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Top 20 VB.Net Interview Questions and Answers
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Top 20 VB.Net Interview Questions and Answers

Published On: June 17, 2024

VB.Net Interview Questions and Answers

A wide range of applications, including desktop, web, and mobile applications, can be developed with VB.NET. The basic, middle, and advanced VB.NET interview questions and answers will all be covered in this article.

VB.Net Interview Questions and Answers for Freshers

1. What is Visual Basic?

Microsoft provides an Integrated Development Environment (IDE) and event-driven programming language called Visual Basic. It was designed to save programmers from having to delve too deeply into the Windows API to create both basic and advanced GUI-based programs for Windows. 

2. Explain VB.Net.

You can create multi-threaded programs using Vb.Net because it is platform-independent. It is a compiler language that is not backward compatible, in contrast to core VB. “Try…Catch” handles exceptions in it.

3. Describe Namespace.

Namespaces are only an organized way to represent classes, hierarchies, and interfaces in the .NET language. Namespaces are indices of a class library that are arranged hierarchically and are accessible to all.NET languages.

4. What is JIT?

Runtime execution environments can be created using Just In Time Compiler, or JIT. Three varieties of JIT are discernible:

Pre-JIT: It is assembled when an application is about to be deployed.

Econo-JIT: It invokes methods in real time.

Standard JIT: It calls an instantaneously compiled method during runtime and compiles it at that point.

5. Why is “event-driven” applied to Visual Basic?

The reason Visual Basic is referred to as “event-driven” is that user activities, including keystrokes, mouse clicks, and other interactions with the GUI components, control how the program flows. 

6. What is a VB form’s lifecycle?

A VB form runs through multiple phases, from load events (the form’s initialization) to unload events (the form’s termination). This allows developers to create code specific to each stage of the form’s existence, such as Activate, Deactivate, Resize, Paint, and more. 

7. In VB, how is error handling accomplished?

The On Error statement is the main tool used in Visual Basic for handling errors. Some variations are “On Error Resume Next,” which skips over errors and moves on to the next line of code, and “On Error GoTo [label],” which redirects the flow to a specific label when an error occurs. 

8. Explain ‘Option Explicit’?

When a module has ‘Option Explicit’ at the beginning, variables must be declared before they are used. This can improve the readability and maintainability of the code and stop possible run-time issues. 

9. Describe the ‘INTERNAL’ keyword in .Net.

The INTERNAL keyword is one of the access specifiers that will be displayed in a certain assembly, or DLL file. This is one binary component that is visible throughout the assembly.

10. What distinguishes Finalize() from Dispose() exactly?

Garbage collectors use the finalize() approach, which aids in the removal of unmanaged resources. Database connections are managed using the iDisposable interface, and window handles are among the other resources.

The IDisposable interface handles the dispose() method, which releases resources that are expressly unused. Dispose can be called when live references to the object are present.

VB.Net Interview Questions and Answers for Experienced Professionals

11. Name the different generations of garbage collectors.

Three distinct generations can be distinguished in the garbage collector.

Generation 0: It is regarded as a recently curated item in Generation 0 and has never been marked for collection.

Generation 1: The first generation is identified as a collection but is not avoided.

Generation 2: Those who have made it through multiple rounds of the Garbage Collector.

12. What is metadata?

Metadata is information about information about other data. It is a collection of data that offers details and descriptions of other data.

  • To make stored data more accessible and usable, it aids in organizing and documenting it.
  • It may contain information about the file’s name, size, type, creator, date, location, and method of linking to other files.

Without metadata, it would be far more difficult to understand and retrieve any given data set.

13. What keywords are in ReDim and how are they used?

To resize an array in Visual Basic, use the ReDim keyword. By redefining the array with a different number of elements, it enables the programmer to change the number of elements in the array. 

Only static or fixed-size arrays may utilize this ReDim keyword; dynamic arrays cannot. Unless the number and size of the items change, ReDim maintains the array’s contents during the resize operation.

To enlarge an array, use the ReDim keyword, as demonstrated in the example below:

Dim MyArray() As Integer

ReDim MyArray(10)

The MyArray array is declared with no size in the example above. The array is then resized to contain 10 elements using the ReDim keyword. 

