Commonly Asked Asp.net Interview Questions & Answers

Asp.net Interview Questions & Answers

 

Asp.net Interview Questions

  1. What is the difference between Custom Control and User Control?
    Custom Controls are compiled code (Dlls), easier to use, difficult to create, and can be
    placed in toolbox. Drag and Drop controls. Attributes can be set visually at design time. Can
    be used by Multiple Applications (If Shared Dlls), Even if Private can copy to bin directory of
    web application add reference and use. Normally designed to provide common functionality
    independent of consuming Application. User Controls are similar to those of ASP include
    files, easy to create, can not be placed in the toolbox and dragged – dropped from it. A User
    Control is shared among the single application files.

  2. What is the difference between ASP Session State and ASP.Net Session State?
    ASP session state relies on cookies, Serialize all requests from a client, does not survive
    process shutdown, Can not maintained across machines in a Web farm.

  3. Difference between ASP Session and ASP.NET Session?
    Asp.net session supports cookie less session & it can span across multiple servers.

  4. Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?
    (Repeated but more explanatory)
    In ADO, the in-memory representation of data is the recordset. In ADO.NET, it is the
    dataset. There are important differences between them.
    o A recordset looks like a single table. If a recordset is to contain data from multiple
    database tables, it must use a JOIN query, which assembles the data from the various
    database tables into a single result table. In contrast, a dataset is a collection of one or
    more tables. The tables within a dataset are called data tables; specifically, they are
    DataTable objects. If a dataset contains data from multiple database tables, it will
    typically contain multiple DataTable objects. That is, each DataTable object typically
    corresponds to a single database table or view. In this way, a dataset can mimic the
    structure of the underlying database. A dataset usually also contains relationships. A
    relationship within a dataset is analogous to a foreign-key relationship in a database —
    that is, it associates rows of the tables with each other. For example, if a dataset
    contains a table about investors and another table about each investor’s stock
    purchases, it could also contain a relationship connecting each row of the investor table
    with the corresponding rows of the purchase table. Because the dataset can hold
    multiple, separate tables and maintain information about relationships between them,
    it can hold much richer data structures than a recordset, including self-relating tables
    and tables with many-to-many relationships.
    o In ADO you scan sequentially through the rows of the recordset using the ADO
    MoveNext method. In ADO.NET, rows are represented as collections, so you can loop
    through a table as you would through any collection, or access particular rows via
    ordinal or primary key index. DataRelation objects maintain information about master
    and detail records and provide a method that allows you to get records related to the
    one you are working with. For example, starting from the row of the Investor table for
    “Nate Sun,” you can navigate to the set of rows of the Purchase table describing his
    purchases. A cursor is a database element that controls record navigation, the ability to
    update data, and the visibility of changes made to the database by other users.
    ADO.NET does not have an inherent cursor object, but instead includes data classes that
    provide the functionality of a traditional cursor. For example, the functionality of a
    forward-only, read-only cursor is available in the ADO.NET DataReader object.
    o Minimized Open Connections: In ADO.NET you open connections only long enough to
    perform a database operation, such as a Select or Update. You can read rows into a
    dataset and then work with them without staying connected to the data source. In ADO
    the recordset can provide disconnected access, but ADO is designed primarily for
    connected access. There is one significant difference between disconnected processing
    in ADO and ADO.NET. In ADO you communicate with the database by making calls to an
    OLE DB provider. In ADO.NET you communicate with the database through a data
    adapter (an OleDbDataAdapter, SqlDataAdapter, OdbcDataAdapter, or
    OracleDataAdapter object), which makes calls to an OLE DB provider or the APIs
    provided by the underlying data source. The important difference is that in ADO.NET the
    data adapter allows you to control how the changes to the dataset are transmitted to
    the database — by optimizing for performance, performing data validation checks, or
    adding any other extra processing. Data adapters, data connections, data commands,
    and data readers are the components that make up a .NET Framework data provider.
    Microsoft and third-party providers can make available other .NET Framework data
    providers that can be integrated into Visual Studio.
    o Sharing Data between Applications. Transmitting an ADO.NET dataset between
    applications is much easier than transmitting an ADO disconnected recordset. To
    transmit an ADO disconnected recordset from one component to another, you use COM
    marshalling. To transmit data in ADO.NET, you use a dataset, which can transmit an XML
    stream.
    o Richer data types.COM marshalling provides a limited set of data types — those defined
    by the COM standard. Because the transmission of datasets in ADO.NET is based on an
    XML format, there is no restriction on data types. Thus, the components sharing the
    dataset can use whatever rich set of data types they would ordinarily use.
    o Performance. Transmitting a large ADO recordset or a large ADO.NET dataset can
    consume network resources; as the amount of data grows, the stress placed on the
    network also rises. Both ADO and ADO.NET let you minimize which data is transmitted.
    But ADO.NET offers another performance advantage, in that ADO.NET does not require
    data-type conversions. ADO, which requires COM marshalling to transmit records sets
    among components, does require that ADO data types be converted to COM data types.
    o Penetrating Firewalls.A firewall can interfere with two components trying to transmit
    disconnected ADO recordsets. Remember, firewalls are typically configured to allow
    HTML text to pass, but to prevent system-level requests (such as COM marshalling) from
    passing.

