Here, We see C# LinkedIn Skill Assessment Answer. This assessment test consists of 15-20 MCQs to demonstrate your knowledge of your selected skills. MCQs come from different topics – C# Assemblies and Extensions, C# Communication, C# Fundamentals, C# Networking, C# Objects, and Types.

C# LinkedIn Skill Assessment Answer :
Q1. In which of these situations are interfaces better than abstract classes?
- When you need to define an object type’s characteristics, use an interface. When you need to define an object type’s capabilities, use an abstract class.
- Interfaces are a legacy of older versions of C#, and are interchangeable with the newer abstract class feature.
- When you need a list of capabilities and data that are classes-agnostic, use an interface. When you need a certain object type to share characteristics, use an abstract class.✔️
- You should use both an interface and an abstract class when defining any complex object.
Q2. Which statement is true of delegates?
- Delegates are not supported in the current version of C#
- They cannot be used as callbacks.
- Only variables can be passed to delegates as parameters.
- They can be chained together.✔️
Q3. Which choice best defines C#’s asynchronous programming model?
- reactive
- inherited callback
- task-based✔️
- callback-based
Q4. How would you determine if a class has a particular attribute?
var type = typeof(SomeType); var attribute = type.GetCustomAttribute<SomeAttribute>();
var typeof(MyPresentationModel).Should().BeDecoratedWith<SomeAttribute>();
Attribute.GetCustomAttribute, typeof(SubControllerActionToViewDataAttribute)
Attribute.GetCustomAttribute(typeof(ExampleController), typeof(SubControllerActionToViewDataAttribute))✔️
Q5. What is the difference between the ref and out keywords?
- Variables passed to out specify that the parameter is an output parameter, while ref specifies that a variable may be passed to a function without being initialized.
- Variables passed to ref can be passed to a function without being initialized, while out specifies that the value is a reference value that can be changed inside the calling method.
- Variables passed to out can be passed to a function without being initialized, while ref specifies that the value is a reference value that can be changed inside the calling method.✔️
- Variables passed to ref specify that the parameter is an output parameter, while out specifies that a variable may be passed to a function without being initialized.
Q6. How could you retrieve information about a class, as well as create an instance at runtime?
- reflection✔️
- serialization
- abstraction
- dependency injection
Q7. What is this code an example of?
private static object objA;
private static object objB;
private static void performTaskA()
{
lock (objB)
{
Thread.Sleep(1000);
lock (objA) { }
}
}
private static void PerformTaskB()
{
lock (objA)
{
lock (objB) { }
}
}
- a private class that uses multithreading
- multithread coding
- thread mismanagement
- a potential deadlock✔️
Reference Official documentation: Deadlocks and race conditions
Q8. What is the difference between an anonymous type and a regular data type?
- Anonymous types don’t have type names✔️
- Anonymous types can only be static
- Anonymous types can be used only in struts
- Anonymous types don’t work with LINQ.
Reference Official documentation: Anonymous Types
Q9. When would you use a Dictionary rather that an Array type in your application?
- when you need a jagged collection structure
- when you need to store values of the same type
- when you need to store key-value pairs rather than single values✔️
- when you need an ordered, searchable list
Reference Official documentation: Dictionary<TKey,TValue> Class
Q10. What is the difference between a.Equals(b) and a == b?
- The .Equals method compares reference identities while the == compares contents.
- The .Equals method compares primitive values while == compares all values.
- The .Equals method compares contents while == compares references reference identity.✔️
- The .Equals method compares reference type while == compares primitive value types.
Q11. Which choice best describes a deadlock situation?
- when you try to instantiate two objects at the same time in the same class or struct
- when you are trying to execute an action after a user event is registered
- when simultaneous instructions are waiting on each other to finish before executing✔️
- when you try to execute a series of events simultaneously on multiple threads
Reference Official documentation: Deadlocks and race conditions
Q12. How does the async keyword work?
- It allows access to asynchronous methods in the C# API
- It allows thread pooling and synchronous processes in static classes.
- It allows the await keyword to be used in a method✔️
- It allows access to synchronous methods in the C# API
Reference Official documentation: async
Q13. What is an object in C#?