Example Code Snippet

Dim DemoArray() As Integer ‘ Declaring a dynamic array. 

Redim DemoArray(10) ‘ Allocating 10 elements. 

For J = 1 To 10 ‘number loops 10 times.

DemoArray(J) = J ‘ Initializing the DemoArray. 

Next J

14. Explain VB.NET’s jagged arrays.

The code below shows an array of arrays called scores of integers.

Declaring a jagged array:

Dim marks As Integer()() = New Integer(10)(){}

The following sample of code demonstrates how to utilize a jagged array:

Module demoArray

  Sub Main()

     ‘ making one jagged array of 3 arrays of integers

     Dim arr As Integer()() = New Integer(2)() {}

     arr(0) = New Integer() {5, 6}

     arr(1) = New Integer() {15, 10}

     arr(2) = New Integer() {32, 60}

     Dim a, b As Integer

     ‘ printing the value of every array element      

     For a = 0 To 3

        For b = 0 To 1

           Console.WriteLine(“arr[{0},{1}] = {2}”, a, b, arr(a)(b))

        Next b

     Next a

     Console.ReadKey()

  End Sub

End Module

Output

arr[0][0]: 5

arr[0][1]: 6

arr[1][0]: 15

arr[1][1]: 10

arr[2][0]: 32

arr[2][1]: 60

15. In VB.NET, what do delegates mean?

One kind of object that can be used to refer to a method is a delegate. A delegate that is assigned to a method behaves exactly like that method. 

Objects called delegates act as stand-ins for methods. They are also known as type-safe function pointers since they resemble function pointers used in other programming languages. 

Delegates in Visual Basic are reference types that are built on the class “System.Delegate”, as opposed to function pointers.

16. Explain GLC in VB.Net.

Shared .NET assemblies are kept in the Global Assembly Cache (GLC). It’s used in the following criteria:

  • If .Net assemblies require any special security measures.
  • if data sharing between .Net applications and other programs is necessary.

17. Describe the application domain. How do application domains get created?

An application domain is a lightweight process that is managed by the .NET runtime. Hosts like Windows Shell, ASP.NET, and many more establish application domains.

The host is the shell, for instance, when you run a .net application from the command line. For each application, the shell generates a new application domain.

18. Explain Code Security in VB.Net.

The security features of the .NET framework protect code from unauthorized users. In .NET, there are two kinds of security:

  • Role-based security: Gives User Authorization
  • Code access security guards against unwanted calls to system resources.

19. Describe the significance of the keywords “Friend” and “WithEvents.”

WithEvents: In Visual Basic, variables that can react to events raised by an object are declared using the ‘WithEvents’ keyword. 

It enables event handling from an object that is dynamically formed at runtime by the developer without the need to manually connect event handlers at the time of object creation.

Friend keyword: Within the declaring assembly of VB.NET, the keyword “Friend” designates an access modifier that permits a member to be accessible only within that assembly and not to other assemblies. 

Between “Private” (available exclusively in the declaring type) and “Public” (accessible from any assembly), it is a compromise.

20. What in VB.Net is TRACE?

  • Using the built-in VB.Net function TRACE, text file is written to the output window both during design and execution. 
  • It is used to record and display the progress of an application during runtime.
  • Programmers may view how their programs perform at every step and ensure that everything functions as it should with their assistance, which is also helpful for troubleshooting.  
  • The immediate window, a text file, or the output window can all receive trace messages.

21. Explain Authorization and authentication

  • Authorization is the process of deciding which resources a user is permitted to access, whereas authentication is the process of confirming a user’s identity.
  • A two-step process starts with authentication. The second step in deciding what a user can do with a particular resource is authorization.

Three primary categories of authentication exist:

Single-factor authentication: The simplest kind, known as single-factor authentication, simply needs one piece of proof, such as a password, to be able to access data.

Two-factor authentication: Due to the requirement of two pieces of evidence—such as a password and a fingerprint—two-factor authentication is more secure than single-factor authentication.

Multi-factor authentication: The safest kind of authentication is multi-factor, which needs three or more pieces of proof to be accessed, including a password, a fingerprint, and an iris scan.

Conclusion

We hope you have gained expertise through our well-curated VB.Net interview questions and answers given here. Kickstart your development career by enrolling in our VB.Net training in Chennai.

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