file is compiled on the first page hit to your Web application. ASP.NET is also configured so that any attempts to browse to the global.asax page directly are rejected. However, you can specify application-wide settings in the web.config file. The web.config is an XML-formatted text file that resides in the Web sites root directory. Through Web.config you can specify settings like custom 404 error pages, authentication and authorization settings for the Web site, compilation options for the ASP.NET Web pages, if tracing should be enabled, etc

What is SOAP and how does it relate to XML?

The Simple Object Access Protocol (SOAP) uses XML to define a protocol for the exchange of information in distributed computing environments. SOAP consists of three components: an envelope, a set of encoding rules, and a convention for representing remote procedure calls. Unless experience with SOAP is a direct requirement for the open position, knowing the specifics of the protocol, or how it can be used in conjunction with HTTP, is not as important as identifying it as a natural application of XML. 

Using XSLT, how would you extract a specific attribute from an element in an XML document?

Successful candidates should recognize this as one of the most basic applications of XSLT. If they are not able to construct a reply similar to the example below, they should at least be able to identify the components necessary for this operation: xsl:template to match the appropriate XML element, xsl:value-of to select the attribute value, and the optional xsl:apply-templates to continue processing the document.

Whats a Windows process?

Its an application thats running and had been allocated memory. 

What is typical about a Windows process in regards to memory allocation?

Each process is allocated its own block of available RAM space, no process can access another process code or data. If the process crashes, it dies alone without taking the entire OS or a bunch of other applications down. 

Explain what relationship is between a Process, Application Domain, and Application?

A process is an instance of a running application. An application is an executable on the hard drive or network. There can be numerous processes launched of the same application (5 copies of Word running), but 1 process can run just 1 application.

Define the possible implementations of distributed applications in .NET?

.NET Remoting and ASP.NET Web Services. If we talk about the Framework Class Library, noteworthy classes are in System.Runtime.Remoting and System.Web.Services. 

Give your idea when deciding to use .NET Remoting or ASP.NET Web Services?

1. Remoting is a more efficient communication exchange when you can control both ends of the application involved in the communication process.  2. Web Services provide an open-protocol-based exchange of informaion.  Web Services are best when you need to communicate with an external organization or another (non-.NET) technology.

Do you know the proxy of the server object in .NET Remoting?

This process is known as marshaling. It handles the communication between real server object and the client object. We can say that It is a fake copy of the server object that resides on the client side and behaves as if it was the server. 
 

What are remotable objects in .NET Remoting?

1. They can be marshaled across the application domains.
2. You can marshal by value, where a deep copy of the object is created and then passed to the receiver. You can also marshal by reference, where  just a reference to an existing object is passed. 

In .NET Remoting, What are channels?

Channels represent the objects that transfer the other serialized objects from one application domain to another and from one computer to another, as well as one process to another on the same box. A channel must exist before an object can be transferred. 

What security measures exist for .NET Remoting?

None. 

What is Singleton activation mode?

A single object is instantiated regardless of the number of clients accessing it. Lifetime of this object is determined by lifetime lease. 

How to configure a .NET Remoting object via XML file?

It can be done via machine.config and application level .config file (or web.config in ASP.NET). Application-level XML settings take precedence over machine.config. 

How can you automatically generate interface for the remotable object in .NET?

Use the Soapsuds tool.

What is the top .NET class that everything is derived from?

System.Object. 

Difference between System.String and System.Text.StringBuilder classes?

System.String is immutable.  System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed. 

Difference between the System.Array.Clone() and System.Array.CopyTo()?

The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array.  The CopyTo() method copies the elements into another existing array.  Both perform a shallow copy.  A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array.  A deep copy (which neither of these methods performs) would create a new instance of each element\'s object, resulting in a different, yet identacle object.

What is the .NET collection class that allows an element to be accessed using a unique key?

HashTable. 

What class is underneath the SortedList class?

A sorted HashTable. 

How to prevent your class from being inherited by another class?

We use the sealed keyword to prevent the class from being inherited. 

How to allowed a class to be inherited, but it must be prevent the method from being over-ridden?

Just leave the class public and make the method sealed. 

Define abstract class?

1. A class that cannot be instantiated.
2. An abstract class is a class that must be inherited and have the methods overridden.
3. An abstract class is essentially a blueprint for a class without any implementation

When you declared a class as abstract?

1. When at least one of the methods in the class is abstract.  
2. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.  

Define interface class ?

Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes. 

How to Specify the accessibility modifier for methods inside the interface?

They all must be public, and are therefore public by default. 

What is the difference between an interface and abstract class ?

1. In an interface class, all methods are abstract and there is no implementation.  In an abstract class some methods can be concrete.
2. In an interface class, no accessibility modifiers are allowed.  An abstract class may have accessibility modifiers. 

Tell me implicit name of the parameter that gets passed into the set property of a class?

The data type of the value parameter is defined by whatever data type the property is declared as. 

What does the keyword virtual declare for a method?

The method or property can be overridden.