VB.NET Important Question Answers.

1. What is VB.NET?

Visual Basic .NET (VB.NET) is an object-oriented computer programming language implemented on the .NET Framework. Although it is an evolution of classic Visual Basic language, it is not backwards-compatible with VB6, and any code written in the old version does not compile under VB.NET.

2. What is entry point method of VB.NET program?

Sub Main indicates the entry point of VB.Net program.

3. What are Shared methods?

Shared methods or static methods can be invoked without creating an object of the class.

4. What are Shared variables?

Shared declares a shared variable, which is not associated with any specific instance of a class or structure, rather available to all the instances of the class or structure.

5. What are Shadows variable?

Shadows indicate that the variable re-declares and hides an identically named element, or set of overloaded elements, in a base class.

6. What are Static variable?

Static indicates that the variable will retain its value, even when the after termination of the procedure in which it is declared.

7. How to create a constant in VB.NET?

In VB.Net, constants are declared using the Const statement. The Const statement is used at module, class, structure, procedure, or block level for use in place of literal values.

8. What is the purpose of Ansi keyword in VB.NET?

Ansi − Specifies that Visual Basic should marshal all strings to American National Standards Institute (ANSI) values regardless of the name of the external procedure being declared.

9. What is the purpose of Assembly keyword in VB.NET?

Assembly − Specifies that an attribute at the beginning of a source file applies to the entire assembly.

10. What is the purpose of Async keyword in VB.NET?

Async − Indicates that the method or lambda expression that it modifies is asynchronous. Such methods are referred to as async methods. The caller of an async method can resume its work without waiting for the async method to finish.

11. What is the purpose of Auto keyword in VB.NET?

Auto − The charsetmodifier part in the Declare statement supplies the character set information for marshaling strings during a call to the external procedure. It also affects how Visual Basic searches the external file for the external procedure name. The Auto modifier specifies that Visual Basic should marshal strings according to .NET Framework rules.

12. What is the purpose of ByRef keyword in VB.NET?

ByRef − Specifies that an argument is passed by reference, i.e., the called procedure can change the value of a variable underlying the argument in the calling code. It is used under the contexts of −

·        Declare Statement

·        Function Statement

·        Sub Statement

13. What is the purpose of ByVal keyword in VB.NET?

ByVal − Specifies that an argument is passed in such a way that the called procedure or property cannot change the value of a variable underlying the argument in the calling code. It is used under the contexts of −

·        Declare Statement

·        Function Statement

·        Operator Statement

·        Property Statement

·        Sub Statement

14. What is the purpose of Default keyword in VB.NET?

Default − Identifies a property as the default property of its class, structure, or interface.

15. What is the purpose of Friend keyword in VB.NET?

Friend − Specifies that one or more declared programming elements are accessible from within the assembly that contains their declaration, not only by the component that declares them.

16. Friend access is often the preferred level for an application's programming elements, and Friend is the default access level of an interface, a module, a class, or a structure.

17. What is the purpose of In keyword in VB.NET?

In − It is used in generic interfaces and delegates.

18. What is the purpose of Iterator keyword in VB.NET?

Iterator − Specifies that a function or Get accessor is an iterator. An iterator performs a custom iteration over a collection.

19. What is the purpose of Key keyword in VB.NET?

Key − The Key keyword enables you to specify behavior for properties of anonymous types.

20. What is the purpose of Module keyword in VB.NET?

Module − Specifies that an attribute at the beginning of a source file applies to the current assembly module. It is not same as the Module statement.

21. What is the purpose of MustInherit keyword in VB.NET?

MustInherit − Specifies that a class can be used only as a base class and that you cannot create an object directly from it.

22. What is the purpose of MustOverride keyword in VB.NET?

MustOverride − Specifies that a property or procedure is not implemented in this class and must be overridden in a derived class before it can be used.

23. What is the purpose of Narrowing keyword in VB.NET?

Narrowing − Indicates that a conversion operator (CType) converts a class or structure to a type that might not be able to hold some of the possible values of the original class or structure.

24. What is the purpose of NotInheritable keyword in VB.NET?

NotInheritable − Specifies that a class cannot be used as a base class.

25. What is the purpose of NotOverridable keyword in VB.NET?

NotOverridable − Specifies that a property or procedure cannot be overridden in a derived class.