  5. Which class does the web page belong to in ASP.Net?
    System.Web.UI.Page

  6. Which class deals with the user’s locale information?
    System.Web.UI.Page.Culture

  7. What data type does the RangeValidator control support?
    Integer, Date and String.

  8. What is the difference between Server.Transfer and Response.Redirect?
    Server.Transfer, transfers the control of a web page, posting a form data, while
    Response.Redirect simply redirects a page to another page, it can not post a form data to
    another page. Server.Transfer is more efficient over the Response.Redirect, because
    Response.Redirect causes a round trip to server as the page is processed once again on the
    client and a request is made to server there after.

  9. Can you give an example of what might be best suited to place in the Application_Start and
    Session_Start subroutines?
    All the global declarations or the variables used commonly across the application can be
    deployed under Application_Start. All the user specific tasks or declarations can be dealt in
    the Session_Start subroutine.

  10. Difference between Classic ASP and ASP.Net?
     ASP is Interpreted language based on scripting languages like Jscript or VBScript.
     ASP has Mixed HTML and coding logic.
     Limited development and debugging tools available.
     Limited OOPS support.
     Limited session and application state management.
     Poor Error handling system.
     No in-built support for XML.
     No fully distributed data source support.
    while
     ASP.Net is supported by compiler and has compiled language support.
     Separate code and design logic possible.
     Variety of compilers and tools available including the Visual studio.Net.
     Completely Object Oriented.
     Complete session and application state management.
     Full proof error handling possible.
     Full XML Support for easy data exchange.
     Fully distributed data source support.

  11. What’s the difference between Response.Write () and Response.Output.Write ()?
    Response.Outout.Write allows us to write the formatted out put.

  12. What is the difference between static or dynamic assemblies?
    Assemblies can be static or dynamic. Static assemblies can include .NET Framework types
    (interfaces and classes), as well as resources for the assembly (bitmaps, JPEG files, resource
    files, and so on). Static assemblies are stored on disk in portable executable (PE) files. You
    can also use the .NET Framework to create dynamic assemblies, which are run directly from
    memory and are not saved to disk before execution. You can save dynamic assemblies to
    disk after they have executed.

  13. Differences between dataset.clone and dataset.copy
    dataset.clone copies just the structure of dataset (including all the datatables, schemas,
    relations and constraints.); however it doesn’t copy the data. On the other hand
    dataset.copy, copies both the dataset structure and the data.

  14. Describe the difference between inline and code behind.
    Inline code written along with the html and design blocks in an .aspx page. Code-behind is
    code written in a separate file (.cs or .vb) and referenced by the .aspx page.

  15. What is ViewState?
    ViewState is a .Net mechanism to store the posted data among post backs. ViewState allows the
    state of objects to be stored in a hidden field on the page, saved on client side and transported
    back to server whenever required.

  16. What is the lifespan for items stored in ViewState?
    Items stored in a ViewState exist for the life of the current page, including the post backs on the
    same page.