- a class or struct, including its variables and functions
- a primitive data type that can be created only at compile time
- a value type that can be used only with an abstract class
- an instance of a class or struct that includes fields, properties, and/or methods✔️
Reference Official documentation: Objects
Q14. Which code snippet declares an anonymous type named userData?
- var<<!—->T> userData = new <<!—->T> { name = "John", age = 32 };
- var userData = new { name = "John", age = 32 };✔️
- AType userData = new AType { name = "John", age = 32 };
- Anonymous<T> userData = new Anonymous<T> { name = "John", age = 32 };
Reference Official documentation: Anonymous Types
Q15. What will be returned when this method is executed?
public void userInput(string charParamters) { }
- nothing✔️
- a Boolean
- a string variable
- an integer
Reference Official documentation: void
Q16. In what order would the employee names in this example be printed to the console?
string[] employees = { "Joe", "Bob", "Carol", "Alice", "Will" };
IEnumerable<string> employeeQuery = from person in employees
orderby person
select person;
foreach(string employee in employeeQuery)
{
Console.WriteLine(employee);
}
- ascending✔️
- unordered
- descending
- first in, first out
Q17. Lambda expressions are often used in tandem with which of the following?
- Namespaces
- LINQ✔️
- Type Aliasing
- Assemblies
Reference Official documentation: Language Integrated Query (LINQ) Overview
Q18. What is the correct formatting for single line and multiline comments?
- // – Single Line / – Multiline
- // Multiline /_ Single Line _/
- //* Multiline / Single Line
- *// Single Line /_ Multiline _/✔️
Q19. How do you make a method in an abstract class overridable?
- Make it public
- Make it static
- Make it private
- Make it virtual✔️
Reference Official documentation: virtual
Q20. How would you write code for an integer property called Age with a getter and setter?
- public int Age { get – set }
- public int Age: get set;
- public int Age (get, set );
- public int Age { get; set; }✔️
Reference Official documentation: Using Properties
Q21. What is an abstract class?
- a class that is denoted by the class keyword (can be seen and used by any other class in the system–thus it is by default public)
- something denoted by the abstract keyword and used system wide; if you want any program to create an object of a class you use the abstract class
- a class that is denoted by the virtual keyword
- a class that can be used only as base class✔️
Reference Official documentation: Abstract and Sealed Classes and Class Members
Q22. When using a thread pool what happens to a given thread after it finishes its task?
- The thread is destroyed and memory is freed up.
- The thread runs in loop until the next assignment.
- The thread goes inactive in the background and waits for garbage collection.
- The thread returns to the pool for reuse.✔️
Reference Official documentation: ThreadPool Class
Q23. Which choice represents a class that inherits behavior from a base class?
- a second base class
- a revised class
- a derived class✔️
- a parent class
Reference Official documentation: Inheritance
Q24. What does operator overloading allow you to do?
- hide built-in operatores when necessary
- add methods to be interpreted by the compiler at runtime
- define how enums and other primitive value types work within the rest of the application
- define custom functionality for common operators like addition and equality✔️
Reference Official documentation: Operator overloading
Q25. What it the main purpose of LINQ?
- to delete duplicate data
- to bind namespaces and assemblies
- to query and transform data✔️
- to connect assemblies
Reference Official documentation: Language Integrated Query (LINQ) Overview
Q26. What is the correct syntax for a new generic list of strings named contacts?
- public List<string names> contacts = new List<string names>();
- public List(string names) contacts = new List(string names)();
- var contacts = new List<string>();✔️
- var contacts = new List(string);
Reference Official documentation: List<T> Class
Q27. What is the difference between throw exceptions and throw clauses?
- Throw clauses fire only at runtime, while throw exceptions can fire at any time.
- Throw exceptions overwrite the stack trace, while throw clauses retain the stack information.✔️
- Throw clauses overwrite the stack trace, while throw exceptions retain the stack information.
- Throw exceptions fire only at runtime, while throw clauses can fire during compile time.
Reference Official documentation: throw
Q28. When an asynchronous method is executed, the code runs but nothing happens other than a compiler warning. What is most likely causing the method to not return anything?
- The return yield statement is missing at the end of the method.
- The method is missing an await keyword in its body.✔️
- The wait keyword is missing from the end of the method.
- The yield keyword is missing from the method.
Q29. What are C# events?
