C# Basics

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Table of Contents

• Fundamentals
• Operators
• Classes
• Encapsulation
• Inheritance
• Collections
• Multithreading
• File Handling
• Regular Expression
• Exception Handling
• Events and Delegates
• Garbage Collection
• Lambda Expressions
• LINQ
• Microservices
• Unit Tests
• Design Patterns
• Performance and Optimization
• Deployment
• .NET Core
• Miscellaneous

# 1. FUNDAMENTALS

Q. What is C# and what are its main features?

Q. What is object-oriented programming?

Q. What are the different types of data types available in C#?

Q. Can primitive data types be stored in heap?

Q. Can you store multiple data types in System.Array?

Q. What is an extension method in C# and how is it implemented?

Q. What is a generic type in C# and why is it used?

Q. What is an anonymous method in C# and how is it used?

Q. Can you explain the use of the "this" keyword in C#?

Q. What is the difference between a value type and a reference type in C#?

Q. What is a constructor in C# and what are its different types?

Q. What is the difference between a method and a function in C#?

Q. What is the Common Language Runtime (CLR) in C#?

Q. What is the purpose of namespaces in C#?

Q. What is the purpose of the using statement in C#?

Q. What are properties in C# and how are they used?

Q. What are the Arrays in C#.Net?

Q. What is the difference between the System.Array.CopyTo() and System.Array.Clone()?

Q. What is jagged array in C#.Net?

Q. It is possible to store mixed datatypes such as int, string, float, char all in one array?

Q. How can you sort the elements of the array in descending order?

Q. What is a property in C#?

Q. What is the difference between var and dynamic types?

Q. What is a struct in C#?

Q. What is the difference between abstract and virtual methods?

Q. What is the difference between out and ref parameters?

Q. What is the purpose of the nameof operator in C#?

Q. What is the difference between checked and unchecked contexts?

Q. What is a generic in C#?

Q. What is a Tuple in C#?

Q. What is a namespace in C#?

Q. How are primitive and objects stored in memory?

Q. Explain byval and byref?

Q. Differentiate between copy byvalue and copy byref?

Q. What is NuGet?

Q. What is an immutable string?

Q. What is the JIT compiler process?

Q. Explain the characteristics of value-type variables that are supported in the C# programming language.

Q. What is a parameter? Explain the new types of parameters introduced in C# 4.0.

Q. Briefly explain the characteristics of reference-type variables that are supported in the C# programming language.

Q. What are the different types of literals?

Q. What is the main difference between sub-procedure and function?

Q. How to use extension methods?

Q. What is the difference between string and StringBuilder in C#?

Q. What is difference between late binding and early binding in C#?

Q. What is Indexer in C# .Net?

Q. What are the differences between Object, Var and Dynamic type?

Q. What is the difference between IEnumerable and IQueryable?

Q. What is the difference between managed and unmanaged code?

Q. What is Expression Trees In C#?

Q. What is an Object Pool in .Net?

Q. What are generics in C#.net?

Q. What is Serialization?

Q. Can you explain the difference between lazy and eager evaluation in C#?

Q. Mention the two major categories that distinctly classify the variables of C# programs.

Q. What is checked block and unchecked block?

Q. What is the difference between typeOf() and sizeOf()?

Q. What is widening and Narrowing?

Q. How to view an Assembly?

Q. What are MultiLingual Applications?

Q. What is the use of Codesnippets?

Q. What are dynamic type variables in C#?

Q. Can you describe the process of code compilation in .NET?

Q. What is the difference between ToString() and Convert.ToString()?

Q. What is the difference between int.Parse() and Convert.ToInt32()?

Q. What is the use of Code Snippets?

Q. Write a program to get the range of Byte Datatype?

Q. What are attributes in C# and how can they be used?

Q. What are property Accessors?

Q. Why can't you specify the accessibility modifier for methods inside the interface?

Q. Can you return multiple values from a function in C#?

Q. In how many ways you can pass parameters to a method?

Q. What are Indexers in C#?

Q. How do you implement a custom IComparer for sorting in C#?

Q. How can you improve string concatenation performance in C#?

Q. How do you work with parallelism and concurrency in C#?

Q. What is an indexer in C#?

Q. How are custom controls added to an application in C#?

Q. What is the use of conditional preprocessor directive in C#?

Q. What are pointer types in C#?

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# 2. OPERATORS

Q. How you would use a bitwise operator in C#?

Q. Explain the use of the as operator in C# and the best way to use it?

Q. What is the use of Null Coalescing Operator (??) in C#?

Q. Can you give an example of how to use the is operator and the as operator with inheritance in C#?

Q. Difference between "is" and "as" operator in C#.

Q. What are nullable types in C#?

Q. What is Type Casting and what are its types in C#?

Q. What are operators in C# and can you provide examples?

Q. What is the difference between == operator and .Equals() method?

Q. What is the purpose of the var keyword in C#?

Q. What are the differences between const and readonly keywords?

Q. How does checked and unchecked context affect arithmetic operations?

Q. What is short-circuit evaluation in C#?

Q. List some different ways for equality check in .Net?

Q. How to get the sizeof a datatype in C#?

Q. Asynchronous programming with async, await, Task in C#

Q. What is difference between static, readonly, and constant in C#

Q. How to loop through an enum in C#?

Q. What is NullReferenceException in C#?

Q. How to set default value to Property in C#

Q. How to convert int to enum in C#

Q. What is BigInteger Data Type in C#

Q. How to convert String to Enum in C#

Q. How to convert an Object to JSON in C#

Q. How to convert JSON String to Object in C#

Q. How to Pass or Access Command-line Arguments in C#?

Q. How to convert date object to string in C#?

Q. How to combine two arrays without duplicate values in C#?

Q. How to convert string to int in C#?

Q. What is boxing and unboxing?

Q. Is boxing unboxing good or bad?

Q. Can we avoid boxing and unboxing?

Q. What effect does boxing and unboxing have on performance?

Q. Differentiate between Boxing and Unboxing.

Q. Explain casting, implicit casting and explicit casting ?

Q. What can happen during explicit casting ?

Q. What is the difference between explicit and implicit conversions?

Q. What is the difference between == and ReferenceEquals in C#?

Q. Explain var and dynamic?

Q. What is the difference between constant and readonly in C#?

Q. What is the purpose of the is and as operators in C#?

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# 3. CLASSES

Q. How are static constructors executed in Parent child?

Q. If a base class has a number of overloaded constructors, and an inheriting class has a number of overloaded constructors; can you enforce a call from an inherited constructor to a specific base constructor?