  17. Can we disable ViewState, If, yes how?
    ViewState can be disabled by using “EnableViewState” property set to false.

  18. What’s a bubbled event?
    When a complex control like datalist or datagrid, which contains a child control, using an
    itemcommand can listen to the events raised by the child control in the main control. The process
    of listening to the child control in the main or parent control is called as event bubbling.

  19. Which method do you invoke on the DataAdapter control to load your generated dataset with
    data?
    DataAdapter’s fill () method is used to fill load the data in dataset.

  20. Can you edit data in the Repeater control?
    No, it just reads the information from its data source.

  21. Which template is to be provided in the Repeater control in order to display a data? Which
    template will display every other row in another color?
    ItemTemplate, AlternatingItemTemplate

  22. What are the most important property and most important method of a Repeater control?
    The DataSource property and DataBind () method.

  23. What is Authentication and Authorization?
    Authentication is the process of identifying users. Authentication is identifying/validating the user
    against the credentials (username and password) and Authorization performs after authentication.
    Authorization is the process of granting access to those users based on identity. Authorization
    allowing access of specific resource to user.

  24. What are the types of Authentication? Describe.
    There are 3 types of Authentication. Windows, Forms and Passport Authentication.
     Windows authentication uses the security features integrated into the Windows NT
    and Windows XP operating systems to authenticate and authorize Web application
    users.
     Forms authentication allows you to create your own list/database of users and
    validate the identity of those users when they visit your Web site.
     Passport authentication uses the Microsoft centralized authentication provider to
    identify users. Passport provides a way to for users to use a single identity across
    multiple Web applications. To use Passport authentication in your Web application,
    you must install the Passport SDK.

  25. What are the types of comment in C#?
    There are 3 types of comments in C#.
    Single line (//), Multi line (/* */) and Page/XML Comments (///).

  26. What is an ArrayList?
    The ArrayList object is a collection of items containing a single data type values.

  27. What is a HashTable?
    The Hashtable object contains items in key/value pairs. The keys are used as indexes, and very
    quick searches can be made for values by searching through their keys.

  28. What is SortedList?
    The SortedList object contains items in key/value pairs. A SortedList object automatically sorts
    items in alphabetic or numeric order.

  29. What is a Literal Control?
    The Literal control is used to display text on a page. The text is programmable. This control does
    not let you apply styles to its content!

  30. What is Side-by-Side Execution?
    The CLR allows any versions of the same-shared DLL (shared assembly) to execute at the same
    time, on the same system, and even in the same process. This concept is known as side-by-side
    execution.

  31. What are the different types of Caching?
    There are three types of Caching:
     Output Caching: stores the responses from an asp.net page.
     Fragment Caching: Only caches/stores the portion of page (User Control)
     Data Caching: is Programmatic way to Cache objects for performance.

  32. What are the different types of Validation Controls?
    There are six types of validation controls available:
     RequiredFieldValidator
     RangeValidator
     RegularExpressionValidator
     CompareValidator
     CustomValidator
     ValidationSummary

  33. How to Manage State in ASP.Net?
    There are several ways to manage a state.
     ViewState
     QueryString
     Cookies
     Session
     Application

  34. What base class all Web Forms inherit from?
    System.Web.UI.Page.

  35. What method do you use to explicitly kill a user’s Session?
    HttpContext.Current.Session.Abandon().

  36. What are the layouts of ASP.NET Pages?
    GridLayout and FlowLayout. GridLayout positions the form object on absolute x and y co-ordinates
    of the screen. FlowLayout positions the form objects relative to each other.

  37. What is the Web User Control?
    Combines existing Server and/or HTML controls by using VS.Net to create functional units that
    encapsulate some aspects of UI. Resides in Content Files, which must be included in project in
    which the controls are used.

  38. What is the Composite Custom Control?
    combination of existing HTML and Server Controls.

  39. If I’m developing an application that must accommodate multiple security levels though secure
    login and my ASP.NET web application is spanned across three web-servers (using round-robin load
    balancing) what would be the best approach to maintain login-in state for the users?
    You can use the security state maintained using a database. (Use Authentication mode as
    database)

  40. What’s the difference between Codebehind=”MyCode.aspx.cs” and Src=”MyCode.aspx.cs”?
    Visual Studio uses the Codebehind attribute to distinguish the page source or programming logic
    from the design. Also the src attribute will make the page compile on every request. That is the
    page will not be compiled in advance and stored in the bin as a dll instead it will be compiled at run
    time.