- system actions that communicate directly with the compiler at runtime
- actions that execute when the code compiles, generating logs and test output
- actions that generate notifications, which are sent to their registered listeners✔️
- user-only methods that send data to the application’s back end
Reference Official documentation: Introduction to events
Q30. What kind of values can arrays store?
- unordered collections of numerc values
- key-value pairs of any C# supported type
- class and struct instances
- multiple variables, or collections, of the same type✔️
Reference Official documentation: Arrays
Q31. Given this enumeration, how would you access the integer-type value of ‘AppState.Loading’?
enum AppState { OffLine, Loading, Ready }
- string currentState = (string)AppState.Loading;
- string currentState = AppState.Loading.integralVal;
- int currentState = AppState.Loading.rawValue;
- int currentState = (int)AppState.Loading;✔️
Reference Official documentation: Enumeration types
Q32. What character would you use to start a regular expression pattern at a word boundary?
- d
- \a
- \b✔️
- \w
Reference Official documentation: Regular Expression Language – Quick Reference
Q33. To conform to the following interface, which of its members need to be implemented?
public interface INameble
{
string FirstName { get; set; }
string LastName { get; }
}
- Both the FirstName and LastName properties need to be implemented.✔️
- Neither, they are both optional.
- Only the LastName property needs to be implemented.
- Only the FirstName property needs to be implemented.
Reference Official documentation: interface
Q34. You’re dealing with multiple assemblies in your program, but are worried about memory allocation. At what point in the program life cycle are assemblies loaded into memory?
- at runtime
- at compile time
- only when required✔️
- only when programmatically loaded
Q35. What is most accurate description of a regular expression?
- A regular expression is a C# tool used to parse HTML
- A regular expression is a special text string for describing a search patters.✔️
- A regular expression allows a variable to be passed by reference.
- A regular expression allows a class to conform to the Equatable protocol.
Q36. Why would you use a class field in C#
- To define behaviours of the class
- To hold information and data contained in the class object✔️
- To communicate between classes and object
- To store the class definition value
Reference Official documentation: Introduction to classes
Q37. When would you use generics in your code?
- to increase code performance
- all of these answers✔️
- when code reuse is a priority
- when type safety is important
Reference Official documentation: Generic classes and methods
Q38. What prints to the console when this code is executed?
public delegate void AuthCallback(bool validUser);
public static AuthCallback loginCallback = Login;
public static void Login()
{
Console.WriteLine("Valid user!");
}
public static void Main(string[] args)
{
loginCallback(true);
}
- Login successful…
- Valid user!
- an error, because the method signature of Login doesn’t match the delegate✔️
- Login successful… Valid user!
Reference Official documentation: Introduction to Delegates
Q39. How would you declare a sealed class named User?
- public class User
- abstract User {}
- sealed class User✔️
- private sealed class User
Reference Official documentation: Abstract and Sealed Classes and Class Members
Q40. What is the correct syntax for a new generic list of strings named contacts? (similar to Q26)
- var contacts = new List<string>();✔️
- var contacts = new List(string);
- public List<string names> contacts = new List<string names>();
- public List(string names) contacts = new List(string names);
Reference Official documentation: List<T>
Q41. What is the difference between non-static and static classes?
- non-static classes need to be initialized before use, while static classes do not✔️
- non-static classes are accessible only from an interface while static classes are accessible from anywhere
- non-static classes need to initialize all class members at runtime, while static classes do not
- non-static classes do not need to be initialized while static classes do
Reference Official documentation: Static Constructors
Q42. Which characteristic prevents this code from compiling?
public int age="28"
- type safety✔️
- single inheritance
- dependency injection
- multiple inheritance
Reference c-sharpcorner: Type Safety in .NET
Q43. How would you serialize this class?
public class User {}
- Mark the User class with the DeserializableAttribute.
- Declare the class as public serializable class User {}.
- Mark the User class with the SerializableAttribute attribute.✔️
- Declare the class as private serializable class User {}.
Reference Official documentation: SerializableAttribute Class
Q44. How would you write a delegate named ResultCallback with an int parameter named responseCode
- public delegate ResultCallback(int responseCode)
- public delegate void ResultCallback<(int) responseCode>;
- public void delegate ResultCallback<int responseCode>;
- public delegate void ResultCallback(int responseCode);✔️
Reference Official documentation: Delegates
Q45. What is the difference between a static and non-static method?
