VB.NET Interview Questions and Answers for 2025

In general, any data type may be implicitly transformed in .Net programming language, as it gives this option. 

Option Strict is implemented to prevent data leaking during data type conversions and to ensure compile-time notice of specific types of conversions. 

Option Explicit is a file keyword that is used to exclusively define each variable utilizing declare keywords which include Dim, Private, Public, and Protected. When an undefined variable name is identified, an error is thrown at compilation time. 

The constructor is used in conjunction with the keyword NEW. It can be used as a modifier or an operator. When used as a modifier, the NEW keyword conceals derived members from parent class members. When it's used as an operator, it generates objects for calling constructors. The NEW keyword generates a new object instance, imposes a constructor constraint on something like a type parameter, or declares another function to be a class constructor.  

A declaration or an assignment statement can both contain a NEW clause. When we execute the statement, it executes the appropriate constructor of said specified class, supplying whatever parameters we have supplied. 

Below is an example of how to use the NEW keyword: 

Dim teacher11 As New Teacher()

The ReDim statement is used to resize or expand a dynamic array that has already been declared officially with empty parentheses using a Private, Public, or Dim declaration (which are without dimension subscripts). Just use ReDim assertion repeatedly to change the array's number of elements as well as dimensions in an array. However, except if the array is part of a Variant, it is not possible to construct one data type array and then use ReDim to change to a different data type.  

If the array is kept in a Variant, the elements' types can be altered using an As type clause, except if the Preserve keyword is used, where in, in that case no data type modifications are permitted. 

Here's an example of how to use the ReDim keyword: 

Dim DemoArray() As Integer ' Declaring a dynamic array.  
Redim DemoArray(10) ' Allocating 10 elements.  
For J = 1 To 10 ' Looping for 10 times.  
DemoArray(J) = J ' Initializing the DemoArray.  
Next J 

In the above example, the ReDim command is used to allocate and reallocate data storage for dynamic array variables. It is assumed that the Option Base is 1. The ReDim keyword would be only applied to arrays and can be utilized to alter the size of one or more aspects of a previously defined array. Redim will free up space or help in adding elements to something like an array as needed.  

These are some VB.net OOPs interview questions that mostly come in the interviews.

Class access modifiers are keywords that can be used to indicate the declared visibility of a member or type. The following are the numerous forms of class access modifiers: 

• Public  
• Private 
• Protected 
• Internal 
• Protected Internal 

Globalization refers to the process of customizing our program to many cultures. We must acknowledge that our application's users may speak a language other than English and also that their language, in contrast to being a distinct language, observes some other conventions. Certain languages, for instance, should be presented from left to right, whilst others ought to be displayed from right to left. We must now examine not just the different languages, but also the different currencies, time and date settings, and colors associated with different civilizations. Globalization allows us to make programs available to anyone from any part of the world, irrespective of their language.

A.NET Framework assembly manifest is a text file that includes metadata about the script in a CLI assembly. It explains the relationships and dependencies of the components, in addition to the assembly's versioning, scope, and security permissions. The Manifest file format may be stored as a PE file. We may store the Version, Assembly Name, Culture, and key token as a Manifest.  

Nested classes are those that may be declared within the scope of another class. These classes are covered by the scope of the enclosed class and are accessible within that class's scope. 

An Enumerator or Enum is a value type that has a collection of constants supplied to the collection of the list. Enumeration is used when over one number must be defined.

CTS (Common Type System): The Common Type System defines the data types which managed programs can utilize (CTS). CTS specifies how these types are defined, used, and handled during runtime. It facilitates cross-language integration, safety, and high-performance code execution. The CTS rules may be used to construct lasses and values. Alternatively, we can understand something like this: CTS handles data types. As a result, we have a variety of languages, each with its own data type. While the data type of one language may be unintelligible to another, the.NET Framework language can grasp any data types. 

C# and VB.NET both provide integer data types. As a consequence, following compilation, a variable given as an int in C# and Integer in VB.NET uses the same structure Int32 from CTS as illustrated in the image below. CTS's structures and classes are shared with all languages and serve to promote language independence. As a result, it is referred to as CTS. 

CLS (Common Language Specification): CLS (Common Language Specification) is a subset of CTS. It defines a set of rules and limitations that every language which runs on the.NET framework must adhere to. CLS Compliant languages include those that adhere to this set of guidelines. CLS supports cross-language integration, often known as interoperability. For example, if we are discussing C# versus VB.NET, every sentence in C# must conclude with a semicolon. Although it is commonly referred to as statement Terminator, each statement in VB.NET must not end with a semicolon (;). 