  41. Suppose you want a certain ASP.NET function executed on MouseOver over a certain button or
    textbox. Where do you add an event handler?
    Every web control has an ability to add the attributes on client side which will execute on client
    side and run a client side script like a javascript function.
    btnSubmit.Attributes.Add(“onMouseOver”,”someClientCode();”) //For on mouse over of a button
    TextBox1.Attributes.Add(“onFocus”,“ClearText();”) //For on focus of a text box

  42. Explain what a diffgram is and a good use for one?
    The DiffGram is one of the two XML formats that you can use to render DataSet object contents to
    XML. For reading database data to an XML file to be sent to a Web Service.

  43. Name two properties common in every validation control?
    ControlToValidate and Text property.

  44. What tags do you need to add within the Datagrid tags to bind columns manually?
    Set AutoGenerateColumns Property to false on the Datagrid tag.

  45. What tag do you use to add a hyperlink column to the DataGrid?
    <asp:HyperLinkColumn></asp:HyperLinkColumn>

  46. What is the transport protocol you use to call a Web service?
    SOAP (Simple Object Access Protocol) is the preferred protocol.

  47. Where on the Internet would you look for Web services?
    http://www.uddi.org

  48. Which control would you use if you needed to make sure the values in two different controls
    matched?
    CompareValidator Control

  49. What are the assembly entry points? An Assembly can have how many entry points at a time?
    An assembly can have only one entry point from DllMain, WinMain or Main.

  1. What does an assembly contain?
    • Manifest – The metadata describing the information below.
    • Assembly name – Aids in versioning and visibility scope.
    • Version information – The version number is integrated into the assembly’s identity.
    • Types – Boundaries and scopes of methods, classes, properties, events and attributes.
    • Locale – Information describing language/culture.
    • Cryptographic Hash – Public key encoded hash acting as version/security check.
    • Security Permissions – The permissions within the assembly determine the permissions that can
    be granted for all aspects of the assembly contents.

  2. What does an assembly manifest contains?
    It contains assembly name, version number (major.minor.build.revision) and culture Information.
    It also specifies the strong name information, which is useful for shared assemblies, and list of files,
    an assembly contains. It also provides information for type references in an assembly and other
    referenced assemblies.

  3. Which tool is used to deploy an assembly, so as the assembly is available to all the application?
    The GacUtil.exe is the tool, which allows us to add any assembly to the windows GAC (Global
    Assembly Catche).

  4. How many catch statements can be associated with single try statement?
    There can be a zero or more catch statement for each try statement. So it has not limit to the
    number of catch statement per try statement.

  5. What is Console and System a Class/a Data Member/a routine/a namespace or a type?
    Console is a class and System is namespace.

  6. How many values can be returned from a method in C#?
    Only one value can be returned from method, however you can use ref or out parameters to
    change more than one value in called method.

  7. How to declare a variable named “this” in C#, with data type string?
    string @this;

  8. Can we change the dimension of Array at run time like Array [3, 4]?
    Yes, We can change only the first position of array dimension.

  9. What keyword is used to accept a variable number of parameter in a method?
    “params” keyword is used as to accept variable number of parameters.

  10. What is a Namespace? What is the use of a namespace?
    Namespaces are logical grouping of classes and other types in hierarchical structure. Namespaces
    are useful to avoid collision or ambiguity among the classes and type names. Another use of the
    namespace is to arrange a group of classes for a specific purpose.

  11. What does a keyword using works for?
    Using is just a convention or a short-cut method which allows us to access the classes in a
    namespace by referencing it once. So when ever we want use the classes or methods in them, we
    can avoid typing the entire namespace hierarchy. However it is not a good practice when there are
    likely chances to have name ambiguity or collision of class names.

