.NET is a popular software development framework developed by Microsoft. It is used to build desktop, web, and mobile applications. It is an open-source platform that supports a wide range of programming languages, including C#, F#, and Visual Basic. The .NET framework provides a rich set of tools and libraries for developers to build robust and scalable applications. In this blog I have shared top 25 .Net Interview Questions with answers.

.NET Interview Questions and Answers

What is .NET?

.NET is a software development framework developed by Microsoft for building desktop, web, and mobile applications. It provides a common language runtime (CLR) that manages the execution of code and a class library that provides a set of reusable types and functionality.

What is the difference between ASP.NET WebForms and ASP.NET MVC?

ASP.NET WebForms is a page-based framework that uses a drag-and-drop model to create web applications. It provides a set of controls that abstract away much of the complexity of web development. In contrast, ASP.NET MVC is a pattern-based framework that separates an application into three components: Model, View, and Controller. It allows for greater control over the HTML and allows for easier testing and maintenance.

What is the CLR?

CLR (Common Language Runtime) is the heart of the .NET framework. It is responsible for executing code written in any .NET-supported language. It provides features such as memory management, type safety, security, and exception handling.

What is the CTS?

CTS (Common Type System) is a set of rules that defines how types are declared, used, and managed in the .NET framework. It ensures that types can be used across different languages and provides a consistent way to interact with objects.

What is the CLS?

CLS (Common Language Specification) is a set of rules that defines how code written in different .NET-supported languages should be written to be accessible to other languages. It ensures that code written in one language can be used by code written in another language.

What is garbage collection in .NET?

Garbage collection is the automatic memory management process in .NET that releases memory allocated to objects that are no longer used by an application. It allows for more efficient use of memory and reduces the likelihood of memory leaks.

What is a delegate in .NET?

A delegate is a type that represents a reference to a method. It allows methods to be passed as parameters or returned from methods. Delegates are often used for event handling and asynchronous programming.

What is a class in .NET?

A class is a blueprint for creating objects that define the properties and methods of an object. It is a fundamental building block of object-oriented programming.

What is an interface in .NET?

An interface is a set of methods and properties that define a contract for classes that implement it. It allows for polymorphism and abstraction in programming.

What is an abstract class in .NET?

An abstract class is a class that cannot be instantiated and is used as a base class for other classes to inherit from. It may contain abstract methods, which are not implemented in the base class but must be implemented by any derived class.

What is a sealed class in .NET?

A sealed class is a class that cannot be inherited from. It is often used to prevent unintended changes to a class’s behavior.

What is inheritance in .NET?

Inheritance is a mechanism in .NET that allows a class to inherit the properties and methods of another class. It allows for code reuse and promotes modularity in programming.

What is polymorphism in .NET?

Polymorphism is a mechanism in .NET that allows objects to take multiple forms, depending on the context in which they are used. It allows for greater flexibility in programming and promotes code reuse.

What is a namespace in .NET?

A namespace is a way to organize classes and other types in .NET. It helps to prevent naming conflicts and allows for easier navigation and management of large codebases.

What is an assembly in .NET?

An assembly is a collection of types and resources that are built together into a single unit of deployment in .NET. It may include executable code, metadata, and other resources such as images, icons, and configuration files. Assemblies can be deployed as standalone executables or as libraries that can be used by other applications.

What is reflection in .NET?

Reflection is a mechanism in .NET that allows a program to examine and modify the metadata of an assembly at runtime. It allows for dynamic loading of assemblies and can be used to create new objects, invoke methods, and access properties at runtime.

What is the difference between an abstract class and an interface in .NET?

An abstract class can contain concrete methods, while an interface cannot. An abstract class is used when there is a partial implementation of a class, while an interface is used when there is no implementation of a class. or An abstract class can have fields and properties, while an interface cannot.

What is the difference between a value type and a reference type in .NET?

A value type is a type that directly contains its data and is allocated on the stack, while a reference type is a type that contains a reference to its data and is allocated on the heap. Value types include simple types such as integers and floating-point numbers, while reference types include objects, arrays, and strings.

What is LINQ in .NET?

LINQ (Language Integrated Query) is a set of features in .NET that allows for the querying of data from different sources such as databases, XML, and objects. It provides a unified syntax for querying data and is used to improve the productivity of developers.

What is an extension method in .NET?

An extension method is a method that allows developers to add functionality to existing types without modifying the original type. It is defined in a static class and can be called as if it were an instance method of the extended type.

What is a lambda expression in .NET?

A lambda expression is a concise way to define an anonymous function in .NET. It allows for the creation of a function without defining a separate method and can be used to improve code readability and reduce code complexity.

What is a delegate multicast in .NET?

A delegate multicast is a delegate that can have multiple methods assigned to it. When the delegate is invoked, all assigned methods are called in the order they were assigned.

What is the difference between a stack and a heap in .NET?

The stack is a region of memory used for the storage of value types and reference types that are short-lived, while the heap is a region of memory used for the storage of reference types that are long-lived. The stack is managed automatically by the CLR, while the heap must be managed manually.

What is the difference between a string and a StringBuilder in .NET?

A string is an immutable type that cannot be modified after it is created, while a StringBuilder is a mutable type that allows for the dynamic modification of a string. StringBuilder is used when there is a need to concatenate strings or modify the contents of a string frequently.

What is the difference between a struct and a class in .NET?

A struct is a value type that is stored on the stack, while a class is a reference type that is stored on the heap. Structs are used for simple types that contain a few data members, while classes are used for more complex types that require encapsulation and inheritance. Structs are passed by value, while classes are passed by reference.

.NET Interview Questions Preparation Tips

Preparing for a .NET interview can be challenging, but it’s not impossible. Below are some tips to help you prepare for your .NET interview:

  • Review your knowledge of the .NET framework and its components, such as CLR, CTS, and CLS.
  • Brush up on your knowledge of programming languages, including C# and VB.NET.
  • Learn about database programming and SQL Server.
  • Study software development best practices, such as design patterns and SOLID principles.
  • Practice coding exercises and problem-solving..

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Preparing for a .NET interview questions can be challenging, but with the right preparation, it is possible to succeed. By reviewing the key concepts of .NET, such as the CLR, CTS, and CLS, and practicing coding exercises, developers can confidently tackle any .NET interview questions they may encounter.

Understanding the nuances of .NET, including the differences between ASP.NET WebForms and ASP.NET MVC, the uses of delegates, and the benefits of LINQ, will help developers showcase their knowledge and expertise in their next .NET interview.

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