Q. If a base class has a bunch of overloaded constructors, and an inherited class has another bunch of overloaded constructors, can you enforce a call from an inherited constructor to an arbitrary base constructor?

Q. How to access the constructors of one class to another class?

Q. What is the use of static constructors?

Q. Can you explain the difference between a static and an instance method in C#?

Q. What is an abstract class in C# and when is it used?

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

Q. What is reflection in .NET and how would you use it?

Q. When to use reflection and when not in C#?

Q. What is a sealed class in C# and why is it used?

Q. What are the benefits of using a sealed class in C#?

Q. Is it possible for a sealed class to be used as a base class in C#?

Q. Is it possible for a sealed class in C# to define virtual methods?

Q. Is it possible for a non-child class to define sealed methods in C#?

Q. How can abstract classes be used to implement the Template Method design pattern?

Q. Can you give an example of how abstract classes can lead to implementation of anti-patterns such as the God Object pattern?

Q. How can abstract classes be used to implement the Factory Method pattern?

Q. Can you explain the SOLID principle of Single Responsibility and how it relates to abstract classes in C#?

Q. How can abstract classes be used to implement the Dependency Inversion principle?

Q. Can you explain the SOLID principle of Liskov Substitution and how it relates to abstract classes in C#?

Q. What is the difference between an abstract class and a concrete class in C#, and how does this relate to the Open-Closed principle?

Q. Can you give an example of how abstract classes can help to enforce the Interface Segregation principle?

Q. How can abstract classes be used to implement the Strategy design pattern?

Q. Is it possible to declare abstract methods as private in C#?

Q. Is it possible for an abstract class to contain a main method in C#?

Q. Is it possible in C# that a class inherit from multiple abstract classes?

Q. What is the difference between a sealed class and an unsealed class in C#?

Q. How can you use a sealed class to prevent inheritance in C#?

Q. Can we do Multiple inheritance with Abstract classes?

Q. Whats the difference between Abstract class and interface?

Q. Why simple base class replace Abstract class?

Q. What are nested classes and when to use them?

Q. Can Nested class access outer class variables?

Q. Can we have public, protected access modifiers in nested class?

Q. Are private class members inherited to the derived class?

Q. Where is a protected class-level variable available?

Q. Are private class-level variables inherited?

Q. Which class is at the top of .NET class hierarchy?

Q. What is the .NET collection class that allows an element to be accessed using a unique key?

Q. Explain the three services model commonly know as a three-tier application?

Q. Can you prevent your class from being inherited by another class?

Q. Can you allow a class to be inherited, but prevent the method from being over-ridden?

Q. When do you absolutely have to declare a class as abstract?

Q. What is the implicit name of the parameter that gets passed into the set method/property of a class?

Q. When you inherit a protected class-level variable, who is it available to?

Q. Are private class-level variables inherited?

Q. What is the top .NET class that everything is derived from?

Q. When do you absolutely have to declare a class as abstract (as opposed to free-willed educated choice or decision based on UML diagram)?