  12. What is Enums in C#?
    Enums or Enumerators are used to declare a set of related constants (default start with 0); they
    are only available with primitive data types like int and short etc.

  13. What is Delegates?
    Delegates are a type-safe, object-oriented implementation of function pointers and are used in
    many situations where a component needs to call back to the component that is using it. Delegates
    are generally used as basis of events, which allow any delegate to easily be registered for as event.

  14. Which are the namespaces that are imported automatically by Visual Studio in ASP.Net?
    There are 7 namespaces which are imported automatically.
     System
     System.Collections
     System.IO
     System.web
     System.web.UI
     System.web.UI.HTMLControls
     System.web.UI.WebControls

  15. Which namespaces are used for data access?
     System.Data
     System.Data.OleDB
     System.Data.SQLClient

  16. What do you mean by boxing and un-boxing?
    C# provides us with Value types and Reference Types. Value Types are stored on the stack and
    Reference types are stored on the heap. The conversion of value type to reference type is known as
    boxing and converting reference type back to the value type is known as un-boxing.
    e.g.
    int x = 10;
    object o = x ; // Implicit boxing
    object o = (object) x; // Explicit Boxing
    x = o; // Implicit Un-Boxing
    x = (int)o; // Explicit Un-Boxing

  17. What are the different methods available under sqlcommand class to access the data?
     ExecuteReader – Used where one or more records are returned – SELECT Query.
     ExecuteNonQuery – Used where it affects a state of the table and no data is being
    queried – INSERT, UPDATE, DELETE, CREATE and SET queries.
     ExecuteScalar – Used where it returns a single record(a single value normally) – SQL
    Functions like MIN(), NAX()

  18. What are the different types of Session state management options available with ASP.NET?
    ASP.NET provides In-Process & Out-of-Process state management,
    Also known as “In-Proc” and “Out-Proc”. In-Proc stores the session in memory of the web server,
    that is on the same server the ASP.Net page is.
    On the other hand Out-Proc session state management stores the session data on external data
    source, which can be a SQL Server or Server State Service. Out-of-Process state management
    requires the objects stored in session, must be serializable.

  19. What is Remoting? Give Example.
    Remoting is a means by which one operating system process, or program, can communicate with
    another process. The two processes can exist on the same computer or on two computers
    connected by a LAN or the Internet. Web services are probably the best known type of remoting,
    but they are not the only option.

  20. When would you use .NET Remoting and when Web services?
    Use remoting for more efficient exchange of information when you control both ends of the
    application. Use Web services for open-protocol-based information exchange when you are just a
    client or a server with the other end belonging to someone else.

  21. What’s a proxy of the server object in .NET Remoting?
    It’s a fake copy of the server object that resides on the client side and behaves as if it was the
    server. It handles the communication between real server object and the client object. This process
    is also known as marshaling.

  22. What are remotable objects in .NET Remoting?
    Remotable objects are the objects that can be marshaled across the application domains. 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.

  23. What is Marshalling?
    Marshaling is a process of making an object in one process (the server) available to another
    process (the client). There are two ways to achieve the marshalling.
    i. Marshal by value: the server creates a copy of the object passes the copy to the client.
    When a client makes a call to an object marshaled by value (MBV), the server creates an
    exact copy and sends that copy to the client. The client can then use the object’s data
    and executable functionality directly within its own process or application domain
    without making additional calls to the server. Objects that the application accesses
    frequently are best remoted using MBV.
    ii. Marshal by reference: the client creates a proxy for the object and then uses the proxy
    to access the object. When a client makes a call to an object marshaled by reference
    (MBR), the .NET framework creates a proxy in the client’s application domain and the
    client uses that proxy to access the original object on the server. Large objects that the
    application accesses relatively infrequently are good candidates for MBR.

  24. What is a Static class? What are its features?
    Static class is a class which can be used or accessed without creating an instance of the class.
    Important Features:
    iii. Static class only contains static members and a private constructor.
    iv. Static class cannot be instantiated.
    v. Static classes are sealed by default and therefore cannot be inherited.

  25. What is sealed class? What are its features?
    Sealed classes are those classes which can not be inherited and thus any sealed class member can
    not be derived in any other class. A sealed class cannot also be an abstract class.
    In C# structs are implicitly sealed; therefore, they cannot be inherited.