While the syntax rules differ from language to language, CLR can comprehend them all because, in.NET, each language is turned into MSIL (Microsoft Intermediate Language) program after compiling, and MSIL code constitutes CLR's language specification. 

Managed code is a form of code written to take advantage of the features of a regulated runtime environment, like the CLR (Common Language Runtime) in the.NET Framework. Instead of being conducted directly by the windows OS, it is always carried out by the controlled runtime environment. The controlled runtime environment offers several functionalities to programs, including asgarbage collection, exception handling, type checking, bounds checking, and other functions that do not require human participation. It also provided a memory for the code, as well as type safety and other features. 

Built-in languages for applications, such as Java, VB.Net, and others, are always directed at realtime environment services to control execution, and programs written in all of these languages generally considered as managed code. 

In the.NET Framework scenario, the compiler always compiles the managed code in MSIL (Microsoft Intermediate Language) before building an executable. When the programmer executes the executable, the CLR's Just In Time (JIT) Compiler converts the intermediate language into native code specific to the architecture underlying. This method is executing in a controlled runtime execution environment, and the environment controls the functioning of the code. 

The managed code is run as shown below, also with source code written in any .NET Framework language. Because managed code is converted into an intermediate representation; the JIT compiler converts this intermediate language into platform-independent instructions. 

An assembly is a component of a .NET program that serves as the primary unit of all .NET applications. This assembly may be a DLL or an executable file. 

Strong Name is a significant feature of .Net that is used to uniquely identify shared assemblies. Strong name has resolved the issue of having several objects with the same name, and it may be assigned using Sn.exe.

There are two kinds of assemblies: 

• Private assemblies are often used by a unified platform and are kept in the application's directory. 
• A public assembly, also known as a shared assembly, is stored in the Global Assembly Cache (GAC), which may be used by several apps. 

Assembly is the physical grouping of any and all units, whereas Namespace is the logical grouping of classes. A namespace may include many assemblies. 

In general, .Net supports implicit conversion of all data types. Option Strict is applied to avoid data loss in data type conversion, and it assures compile time notice of certain sorts of conversions. 

Option Explicit is a file keyword that is used to explicitly declare any variables that employ declaration keywords such as Dim, Private, Public, or Protected. If an undeclared data type persists, then build error occurs. 

The redim keyword is only applicable to arrays and can be utilized to modify the size of one or even more elements of an already specified array. When needed, Redim can help open up space or add new elements to an array. 

Dim intArray(7, 7) As Integer 
ReDim Preserve intArray(7, 8) 
ReDim intArray(7, 7) 

The INTERNAL keyword comes among the access specifiers visible in a particular assembly, i.e., a DLL file. This is accessible throughout the assembly as a single binary component. 

The System.string class is not updateable, and it will produce new string objects rather than altering existing ones. Stringbuilder class allows for updating within the same string object. As a result, the string constructor procedure is both faster and more effective than the string class.

Hashtable elements are defined as key-value pairs. Keys are referred to as indexes, and a rapid search for values may be conducted by scanning through the keys. 

A class that may be defined within another class's scope. These classes are deemed to be inside the scope of the contained class and are therefore accessible inside that class or scope.

An Enumerator, often known as an Enum, is a value type that has a collection of constants assigned to the subset of the list. When more than a number has to be defined, enumeration is utilized. 

A delegate is an object that may be used to refer to a method. When we attach a delegate to a method, it functions precisely like that method. 

Example: 

public delegate int performaddition(int z, int b); 

VB.Net supports the following languages: 

• C# 
• VB.Net 
• COBOL 
• Perl 

Deep copy is nothing more than generating a new object and afterwards copying the existing object's non-static fields to the new object.

Garbage collector invokes the Finalize function, which allows us to free up unmanaged resources. Other resources, such as window handles and database connections, are managed through iDisposable interface. 

The Disposable interface handles the dispose method, which is used to explicitly release unneeded resources. Dispose can be invoked even if there are other references towards the object that are still alive.

Collection is indeed known as automated memory management, and it is used to recycle dynamically allocated memory automatically. Garbage collection is handled by a garbage collector, who will reclaim memory if it is demonstrated that it will be utilized.