Q. Is it namespace class or class namespace?

Q. What is the default Access Modifier for the members of the class?

Q. How to Call the Default constructor of one class with the parameterized constructor of same class?

Q. What is scope of a Protected Internal member variable of a C# class?

Q. What is the difference between Virtual method and Abstract method?

Q. What is scope of a Internal member variable of a C# class?

Q. How would you implement multiple interfaces with the same method name in the same class?

Q. How can you create a derived class object from a base class?

Q. Which is the parent class of all classes which we create in C#?

Q. What is the base class in .NET framework from which all the classes have been developed?

Q. How do you implement a custom attribute in C#?

Q. What is the System. String and System.Text.StringBuilder classes?

Q. What are I/O classes in C#?

Q. Can you add extension methods to an existing static class?

Q. Can you create sealed abstract class in C#?

Q. Can you inherit multiple interfaces?

Q. What interface should your data structure implement to make the "Where" method work?

Q. Can we define methods as private in interface?

Q. If i want to change interface whats the best practice?

Q. Can we create instance of interface?

Q. Explain the differences between covariance and contravariance in C# for delegates and interfaces.

Q. What is an abstraction?

Q. Is it compulsory to implement Abstract methods?

Q. What is the method MemberwiseClone() doing?

Q. Explain the difference between destructor, dispose and finalize method?

Q. Could you explain the difference between Func vs. Action vs. Predicate?

Q. What is a namespace and is it compulsory?

Q. What do you think about empty destructor?

Q. What are the different types of "USING/HAS A" relationship?

Q. Differentiate between Composition vs Aggregation vs Association?

Q. What are circular references?

Q. What is weak reference in C#?

Q. Explain weak and strong references?

Q. How can you use Interfaces in C# to reduce coupling and improve maintainability?

Q. What happens if the inherited interfaces have conflicting method names?

Q. What is the purpose of the volatile keyword in C#?

Q. What is the purpose of the checked keyword in C#?

Q. What is the purpose of the this keyword in C#?

Q. What is the purpose of the base keyword in C#?

Q. What is the purpose of the default keyword in C#?

Q. What is the purpose of the params keyword in C#?

Q. What is the purpose of the yield keyword in C#?

Q. What is the async and await keyword in C#?

Q. What is the difference between override and new keywords?

Q. Why do we need the out keyword ?

Q. What is the params keyword in C#?

Q. What is the purpose of the yield keyword in C#? Provide an example of using it with an iterator?

Q. What is the "yield" keyword used for in C#?

Q. What is the importance of "this" keyword?

Q. What is the difference between ref and out keywords?

Q. What is a partial class in C#?

Q. What is a static class in C#?

Q. What is a sealed class in C#?

Q. What are the different types of classes in C#?

Q. What is an Abstract Class?

Q. Are private class members inherited to the derived class?

Q. What are partial classes?

Q. What is the difference between a struct and a class in C#?

Q. What is the difference between public, private, protected, and internal access modifiers?

Q. C# provides a default constructor for me. I write a constructor that takes a string as a parameter, but want to keep the no parameter one. How many constructors should I write?

Q. Why do we need constructors?

Q. In parent child which constructor fires first?

Q. What is the Constructor Chaining in C#?

Q. What are the different Ways of method can be overloaded?

Q. When and why to use method overloading?

Q. Is operator overloading supported in C#?

Q. Can "this" be used within a static method?

Q. Can you declare an override method to be static if the original method is not static?

Q. Can you declare the override method static while the original method is non-static?

Q. Why can you have only one static constructor?

Q. When does static constructor fires?

Q. When the static constructor will be called?

Q. Can we declare Public access modifier for static constructor?

Q. If we declare Main() and static constructor in the same class which one will be called first?

Q. How does dependency inversion benefit, show with an example?

Q. Will only Dependency inversion solve decoupling problem?

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# 4. ENCAPSULATION

Q. What is encapsulation in C# and why is it important?

Q. How do you implement encapsulation in C#?

Q. Can you provide an example of encapsulation in C#?

Q. What are the benefits of using encapsulation in object-oriented programming?

Q. How does encapsulation help in maintaining code?

Q. What is the difference between encapsulation and abstraction in C#?

Q. How can encapsulation be violated in C#?

Q. How do access modifiers (public, private, protected, internal) relate to encapsulation in C#?

Q. Explain method hiding?

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# 5. INHERITANCE

Q. What is inheritance in C# and how does it work?

Q. What is the difference between single inheritance and multiple inheritance in C#?

Q. How can you use the "base" keyword in C# to call the base class constructor?

Q. Can you explain polymorphism and how it is achieved in C#?

Q. How can you use inheritance and polymorphism together to achieve dynamic dispatch in C#?

Q. What is the purpose of the base keyword in C#, and how is it used in inheritance?

Q. What are the differences between virtual methods and abstract methods in C#, and when each should be used?

Q. How do you handle constructor inheritance in C#, and what is the role of the base keyword in constructor inheritance?

Q. What is the difference between inheritance and composition in C# and when should you use each one?

Q. Can you override private virtual methods?

Q. What does the keyword virtual mean in the method definition?

Q. What is a Virtual Method in C#?

Q. Why a private virtual method cannot be overridden in C#?

Q. How do you override a method in C#?

Q. What is the difference between override and new keywords in C#?

Q. How does inheritance promote code reusability?

Q. What are the potential pitfalls of using inheritance?

Q. How do you prevent a class from being inherited in C#?

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# 6. COLLECTIONS

Q. What are collections in C# and why are they used?

Q. What is the difference between an array and a collection in C#?

Q. What are the different types of collections available in C#?

Q. What are Concurrent Collection Classes?

Q. Explain Hashtable in C#?

Q. What is IEnumerable<> in C#?

Q. What is the difference between a BlockingCollection and a ConcurrentQueue or ConcurrentStack? In which scenarios would you choose to use the BlockingCollection, and why?