  26. Can we declare a method as sealed?
    In C# a method can’t be declared as sealed. However when we override a method in a derived
    class, we can declare the overridden method as sealed. By declaring it as sealed, we can avoid
    further overriding of this method.
    E.g.
    using System;
    class MyClass1
    {
    public int x;
    public int y;
    public virtual void Method() {
    Console.WriteLine(“virtual method”); }
    }
    class MyClass : MyClass1
    {
    public override sealed void Method() {
    Console.WriteLine(“sealed method”); }
    }
    class MainClass
    { public static void Main() {
    MyClass1 mC = new MyClass();
    mC.x = 110;
    mC.y = 150;
    Console.WriteLine(“x = {0}, y = {1}”, mC.x, mC.y);
    mC.Method(); }
    }

  27. What is a DataSet ?
    A DataSet is an in memory representation of data loaded from any data source.

  28. What is a DataTable?
    A DataTable is a class in .NET Framework and in simple words a DataTable object represents a
    table from a database.

  29. If you want to view an Assembly how to you go about it? What is ILDASM?
    You can use the MSIL Disassembler (Ildasm.exe) to view Microsoft intermediate language (MSIL)
    information in a file. If the file being examined is an assembly, this information can include the
    assembly’s attributes, as well as references to other modules and assemblies. This information can
    be helpful in determining whether a file is an assembly or part of an assembly, and whether the file
    has references to other modules or assemblies.

  30. Where is version information stored of an assembly?
    The version number is stored in the assembly manifest along with other identity information,
    including the assembly name and public key, as well as information on relationships and identities
    of other assemblies connected with the application.

  31. Is versioning applicable to private assemblies?
    No

  32. How to create a shared assembly or add an assembly to GAC?
    There are several ways an assembly can be added to GAC.
    vi. Use .msi installer designed to work with the global assembly cache.
    vii. Use GACUtil.exe provided by the .NET Framework SDK.
    viii. Use Windows Explorer to drag assemblies into the cache.

  33. What is a Page Life Cycle of an ASP.Net page?
    There are various stages described as under.
     Init
     LoadViewState
     LoadPostBackData
     Load
     RaisePostBackDataChangedEvent
     RaisePostBackEvents
     Pre-Render
     SaveViewState
     Render
     Unload

  34. Can the action attribute of a server-side <form>tag be set to a value and if not how can you
    possibly pass data from a form to a subsequent Page?
    No, Assigning value will not work because will be overwritten at the time of rendering. We can
    assign value to it by register a startup script which will set the action value of form on client-side.
    On other hand we can use Server.Transfer or Response.Redirect.

  35. How do you turn off cookies in one page of your asp.net application?
    We may not use them at the max, However to allow the cookies or not, is client side functionality.

  36. Which method do you use to redirect to user to another page without performing a round trip to
    Client?
    Server.Transfer(“AnotherPage.aspx”).

  37. How many namespaces are in .NET version 1.1?

  38. Should Validation occur on Client/Server Side for Date Input?
    Both. Client-side reduces extra round-trip. Server-Side ensures prevention against hacking and
    failure against automated requests.

  39. What are the web form events?
    ix. The first event that occurs in the life of a Web Form is the Init event. This is raised so
    that we can have initialization code for the page. The controls on the page are not yet
    created at this point. This event is raised once for each user of the page.
    x. The Load event follows the Init event. Subsequently, it is raised each time the page is
    requested. When this event is raised, all child controls of the Web Form are loaded and
    accessible. You should be able to retrieve data and populate the controls so that they
    can render themselves on the page when sent back to the client.
    xi. The PreRender event happens just before the page is rendered and sent back to the
    client. We don’t often handle this event; however, it depends on the situation.
    xii. The last event in the life of a Web Form is the Unload event. This happens when the
    page is unloaded from memory. Final cleanup should be done here.