- non-static methods always need to have a void return type
- non-static methods do not have access to static member variables
- static methods do not have to instantiate an instance of the class to call the method✔️
- static methods always have to be public
Reference Official documentation: Static Members
Q46. What is the correct way to write an event named apiResult based on a delegate named ResultCallback?
- public void event ResultCallback apiResult;
- public event ResultCallback(() -> apiResult);
- public event void ResultCallback
- public event ResultCallback apiResult;✔️
Reference Official documentation: Introduction to events
Q47. When will the code inside finally block be executed in a try-catch statement?
- if there is an error, it won’t execute at all
- between the try and catch blocks
- after the try and catch blocks✔️
- when the finally block overrides the catch block and executes in its place
Reference Official documentation: try-catch
Q48. What method correctly extends the string class?
- **public static string IsvalidName(this string i, string value) {}
- public static void IsvalidName(this string i, string value) {}
- public string IsvalidName(this string i, string value) {}
- public void IsvalidName(this string i, string value) {}
Q49. How are C# classses limited?
- They do not support multiple inheritance.✔️
- They support multiple inheritance.
- They can have only a set number of properties.
- They can have only a set number of methods.
Reference Official documentation: Class inheritance
Q50. What function do namespaces perform?
- Namespaces calculate code coverage at runtime.
- Namespaces compile application code together at compile time.
- Namespaces group code together into a single repository.
- Namespaces separate code into groupings, control access, and void naming collisions.✔️
Reference Official documentation: namespace
Q51. What is the correct way to write a public property with a private backing field?
- A
private int _password;
pubic int Password = { get; set; }
- B
private int _password;
public int Password = _password;
- C
private int _password;
public int Password
{
get -> _password;
set-> _password = value;
}
- D ✔️
private int _password;
public int Password
{
get { return _password; }
set { _password = value; }
}
Reference Official documentation: Using Properties
Q52. What is a thread pool?
- a collection of synchronous methods created during initialization that cannot be reused
- a collection of threads created during initialization that can be reused✔️
- a collection of threads only recognized at compile time that can be reused
- a collection of asynchronous methods created at compile time that cannot be reused
Reference Official documentation: ThreadPool Class
Q53. What is the most accurate description of a regular expression?
- A regular expressions allows a variable to be passed by reference
- A regular expression allows a class to conform to the Equatable protocol
- A regular expression is a C# tool used to parse HTML
- A regular expression is a special text string for describing a search pattern✔️
Reference Official documentation: Regular Expression Language – Quick Reference
Q54. When an object in C# is serialized, what is it converted to?
- XML
- JSON
- byte stream✔️
- value stream
Reference: Official documentation: Serialization
Q55. What is a delegate
- a variable that holds a reference to a value type and its content
- a specific value type that can be used only in callback methods
- a type that holds a reference to a method with a particular parameter list and return type✔️
- a custom variable type that can be used in abstract classes
Reference: Official documentation: Delegates
Q56. What are the four keywords associated with exception handling in C#?
- try, catch, valid, invalid
- try, valid, finally, throw
- try, catch, finally, throw✔️
- finally, throw, valid, invalid
Q57. What is the main difference between the is and as operators?
- The is operator checks instance types, while the as operator checks the inherited type.
- The is operator checks primitive data types, while the as operator checks the object type.
- The as operator checks object type, while the is operator attempts to cast an object to a specific type.
- The is operator checks object type, while the as operator attempts to cast an object to a specific type.✔️
Q58. What is the difference between finally and finalize blocks?
- The finally block is called during the execution of a try and catch block, while the finalize method is called after garbage collection.
- The finally block is called after the execution of a try and catch block, while the finalize method is called just before garbage collection.✔️
- The finalize block is called before the execution of a try and catch block, while the finally method is called just before garbage collection.
- The finalize block is called during the execution of a try and catch block, while the finally method is called after garbage collection.
Q59. How would you write an enum variable called AppState with values for Offline, Loading, and Ready?
- enum AppState = [Offline, Loading, Ready]
- enum AppState {"Offline", "Loading", "Ready"}
- enum AppState = {Offline, Loading, Ready}
- enum AppState {Offline, Loading, Ready}✔️
Q60. What is the main difference between a value type and a reference type?