Q. Explain the difference between IQueryable, ICollection, IList & IDictionary interfaces?

Q. What is difference between Hashtable and Dictionary?

Q. What is difference between SortedList and SortedDictionary in C#?

Q. What is the difference between Array and ArrayList?

Q. Whose performance is better array or arraylist?

Q. What class is underneath the Sorted List class?

Q. IEnumerable vs List - What to Use? How do they work?

Q. When to use ArrayList over array[] in C#?

Q. What are the differences between IEnumerable and IQueryable?

Q. How to sort the generic SortedList in the descending order?

Q. What is a HashSet and when would you use it?

Q. How is LinkedList used in C#?

Q. What is difference between Stack and Heap?

Q. Are string allocated on stack or heap?

Q. How many stack and heaps are created for an application?

Q. How are stack and heap memory deallocated?

Q. Who clears the heap memory?

Q. Where is structure allocated Stack or Heap?

Q. Can structures get created on Heap?

Q. Is there a way we can see this Heap memory?

Q. Explain stack and Heap?

Q. Where are stack and heap stored?

Q. What goes on stack and what goes on heap?

Q. How is the stack memory address arranged?

Q. How is stack memory deallocated LIFO or FIFO?

Q. How do you choose between List<T> and ArrayList in C#?

Q. How do you iterate over a collection in C#?

Q. What is the difference between IEnumerable and ICollection in C#?

Q. How do you sort a collection in C#?

Q. How do you remove duplicates from a collection in C#?

Q. What is the difference between Queue and Stack in C#?

Q. How do you convert an array to a collection in C#?

Q. What are the thread-safe collection classes available in C#?

Q. How do you use LINQ with collections in C#?

Q. What is the difference between Array and List in C#?

Q. What is the difference between Array and Collections?

Q. What are generic collections?

Q. How can you optimize memory usage and performance when working with large data collections in C#?

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# 7. MULTITHREADING

Q. What is multithreading in C# and why is it important?

Q. How do you create a new thread in C#?

Q. What is the difference between a thread and a process?

Q. How do you synchronize threads in C#?

Q. What is the ThreadPool class and how is it used?

Q. What are Task and async/await in C#?

Q. How do you handle exceptions in multithreaded applications?

Q. What is a deadlock and how can it be avoided?

Q. What is the purpose of the lock statement in C#?

Q. What is the difference between Monitor and lock in C#?

Q. How do you use the Monitor class for thread synchronization?

Q. What is the difference between Thread.Join and Thread.Sleep?

Q. How do you implement a producer-consumer scenario in C#?

Q. What is the CancellationToken and how is it used in multithreading?

Q. How do you use Concurrent collections in C#?

Q. What is the difference between Parallel.For and Task.Run?

Q. What are the advantages and disadvantages of multithreading?

Q. Why does a delegate need to be passed as a parameter to the Thread class constructor?

Q. How to pass the parameter in Thread?

Q. Why do we need a ParameterizedThreadStart delegate?

Q. When to use ParameterizedThreadStart over ThreadStart delegate?

Q. How to pass data to the thread function in a type-safe manner?

Q. How to retrieve the data from a thread function?

Q. What is the difference between Threads and Tasks?

Q. What is the Significance of Thread.Join and Thread.IsAlive functions in multithreading?

Q. What happens if shared resources are not protected from concurrent access in a multithreaded program?

Q. How do protect shared resources from concurrent access?

Q. Which option is better?

Q. What are the Interlocked functions?

Q. What is AutoResetEvent and how it is different from ManualResetEvent?

Q. What is the Semaphore?

Q. What is Mutex and how it is different from other Synchronization mechanisms?

Q. What is the Race condition?

Q. What is the volatile keyword?

Q. How can you share data between multiple threads?

Q. What is synchronization and why it is important?

Q. Can you count some names of Synchronization primitives?

Q. What are the four necessary conditions for Deadlock?

Q. What is LiveLock?

Q. In the context of C# multithreading, what are the main differences between the ThreadPool and creating your own dedicated Thread instances?

Q. How can you ensure mutual exclusion while accessing shared resources in C# multithreading without using lock statement or Monitor methods?

Q. Explain the difference between the Barrier and CountdownEvent synchronization primitives in multithreading. Provide a real-world scenario in which each of these would be useful.

Q. What would be the potential issues with using Thread.Abort() to terminate a running thread? Explain the implications and suggest alternative methods for gracefully stopping a thread.

Q. How do you achieve thread synchronization using ReaderWriterLockSlim in C# multithreading? Explain its advantages over traditional ReaderWriterLock.

Q. How do Tasks in C# differ from traditional Threads? Explain the benefits and scenarios where Tasks would be preferred over directly spawning Threads.

Q. Discuss the differences between Volatile, Interlocked, and MemoryBarrier methods for using shared variables in multithreading. When should each of these be used?

Q. In C# multithreading, explain the concept of thread-local and data partitioning and how it can help improve the overall performance of a multi-threaded application.

Q. How does the Cancellation model in a Task Parallel Library work? Explain how you can use CancellationToken to handle cancellations in TPL.

Q. How do you combine asynchronous programming with multithreading using C#'s async/await pattern? Explain how the TaskScheduler class can be used in this context.

Q. What is parallelism, and how do you control the degree of parallelism for a parallel loop in C# using the Parallel class?

Q. Describe the concept of lock contention in multithreading and explain its impact on the performance of your application. How can you address and mitigate lock contention issues?

Q. How do Tasks in C# differ from traditional Threads? Explain the benefits and scenarios where Tasks would be preferred over directly spawning Threads.

Q. Describe the concept of a race condition in C# multithreading and explain different strategies for preventing race conditions from occurring in your application.

Q. What is lazy initialization in C# multithreading and how does it affect application start-up performance?

Q. How do you achieve thread synchronization using ReaderWriterLockSlim in C# multithreading? Explain its advantages over traditional ReaderWriterLock.

Q. What are the differences between ManualResetEvent and AutoResetEvent synchronization primitives in C# multithreading?

Q. Explain the use of SpinLock in C# multithreading and how it differs from a standard lock or Monitor. Describe the potential advantages and limitations of using SpinLocks.

