23 March 2013

VB.Net -- General Questions and Answers Part-I

VB.Net -- General Questions and Answers:


1.            What is VB.NET?
                VB.Net is windows based programming language. It supports oops concept.

2.            What is the base class of .net?
                System. Object.

3.            What is Intermediate Language?
                Microsoft Intermediate Language (MSIL or IL) is the CPU -independent instruction set into which .Net framework programs are compiled. It contains instructions for loading, storing initializing, and calling methods on objects.

4.            What is Common Language Runtime?
                CLR also known as Common Language Run time provides an environment in which program are executed, it activate object, perform security check on them, lay them out in the memory, execute them and garbage collect them.

5. What is an Assembly?
                Assembly is the basic building blocks of the .net framework. They are the logical grouping of the functionality in a physical file.

6.  What are the advantages of an assembly?
                Increased performance. Better code management and encapsulation. It also introduces the n-tier concepts and business logic.

7.  What is Code Access Security?
                CAS - Code Access Security is the part of the .NET security model that determines whether or not a piece of code is allowed to run, and what resources it can use when it is running.

8.  What is the use of internal keyword?
                Internal keyword is one of the access specifier available in .Net framework, that makes a type visible in a given assembly, for e.g : a single dll can contain multiple modules.

9. What are class access modifiers?
    Access modifiers are keywords used to specify the declared accessibility of a member or a type. This section introduces the four access modifiers:
    Public,    Protected,    Internal,    Protected inertnal,    Private.

10. What is portable executable?
                The file format used for executable programs and for files to be linked together to form executable programs.

11. What is tracing?
                Tracing refers to collecting information about the application while it is running. You use tracing information to troubleshoot an application.

12. What is serialization?
                Serialization is the process of converting an object into a stream of bytes.
De-serialization is the opposite process of creating an object from a stream of bytes.
Serialization/De-serialization is mostly used to transport objects.

13. How a base class method is hidden?
                Hiding a base class method by declaring a method in derived class with keyword new. This will override the base class method and old method will be suppressed.

14.          What is the use of JIT?
                JIT (Just - In - Time) is a compiler which converts MSIL code to Native Code (ie. CPU-specific code that runs on the same computer architecture).

15.          Which method do you invoke on the Data Adapter control to load your generated dataset with data?
                  Fill () method is used to fill load the data in dataset.

16.          What is the purpose of an Assembly?
                An assembly controls many aspects of an application. The assembly handles versioning, type and class scope, security permissions, as well as other metadata including references to other assemblies and resources. The rules described in an assembly are enforced at runtime.

17.          What is Authentication and Authorization?
                Authentication is the process of identifying users. Authentication is identifying/validating the user against the credentials (username and password).
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.

18. What are the types of Authentication?
                 There are 3 types of Authentication.
·         Windows authentication
·         Forms authentication
·         Passport authentication.

19.          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.

20. What is reflection?
                All .NET compilers produce metadata about the types defined in the modules they produce. This metadata is packaged along with the module (modules in turn are packaged together in assemblies), and can be accessed by a mechanism called reflection.

21.          What is an Application Domain? How they get created?
                An Application Domain can be thought of as a lightweight processes controlled by the .Net runtime. Application Domains are usually created by hosts like Windows Shell, ASP.NET and IE. When you run a .NET application from the command-line, the host is the Shell. The Shell creates a new Application Domain for every application.

22. How do you convert a string into an integer in .NET?
23.          What is the use of Error Provider Control?
                The Error Provider control is used to indicate invalid data on a data entry form.

24.          What does assert() method 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.
25.   What are Option Strict and Option Explicit?
.Net generally allows implicit conversion of any data types. In order to avoid data loss during data type conversion, Option Strict keyword is used and it ensures compile time notification of these types of conversions.
Option Explicit is the keyword used in a file to explicitly declare all variables using declare keywords like Dim, Private, Public or Protected. If undeclared variable name persists, an error occurs at compile time.
26.   What is ReDim keyword and its use?
Redim keyword is exclusively used for arrays and it is used to change the size of one or more dimensions of an array that has been already declared. Redim can free up or add elements to an array whenever required.
                Dim intArray(7, 7) AsInteger
                ReDim Preserve intArray(7, 8)
                ReDim intArray(7, 7)
27.   What is HashTable?
HashTable is set to be items with key and value pairs. Keys are referred as indexes and quick search can be performed for values by searching through the keys.

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