  40. Why main function is static?
    To ensure there is only one entry point to the application.

  41. How CCW (COM Callable Wrapper) and RCW (Runtime Callable Wrapper) work?
    CCW: The .NET Framework includes support for COM clients to use .NET components. When a COM
    client needs to create a .NET object, the CLR creates the managed object and a COM callable
    wrapper (CCW) that wraps the object. The COM client interacts with the managed object through
    the CCW. The runtime creates only one CCW for a managed object, regardless of how many COM
    clients are using it.
    RCW: The .NET Framework includes extensive support for COM interoperability. To allow .NET
    clients to interact with a COM component, .NET uses an RCW—a special .NET proxy class that sits
    between your .NET code and the COM component. The RCW handles all the details, including
    marshaling data types, using the traditional COM interfaces, and handling COM events.

  42. How to generate XML from a dataset and vice versa?
    We can use WriteXml() and ReadXml() methods of DataSet Object.

  1. What is Session State Management? Describe.
    you can apply state management to your applications in a number of ways. Session State
    Management determines how the sessions are stored by the ASP.NET application. The default
    option is InProc. Other options include Off, StateServer, and SQLServer. Running sessions inprocess (InProc) means that the sessions are stored in the same process as the ASP.NET worker
    process. Therefore, if IIS is shut down and then brought up again, all the sessions are destroyed and
    unavailable to end users. StateServer means that sessions are stored out-of-process by a Windows
    service called ASPState. SQLServer is by far the most secure way to deal with your sessions. It
    stores them directly in SQL Server itself. Although it is the most secure method, it is also the least
    performance-efficient method.

  2. What base class do all web forms inherit from?
    System.Web.UI.Page

  3. Which two properties are on every validation control?
    ControlToValidate and ErrorMessage.

  4. How do you create a permanent cookie?
    Set the expiry date as datetime.maxvalue.

  5. What does WSDL stand for?
    Web Services Description Language.

  6. How is a property designated as read-only?
    Use only the get accessor.

  7. Which control would you use if you needed to make sure the values in two different controls
    matched?
    CompareValidator.

  8. To test a Web Service you must create a windows application or web application to consume this
    service? It is True/False?
    Every web service by default generates a test page, we need not create or consume the Web
    service in order to test it.

  9. What is the maximum length of a varchar in SQL Server? 255

  10. Is string a value type or a reference type?
    String is the reference type.

  11. Can multiple catch blocks be executed?
    No, once an exception fall under a catch block the control will never be passed to next catch block
    instead it will be passed to the finally block (if any or/and) the code next to the finally block.

  12. How do you generate documentation from the C# file commented properly with a commandline compiler?
    Compile it with a /doc switch.

  13. What debugging tools come with the .NET SDK?
    CorDBG – command-line debugger, and DbgCLR – graphic debugger. Visual Studio .NET uses the
    DbgCLR. To use CorDbg, you must compile the original C# file using the /debug switch.

  14. What does assert () do?
    In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error
    dialog if the condition is false. The program proceeds without any interruption if the condition is
    true.

  15. What’s the difference between the Debug class and Trace class?
    Documentation looks the same. Use Debug class for debug builds, use Trace class for both debug
    and release builds.

  16. How do you debug an ASP.NET Web application?
    Attach the aspnet_wp.exe process to the DbgClr debugger.

  17. Name the 4 .NET authentification methods.
    ASP.NET, in conjunction with Microsoft Internet Information Services (IIS), can authenticate user
    credentials such as names and passwords using any of the following authentication methods:
    a. Windows: Basic, digest, or Integrated Windows Authentication (NTLM or Kerberos).
    b. Microsoft Passport authentication
    c. Forms authentication
    d. Client Certificate authentication

  18. Explain what a diffgram is and a good use for one?
    A DiffGram is an XML format that is used to identify current and original versions of data elements.
    The DataSet uses the DiffGram format to load and persists its contents, and to serialize its contents
    for transport across a network connection. When a DataSet is written as a DiffGram, it populates
    the DiffGram with all the necessary information to accurately recreate the contents, though not the
    schema, of the DataSet, including column values from both the Original and Current row versions,
    row error information, and row order.

  19. Where would you use an iHTTPModule, and what are the limitations of anyapproach 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.