Q. What is Multithreading with .NET?

Q. How can you implement multithreading in C#?

Q. When should multithreading be used and when should it be avoided in C#?

Q. What is difference between lock and interlock in Multithreading C#?

Q. How does multithreading improve the performance over a single thread solution?

Q. How do you handle deadlocks in multi-threaded C# applications?

Q. What is the difference between lock and Monitor in C#?

Q. What is a thread in C#?

Q. What is the purpose of the ThreadPool class in C#?

Q. What is the difference between Task.Run and Task.Factory.StartNew?

Q. What is the difference between Task and Thread in C#?

Q. What is the purpose of the lock statement in C#?

Q. Explain the concept of threading in .NET.

Q. What is Thread Pooling in C#?

Q. What are the different states of a Thread in C#?

Q. What is the difference between Task and Thread in C#?

Q. What is the lock statement in C#?

Q. How are threads different from TPL ?

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# 8. FILE HANDLING

Q. What is File Handling in C#.Net?

Q. How do you read a file in C#?

Q. How do you write to a file in C#?

Q. What is the difference between File.ReadAllText and File.ReadAllLines in C#?

Q. How do you append text to an existing file in C#?

Q. How do you check if a file exists in C#?

Q. What is the purpose of the StreamReader and StreamWriter classes in C#?

Q. How do you handle exceptions when working with files in C#?

Q. How do you delete a file in C#?

Q. What is the difference between FileStream and MemoryStream in C#?

Q. How do you copy a file in C#?

Q. How do you move a file in C#?

Q. What is the FileInfo class and how is it used?

Q. How do you read and write binary files in C#?

Q. How do you work with directories in C#?

Q. How do you get the size of a file in C#?

Q. What are DLL files, and what are the advantages of using them?

Q. What is a MemoryStream in C#?

Q. What is the purpose of the FileStream class in C#?

Q. What is the difference between StreamReader and StreamWriter?

Q. What is a BinaryReader in C#?

Q. What is the purpose of the BinaryWriter class in C#?

Q. What is the difference between TextReader and TextWriter?

Q. What is a StringReader in C#?

Q. What is the purpose of the StringWriter class in C#?

Q. What is the difference between XmlReader and XmlWriter?

Q. What is a JsonReader in C#?

Q. What is the purpose of the JsonWriter class in C#?

Q. What is the difference between DataContractSerializer and XmlSerializer?

Q. What is a BinaryFormatter in C#?

Q. What is the purpose of the SoapFormatter class in C#?

Q. What is the difference between BinaryFormatter and SoapFormatter?

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# 9. REGULAR EXPRESSION

Regular Expression

Q. What is a regular expression in C# and what is it used for?

Q. How do you create a regular expression in C#?

Q. What is the purpose of the Regex class in C#?

Q. How do you match a pattern in a string using regular expressions in C#?

Q. How do you replace text in a string using regular expressions in C#?

Q. What are some common use cases for regular expressions in C#?

Q. How do you validate an email address using regular expressions in C#?

Q. What is the difference between Regex.Match and Regex.IsMatch in C#?

Q. How do you extract groups from a match using regular expressions in C#?

Q. How do you handle case sensitivity in regular expressions in C#?

Q. How to create precompiled Regex object in .Net?

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# 10. EXCEPTION HANDLING

Q. What is exception handling in C# and why is it important?

Q. How do you handle exceptions in C#?

Q. What is the difference between try, catch, and finally blocks in C#?

Q. How do you create a custom exception in C#?

Q. What is the purpose of the throw keyword in C#?

Q. How do you rethrow an exception in C#?

Q. What is the difference between throw and throw ex in C#?

Q. How do you handle multiple exceptions in a single catch block in C#?

Q. What is the Exception class in C# and what are its key properties?

Q. How do you log exceptions in C#?

Q. What is the InnerException property in C#?

Q. How do you use the using statement to handle exceptions in C#?

Q. What is the difference between checked and unchecked exceptions in C#?

Q. How do you handle exceptions in asynchronous methods in C#?

Q. What is the AggregateException class in C# and when is it used?

Q. What is difference between Throw Exception and Throw Clause.

Q. How do you handle exceptions in a method that returns a Task?

Q. Which class acts as a base class for all exceptions in C#?

Q. Will the finally block get executed if an exception has not occurred?

Q. What is the C# syntax to catch any possible exception?

Q. What is the difference between System.ApplicationException class and System.SystemException class?

Q. In try block if we add return statement whether finally block is executed in C#?

Q. What is the difference between StackOverflowError and OutOfMemoryError?

Q. Name different types errors which can occur during the execution of a program?

Q. Explain the difference between "finally" and "finalize block"?

Q. What is the difference between "throw" and "throw ex"

Q. Can Multiple Catch Blocks executed in C#?

Q. What is the role of System.Exception class?

Q. List down the most commonly used types of exceptions in .NET?

Q. What is the difference between throw and throw new in C#?

Q. What are the different ways to handle errors in C#?

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# 11. EVENTS AND DELEGATES

Q. What are Events?

Q. What are delegates in C# and why are they used?

Q. What is the difference between a delegate and an event in C#?

Q. How do you declare and raise an event in C#?

Q. What is the purpose of the EventHandler delegate in C#?

Q. How do you subscribe to and unsubscribe from an event in C#?

Q. What is a multicast delegate in C#?

Q. How do you use anonymous methods with delegates in C#?

Q. What are the advantages of using events and delegates in C#?

Q. How do you use lambda expressions with delegates in C#?

Q. What is the difference between Action, Func, and Predicate delegates in C#?

Q. How do you implement custom event accessors in C#?

Q. What is the event keyword in C# and how is it used?

Q. How do you handle events in a derived class in C#?

Q. What are the best practices for using events and delegates in C#?

Q. What is an event in C# and how does it work?

Q. What is an event in C# and how is it different from a delegate?

Q. What is a delegate in C# and how is it related to events?

Q. What are called combinable delegates?

Q. How to use delegates with Events?

Q. What is the difference between Event and Method?

Q. What is the difference between lambdas and delegates?

Q. What is the difference between Func<string,string> and delegate?

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# 12. GARBAGE COLLECTION

Q. What is garbage collection in .NET?

Q. Explain the role of the garbage collector in .NET.

Q. How do you manage memory in .NET applications?

Q. How does garbage collection work in .NET and how can you optimize it?

Q. How does the garbage collector know when to clean up objects?

Q. Does the garbage collector clean up primitive types?

Q. What are Generation 0, Generation 1, and Generation 2 in garbage collection?

Q. How does the garbage collector behave when a class has a destructor?