- A value type can be any primitive type, while reference types must be type-agnostic.
- A value type refers to another value, while a reference type refers to a value in memory.
- A value type stores an actual value, while a reference type is a pointer to a value.✔️
- A value type is available only at runtime, while a reference type is available only at compile time.
Q61. What is the difference between the break and continue keywords?
- The break keyword is used to break out of multiple iteration statements, while continue can only break out of code blocks that have single iterations.
- The break keyword literally breaks out of a control flow statement, while continue ignores the rest of the control statement or iteration and starts the next one.✔️
- The break keyword literally breaks out of the current control flow code and stops it dead, while continue keeps executing the code after an exception is thrown.
- The break keyword jumps out of an iteration and then proceeds with the rest of the control flow code, while continue stops the executing code dead.
Official documentation: Jump statements
Q62. Which code snippet correctly declares a variable named userId with a public get and private set?
- public int userID <get, set>;
- public int userID [get, private set];
- public int userID { get; private set; }✔️
- public int userID = { public get, private set };
Official documentation: Properties
Q63. What is true about virtual methods?
- Overriding virtual methods in a derived class is mandatory.
- Overriding virtual methods in a derived class is not possible.
- Virtual methods always need a default implementation.✔️
- Virtual methods cannot have default implementation.
Official documentation: virtual
Q64. What is likely to happen if you have multiple threads accessing the same resource in your program?
- resource overload
- thread jumping
- deadlock and race conditions✔️
- nothing, since this is what threading is for
Official documentation: race conditions
Q65. How do you indicate that a string might be null?
- A string cannot be nullable.
- string? myVariable✔️
- string myVariable = null
- string(null) myVariable
Q66. Do you need to declare an out variable before you use it?
- No, you can declare an out in the parameter list.✔️
- Out variables are no longer part of C#.
- You must declare it if it is a primitive type.
- Yes.
Q67. How would you access the last two people in an array named People?
- People[..^2]
- You cannot do this in C#.
- People[..^3]
- People[^2]
Official Documentation: Ranges
Q68. When can anonymous types be created?
- at compile time✔️
- after runtime
- at runtime
- after compile time
Q69. What is true about thread multitasking?
- Thread multitasking allows code to be executed concurrently✔️
- Thread multitasking allows code to be executed only when handling a user event.
- Thread multitasking blocks code from being executed simultaneously to guard memory.
- Thread multitasking adds single-threaded code blocks together.
Official Documentation: Threads
Q70. What accessibility level does this class field have ?
private string LastName;
- It can be used by other code only in the same class or struct.✔️
- It can be used by other code in a referenced assembly.
- It can be used only by code contained in a derived class.
- It can be used by other code in the same assembly.
Q71. How would you correctly declare a jagged array called ‘partyInvites’ with 10 empty elements?
- string[] partyInvites = new string[10];
- string[][] partyInvites = new string[10][];✔️
- string[][] partyInvites = new string10;
- string <[]> partyInvites = new string <[10]>;
Official Documentation: Jagged Arrays
Q72. How could you pause a thread for three seconds?
- Thread.Pause(3000);
- Thread.Resume(-3000);
- Thread.Suspend(3000);
- Thread.Sleep(3000);✔️
Q73. What is wrong with this code?
void MyFunction()
{
{
int a = 10;
int b = 20;
int c = a + b;
}
Console.WriteLine(c);
}
- Variable c is never used; displaying it on the console does not count as usage.
- Variables a and b are never used.
- You cannot place code inside brackets inside another block.
- Variable c no longer exists outside the block.✔️
Q74. Which statement is True?
- All are true.
- None are true.
- string is a value type.
- string is an alias for String✔️
Q75. Your application has a value type called username that needs to be able to accept null values, but this is generating compile-time errors. How would you fix this in code?
- Null<string> username = null;
- string? username = null;✔️
- Type<string>? username = null;
- Optional<string> username = null;
Q76. Which code snippet correctly declares a custom exception named InvalidResponse?
- struct InvalidResponse: Exception {}
- class InvalidResponse: Exception {}✔️
- public Exception InvalidResponse = new Exception ();
- public Exception InvalidResponse () -> Exception;