  20. What method do you use to explicitly kill a user’s session?
    The Abandon method destroys all the objects stored in a Session object and releases their
    resources.
    If you do not call the Abandon method explicitly, the server destroys these objects when the
    session times out.
    Syntax: Session.Abandon

  21. How do you turn off cookies for one page in your site?
    Use the Cookie.Discard Property which 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.

  22. Which method do you use to redirect the user to another page without performing a round trip
    to the client?
    Server.transfer()

  23. Where do you store the information about the user’s locale?
    System.Web.UI.Page.Culture

  24. What’s the difference between Codebehind=”MyCode.aspx.cs” andSrc=”MyCode.aspx.cs”?
    CodeBehind is relevant to Visual Studio.NET only.

  25. What data type does the RangeValidator control support?
    Integer, String and Date.

  26. What is cookie less session? How it works?
    By default, ASP.NET will store the session state in the same process that processes the request,
    just as ASP does. If cookies are not available, a session can be tracked by adding a session identifier
    to the URL. This can be enabled by setting the following:
    <sessionState cookieless=”true” />

  27. What is State Management in .Net and how many ways are there to maintain a state in .Net?
    What is view state?
    Web pages are recreated each time the page is posted to the server. In traditional Web
    programming, this would ordinarily mean that all information associated with the page and the
    controls on the page would be lost with each round trip.
    To overcome this inherent limitation of traditional Web programming, the ASP.NET page
    framework includes various options to help you preserve changes — that is, for managing state.
    The page framework includes a facility called view state that automatically preserves property
    values of the page and all the controls on it between round trips.
    However, you will probably also have application-specific values that you want to preserve. To do
    so, you can use one of the state management options.
    Client-Based State Management Options:

– View State
– Hidden Form Fields
– Cookies
– Query Strings
Server-Based State Management Options
-Application State
-Session State
-Database Support

  1. What are the different modes for the sessionstates in the web.config file?
    Off Indicates that session state is not enabled.
    Inproc Indicates that session state is stored locally.
    StateServer Indicates that session state is stored on a remote server.
    SQLServer Indicates that session state is stored on the SQL Server.

  2. In a Webservice, need to display 10 rows from a table. So DataReader or DataSet is best choice?
    WebService will support only DataSet.

  3. What is singleton and what is singlecall?
    Singleton types never have more than one instance at any one time. If an instance exists, all client
    requests are serviced by that instance.
    Single Call types always have one instance per client request. The next method invocation will be
    serviced by a different server instance, even if the previous instance has not yet been recycled by
    the system.

  4. What is the difference between Compiler and Interpreter?
    Compiler:
    A compiler is a program that translates program (called source code) written in some high level
    language into object code. The compiler derives its name from the way it works, looking at the
    entire piece of source code and collecting and reorganizing the instructions. A compiler translates
    high-level instructions directly into machine language and this process is called compiling.
    Interpreter:
    An interpreter translates high-level instructions into an intermediate form, which it then executes.
    Interpreter analyzes and executes each line of source code in succession, without looking at the
    entire program; the advantage of interpreters is that they can execute a program immediately.
    Compilers require some time before an executable program emerges. However, programs
    produced by compilers run much faster than the same programs executed by an interpreter.
    Compiled programs generally run faster than interpreted programs. The advantage of an
    interpreter, however, is that it does not need to get through the compilation stage during which
    machine instructions are generated. This process can be time-consuming if the program is long. The
    interpreter, on the other hand, can immediately execute high-level programs. For this reason,
    interpreters are sometimes used during the development of a program, when a programmer wants
    to add small sections at a time and test them quickly.Because compilers translate source code into
    object code, which is unique for each type of computer, many compilers are available for the same
    language. For example, there is a C compiler for PCs and another for UNIX computers.

  5. Describe the role of inetinfo.exe, aspnet_isapi.dll andaspnet_wp.exe in the page loading
    process.
    inetinfo.exe is theMicrosoft IIS server running, handling ASP.NET requests among other things.When
    an ASP.NET request is received (usually a file with .aspx extension),the ISAPI filter aspnet_isapi.dll takes
    care of it by passing the request tothe actual worker process aspnet_wp.exe.

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