Q. Explain the importance of the garbage collector.

Q. Can the garbage collector reclaim unmanaged objects?

Q. Can the garbage collector clean up unmanaged code?

Q. Can you force garbage collection in .NET?

Q. Is it a good practice to force garbage collection?

Q. How do you detect memory leaks in .NET applications?

Q. What is GC0, GC1, and GC2?

Q. How does GC behave when we have a destructor?

Q. What is a Mutex in C#?

Q. What is the purpose of the Semaphore class in C#?

Q. What is the difference between Semaphore and SemaphoreSlim?

Q. What is a deadlock in C#?

Q. What is the purpose of the Interlocked class in C#?

Q. What is the difference between Task and ValueTask?

Q. What is a CancellationToken in C#?

Q. What is the purpose of the CancellationTokenSource class in C#?

Q. What is the difference between Task.WhenAll and Task.WhenAny?

Q. What is a ConcurrentDictionary in C#?

Q. What is the purpose of the BlockingCollection class in C#?

Q. What is the difference between ConcurrentBag and ConcurrentQueue?

Q. What is a MemoryCache in C#?

Q. What is the purpose of the Lazy class in C#?

Q. What is the difference between Lazy and Lazy<T>?

Q. What is a WeakReference in C#?

Q. What is the purpose of the GC.Collect method in C#?

Q. What is the difference between GC.Collect and GC.WaitForPendingFinalizers?

Q. What is a finalizer in C#?

Q. What is the purpose of the GC.SuppressFinalize method in C#?

Q. What is the difference between GC.KeepAlive and GC.ReRegisterForFinalize?

Q. What is garbage collection and how does it work in .NET Core?

Q. How do you optimize garbage collection in .NET Core?

Q. What is the difference between server and workstation garbage collection?

Q. How do you use the GCSettings class to configure garbage collection?

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# 13. LAMBDA EXPRESSIONS

Q. What is a lambda expression in C# and why is it used?

Q. How do you declare a lambda expression in C#?

Q. What is the difference between a lambda expression and an anonymous method in C#?

Q. How do you use lambda expressions with LINQ in C#?

Q. Can you provide an example of a simple lambda expression in C#?

Q. What are the advantages of using lambda expressions in C#?

Q. How do you capture variables in a lambda expression in C#?

Q. What is the difference between statement lambdas and expression lambdas in C#?

Q. How do you use lambda expressions with delegates in C#?

Q. What are the limitations of lambda expressions in C#?

Q. How do you handle exceptions in lambda expressions in C#?

Q. Can you use async/await with lambda expressions in C#?

Q. How do you use lambda expressions in event handling in C#?

Q. What is the syntax for a lambda expression with multiple parameters in C#?

Q. How do you use lambda expressions with generic types in C#?

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# 13. LINQ

Q. What is LINQ in C# and why is it used?

Q. What are the main advantages of using LINQ in C#?

Q. How do you write a basic LINQ query in C#?

Q. What is the difference between LINQ to Objects, LINQ to SQL, and LINQ to XML?

Q. Can you provide an example of a LINQ query that filters and sorts data?

Q. What are the different types of LINQ operators in C#?

Q. How do you use the Select and Where operators in LINQ?

Q. What is the purpose of the GroupBy operator in LINQ?

Q. How do you perform a join operation using LINQ?

Q. What is the difference between deferred execution and immediate execution in LINQ?

Q. How do you use the Aggregate operator in LINQ?

Q. What is the Let keyword in LINQ and how is it used?

Q. How do you handle null values in LINQ queries?

Q. What are anonymous types in LINQ and how are they used?

Q. How do you use LINQ with collections in C#?

Q. How do you optimize LINQ queries for performance?

Q. Explain the differences between Parallel.ForEach and PLINQ (Parallel LINQ)?

Q. How does LINQ's "Where" method works?

Q. What are the benefits of a Deferred Execution in LINQ?

Q. Can you explain the difference between a query expression and a method chain in LINQ?

Q. Can you give an example of using LINQ to filter data in a collection?

Q. How can LINQ be used to perform grouping and aggregation operations on data?

Q. How does the Single Responsibility Principle (SRP) apply to LINQ code?

Q. Can you demonstrate the use of LINQ to implement the Open-Closed Principle (OCP)?

Q. How does the Liskov Substitution Principle (LSP) apply to LINQ code?

Q. Can you give an example of using LINQ to implement the Interface Segregation Principle (ISP)?

Q. Can you explain the Dependency Inversion Principle (DIP) and how it relates to LINQ code?

Q. Explain the difference between Select and Where?

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# 15. MICROSERVICES

Q. What are microservices and why are they used?

Q. How do you implement microservices in .NET Core?

Q. What are the main advantages of using microservices architecture?

Q. How do you handle communication between microservices in .NET Core?

Q. What is the role of API Gateway in microservices architecture?

Q. How do you manage data consistency in microservices?

Q. What are some common challenges when working with microservices?

Q. How do you deploy microservices in a containerized environment?

Q. What is the purpose of service discovery in microservices?

Q. How do you implement logging and monitoring in microservices?

Q. What is the difference between monolithic and microservices architecture?

Q. How do you handle security in microservices?

Q. What is the role of Docker in microservices?

Q. How do you implement resilience and fault tolerance in microservices?

Q. What are some best practices for designing microservices?

Q. Name the key components of Microservices?

Q. What are the tools commonly used tools for Microservices?

Q. What are the key principles to follow when designing microservices?

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# 16. UNIT TESTS

Q. What is unit testing and why is it important for writing high-quality code?

Q. How do you write a unit test in C#?

Q. What is the difference between unit testing and integration testing?

Q. What frameworks are commonly used for unit testing in C#?

Q. What is the purpose of mocking in unit testing?

Q. How do you use Moq framework for mocking in C#?

Q. What are the best practices for writing unit tests?

Q. How do you run unit tests in Visual Studio?

Q. What is code coverage and how do you measure it?

Q. How do you handle dependencies in unit tests?

Q. What is the Arrange-Act-Assert (AAA) pattern in unit testing?

Q. What is the difference between TestInitialize and ClassInitialize in MSTest?

Q. How do you use data-driven tests in C#?

Q. Can you explain the different types of unit tests that can be performed in C#?

Q. How do you use the xUnit framework to write and run unit tests in C#?

Q. Can you explain how to write a test case for checking the exception handling in C#?

Q. How do you use mock objects to test code in isolation from its dependencies in C#?

Q. Can you explain the difference between unit tests and integration tests, and when to use each type of test?

Q. Can you describe the process of test-driven development (TDD) and how it can be applied to C# development?

Q. How do you measure the code coverage of your unit tests, and what is considered an acceptable level of code coverage in C#?

Q. How to use dependency injection to make code more testable in C#?

Q. What is xUnit and why is it used for unit testing in C#?

Q. How do you write a basic unit test using xUnit?

Q. What is the difference between xUnit and other testing frameworks like MSTest and NUnit?

Q. How do you set up xUnit in a .NET Core project?

Q. How do you use the [Fact] attribute in xUnit?

Q. What is the purpose of the [Theory] attribute in xUnit?

Q. How do you use InlineData with [Theory] in xUnit?

Q. How do you handle test initialization and cleanup in xUnit?

Q. What is the role of Assert class in xUnit?

Q. How do you run xUnit tests from the command line?

Q. How do you use dependency injection in xUnit tests?

Q. How do you mock dependencies in xUnit tests?

Q. How do you test asynchronous methods using xUnit?

Q. How do you group and order tests in xUnit?

Q. What are some best practices for writing xUnit tests?

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# 17. DESIGN PATTERNS

Q. What are design patterns and why are they important in software development?

Q. Can you explain the Singleton pattern and provide an example in C#?

Q. What is the Factory Method pattern and how is it implemented in C#?

Q. How does the Observer pattern work and when would you use it?

Q. What is the difference between the Adapter and Decorator patterns?

Q. How do you implement the Strategy pattern in C#?

Q. What is the purpose of the Dependency Injection pattern?

Q. Can you explain the Repository pattern and its benefits?

Q. How does the Command pattern work and when should it be used?

Q. What is the difference between the Prototype and Builder patterns?

Q. Can you provide an example of the Template Method pattern in C#?

Q. How does the State pattern help in managing object states?

Q. What are the benefits of using the Composite pattern?

Q. Can you explain the Open-Closed Principle in C#, and provide an example of how it can be implemented in code?

Q. Can you explain the SOLID design principles and how they relate to writing maintainable code?

Q. Can you explain the Single Responsibility Principle in your own words, and how it applies to C# code?

Q. How would you refactor C# code that is tightly coupled between multiple classes?

Q. How do you avoid Primitive Obsession when designing C# classes, and what are the benefits of doing so?

Q. What are design patterns in C# and why are they important?

Q. Can you describe the difference between Structural and Behavioral design patterns in C#, and provide an example of each?

Q. What is the difference between a design pattern and a Architecture Pattern?

Q. Can you please tell me what is the Observer Pattern in C# and how does it work?

Q. How can you use the Decorator Pattern in C# to extend the behavior of an object dynamically?

Q. Can you explain the use of the builder pattern for constructing complex objects?

Q. What is the Prototype pattern in C# and how does it differ from the Factory Method pattern?

Q. How can you use the Facade pattern in C# to simplify a complex system?

Q. What is the adaptor pattern in C# and how is it used to integrate with existing systems?

Q. What is the Flyweight pattern in C# and how is it used to optimize memory usage?

Q. Can you explain the use of the Bridge pattern in C# to separate the abstraction from its implementation?

Q. What is the Chain of Responsibility pattern in C# and how is it used to handle events in a loosely coupled manner?

Q. How can you use the Mediator pattern in C# to reduce coupling between objects?

Q. What is the Interpreter pattern in C# and how is it used for language interpretation?

Q. Explain the Dispose Pattern?

Q. What is CQRS pattern in C#?

Q. Can you explain LISKOV Principle and it's violation?

Q. How can we fix LISKOV Problem?

Q. Is there a connection between LISKOV and ISP?

Q. How can you write code that follows the DRY (Don't Repeat Yourself) principle in C#?

Q. What are some common anti-patterns in C# and how can they be avoided to write clean code?

Q. Explain SRP with an example?

Q. Explain OCP with an example?

Q. What is higher level module and lower level module?

Q. Why do developers move object creation outside high level module?

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# 18. PERFORMANCE AND OPTIMIZATION

Q. What are some common performance issues in .NET Core applications?

Q. How do you measure the performance of a .NET Core application?

Q. What tools are available for profiling .NET Core applications?

Q. How do you use the dotnet-counters tool to monitor performance?

Q. What is the dotnet-trace tool and how is it used?

Q. How do you use the dotnet-dump tool to collect and analyze memory dumps?

Q. What is the dotnet-gcdump tool and how is it used?

Q. How do you optimize memory usage in .NET Core applications?

Q. What are some best practices for managing memory in .NET Core?

Q. How do you reduce the memory footprint of a .NET Core application?

Q. How do you optimize CPU usage in .NET Core applications?

Q. What are some best practices for optimizing CPU-bound operations?

Q. How do you use asynchronous programming to improve performance in .NET Core?

Q. What is the async and await keywords and how are they used?

Q. How do you use the Task class to perform asynchronous operations?

Q. How do you optimize I/O operations in .NET Core applications?

Q. What are some best practices for optimizing disk and network I/O?

Q. How do you use caching to improve performance in .NET Core applications?

Q. What is the IMemoryCache interface and how is it used?

Q. How do you use distributed caching in .NET Core?

Q. What is the IDistributedCache interface and how is it used?

Q. How do you use the ResponseCaching middleware to cache responses?

Q. How do you optimize database access in .NET Core applications?

Q. How do you use connection pooling to improve database performance?

Q. How do you use the AsNoTracking method to optimize query performance?

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# 19. DEPLOYMENT

Q. How do you deploy a .NET Core application to Azure?

Q. What is the dotnet publish command and how is it used?

Q. How do you deploy a .NET Core application to IIS?

Q. What is the WebHostBuilder class and how is it used?

Q. What is the Azure App Service and how is it used?

Q. How do you use Docker to containerize a .NET Core application?

Q. How do you create a Dockerfile for a .NET Core application?

Q. How do you deploy a .NET Core application using Docker?

Q. What is Kubernetes and how is it used with .NET Core applications?

Q. How do you use CI/CD pipelines to deploy .NET Core applications?

Q. What is the Azure DevOps service and how is it used for deployment?

Q. How do you configure a build pipeline in Azure DevOps?

Q. How do you configure a release pipeline in Azure DevOps?

Q. How do you use GitHub Actions for deploying .NET Core applications?

Q. What is the Octopus Deploy tool and how is it used?

Q. What are the best practices for deploying .NET Core applications?

Q. What are the different types of hosting models available in .NET Core?

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# 20. .NET Core

Q. What is .NET Core?

Q. What are the main differences between .NET Framework and .NET Core?

Q. What is the .NET Standard?

Q. How do you handle configuration in a .NET Core application?

Q. What is the .NET Core CLI and how is it used?

Q. How do you create a new .NET Core project?

Q. What is the purpose of the Program.cs and Startup.cs files in a .NET Core application?

Q. How do you identify duplicated code in C#, and what techniques can be used to remove it?

Q. What is Kestrel?

Q. What is Dependency Injection in .NET Core?

Q. How do you handle configuration in .NET Core?

Q. How do you add services to the dependency injection container?

Q. What is the difference between IServiceCollection and IServiceProvider?

Q. How do you configure logging in .NET Core?

Q. How do you perform database migrations in EF Core?

Q. What is the difference between AddTransient, AddScoped, and AddSingleton?

Q. How do you create a RESTful API in ASP.NET Core?

Q. How do you read configuration values from appsettings.json?

Q. What is the IConfiguration interface?

Q. What is the IApplicationBuilder interface?

Q. How do you use middleware in ASP.NET Core?

Q. What is the UseEndpoints method?

Q. How do you create a custom middleware?

Q. What is the ConfigureServices method?

Q. What is the Configure method?

Q. How do you use dependency injection in controllers?

Q. What is the ControllerBase class?

Q. How do you return JSON from a controller action?

Q. What is the ActionResult class?

Q. What is attribute routing?

Q. How do you create a custom route?

Q. What is the HttpGet attribute?

Q. What is the HttpPost attribute?

Q. How do you handle form submissions in ASP.NET Core?

Q. What is model binding?

Q. How do you validate models in ASP.NET Core?

Q. What is the ModelState property?

Q. How do you use data annotations for validation?

Q. What is the ViewResult class?

Q. How do you return a view from a controller action?

Q. What is Razor syntax?

Q. How do you create a Razor view?

Q. What is the _ViewStart.cshtml file?

Q. What is the _Layout.cshtml file?

Q. How do you use partial views in ASP.NET Core?

Q. What is the ViewComponent class?

Q. How do you create a view component?

Q. What is the TagHelper class?

Q. How do you create a custom tag helper?

Q. How do you use the HtmlHelper class in a view?

Q. What is the UrlHelper class?

Q. How do you use the UrlHelper class in a view?

Q. What is the IActionResult interface?

Q. How do you use the IActionResult interface in a controller action?

Q. What is the JsonResult class?

Q. How do you return a JSON result from a controller action?

Q. What is the ContentResult class?

Q. How do you return a content result from a controller action?

Q. What is the FileResult class?

Q. How do you return a file result from a controller action?

Q. What is the RedirectResult class?

Q. How do you return a redirect result from a controller action?

Q. What is the StatusCodeResult class?

Q. How do you return a status code result from a controller action?

Q. What is the ChallengeResult class?

Q. How do you return a challenge result from a controller action?

Q. What is the SignInResult class?

Q. How do you return a sign-in result from a controller action?

Q. What is the SignOutResult class?

Q. How do you return a sign-out result from a controller action?

Q. What is the ForbidResult class?

Q. How do you return a forbid result from a controller action?

Q. What is the LocalRedirectResult class?

Q. How do you return a local redirect result from a controller action?

Q. What is the PartialViewResult class?

Q. How do you return a partial view result from a controller action?

Q. What is the ViewComponentResult class?

Q. How do you return a view component result from a controller action?

Q. What is the PhysicalFileResult class?

Q. How do you return a physical file result from a controller action?

Q. What is the VirtualFileResult class?

Q. How do you return a virtual file result from a controller action?

Q. What is the FileStreamResult class?

Q. How do you return a file stream result from a controller action?

Q. What is the FileContentResult class?

Q. How do you return a file content result from a controller action?

Q. What is the FilePathResult class?

Q. How do you return a file path result from a controller action?

Q. What is the PhysicalFileProvider class?

Q. How do you use the PhysicalFileProvider class?

Q. What is the CompositeFileProvider class?

Q. How do you use the CompositeFileProvider class?

Q. What is the ManifestEmbeddedFileProvider class?

Q. How do you use the ManifestEmbeddedFileProvider class?

Q. What is the EmbeddedFileProvider class?

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# 20. MISCELLANEOUS

Q. What is marshalling and why do we need it?

Q. Query Geolocation & proxy data in .NET using IP2Location

Q. How to calculate the code execution time in C#?

Q. What is the distinction between directcast and ctype?

Q. Explain how to implement a custom serializer and deserializer for a complex object in C#?

Q. Explain the differences between Memory and Span in C#. When would you use one over the other?

Q. What is a DTO?

Q. What does POCO mean?

Q. Define Parsing? Explain how to Parse a DateTime String?

Q. What is IL (Intermediate Language) Code?

Q. What is the use of JIT (Just in time compiler)?

Q. Is it possible to view IL code?

Q. What is the benefit of compiling into IL code?

Q. What is the importance of CTS?

Q. How are initializers executed?

Q. What is Shadowing?

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