Visual Programming MCQs with Answers
Practice important Visual Programming MCQs with answers and explanations.
Chapter: 33
Q621:
What is the purpose of TaskCompletionSource<T>.SetResult()?
A. It sets the result of the task and completes it
B. It initiates the creation of a new task
C. It marks the task as failed with an exception
D. It starts a new thread to handle the task
Correct Answer:
A
Chapter: 33
Q622:
What will be the output of the following code: Task<int> task = Task.Run(() => { Thread.Sleep(5000); return 42; });?
A. The output will be 42 printed after a delay of 5 seconds
B. The output will be 0 printed immediately
C. The output will be an exception thrown after 5 seconds
D. The output will be 42 printed immediately
Correct Answer:
A
Chapter: 33
Q623:
In the context of threading, what is the main use of the Thread.CurrentThread.IsThreadPoolThread property?
A. To determine if the current thread is a thread pool thread
B. To check if the thread has been created manually
C. To identify if the thread has completed execution
D. To verify if the thread is running in the background
Correct Answer:
A
Chapter: 33
Q624:
What is the effect of calling Task.Wait() on a task that has been completed?
A. It blocks until the task completes, but if already completed, it returns immediately
B. It restarts the task from the beginning
C. It cancels the task if it is already completed
D. It does not affect the task if it is completed
Correct Answer:
A
Chapter: 33
Q625:
How does SynchronizationContext facilitate updating the UI from background threads?
A. It marshals the update requests to the UI thread
B. It creates new UI threads for each update request
C. It prevents the UI thread from being blocked during updates
D. It automatically handles UI thread synchronization for background tasks
Correct Answer:
A
Chapter: 34
Q626:
What is the primary advantage of using asynchronous programming in C#?
A. It allows tasks to run without blocking the main thread and improves responsiveness
B. It automatically manages thread creation and destruction
C. It ensures all tasks are executed in parallel without using any threads
D. It simplifies code by eliminating the need for any form of concurrency
Correct Answer:
A
Chapter: 34
Q627:
How does Task.Run handle CPU-bound tasks compared to I/O-bound tasks?
A. It efficiently handles CPU-bound tasks by using threads from the thread pool
B. It directly handles I/O-bound tasks without creating new threads
C. It avoids thread creation for CPU-bound tasks by using asynchronous operations
D. It cannot be used for CPU-bound tasks and is only suitable for I/O-bound tasks
Correct Answer:
A
Chapter: 34
Q628:
What does the await keyword do in asynchronous programming?
A. It pauses the execution of a method until the awaited task completes
B. It immediately executes the awaited task in a new thread
C. It makes the method synchronous by blocking until the awaited task is completed
D. It executes the awaited task in parallel with other tasks
Correct Answer:
A
Chapter: 34
Q629:
How can the TaskCompletionSource<T> be used in asynchronous programming?
A. It provides a way to manually control the completion of a task, including setting results and handling exceptions
B. It simplifies the creation of tasks by automatically managing their lifecycle
C. It ensures that tasks are completed in a specified order
D. It handles task exceptions and continuations without requiring any additional code
Correct Answer:
A
Chapter: 34
Q630:
In the example provided, what does Task.Run(() => displayprimecounts()); do?
A. It executes the displayprimecounts method asynchronously on a thread pool thread
B. It synchronously calls displayprimecounts on the main thread
C. It delays the execution of displayprimecounts by 5 seconds
D. It starts a new thread for each prime count calculation
Correct Answer:
A
Chapter: 34
Q631:
What is the role of getprimescountasync in the code provided?
A. It asynchronously computes the number of prime numbers in a given range and returns a Task<int>
B. It synchronously computes the number of primes and prints them to the console
C. It starts a new thread to calculate primes and immediately returns the result
D. It waits for the result of prime count computation and handles exceptions
Correct Answer:
A
Chapter: 34
Q632:
How does await differ when used in methods returning Task versus methods returning void?
A. await can be used in both types of methods, but methods returning void are often used for event handlers
B. Methods returning Task require explicit handling of the task's result, while void does not
C. void methods automatically handle continuations, while Task methods need manual continuation handling
D. Methods returning Task allow for chaining continuations and error handling, while void does not
Correct Answer:
A
Chapter: 34
Q633:
What does the Dispatcher.BeginInvoke method do in the context of UI updates?
A. It schedules an action to be executed on the UI thread, allowing UI updates from background threads
B. It creates a new UI thread for each UI update
C. It immediately updates the UI without marshaling
D. It synchronizes UI updates with background threads
Correct Answer:
A
Chapter: 34
Q634:
In the example provided, why is Task.Delay used in the asynchronous method?
A. To introduce a non-blocking delay in the execution flow of the method
B. To block the main thread for a specified duration
C. To pause the execution of the entire application
D. To ensure that tasks complete before continuing execution
Correct Answer:
A
Chapter: 34
Q635:
What does the getprimescount method do in the provided code?
A. It calculates the number of prime numbers within a specified range synchronously
B. It asynchronously computes the prime count and returns the result
C. It creates a new thread to handle prime number calculations
D. It schedules prime number calculations to run at a later time
Correct Answer:
A
Chapter: 34
Q636:
How does the displayprimecounts method differ between synchronous and asynchronous implementations?
A. The asynchronous version uses await to handle tasks without blocking the UI thread, while the synchronous version blocks
B. The synchronous version handles tasks in parallel, while the asynchronous version runs tasks sequentially
C. The asynchronous version executes tasks in the main thread, while the synchronous version uses background threads
D. The synchronous version provides a better user experience due to immediate results, unlike the asynchronous version
Correct Answer:
A
Chapter: 34
Q637:
What does the async keyword indicate in a method definition?
A. The method is asynchronous and can use await to handle tasks
B. The method will execute synchronously regardless of await statements
C. The method will return a Task or Task<T>, but await cannot be used
D. The method is intended for use in event handlers and will not return a result
Correct Answer:
A
Chapter: 34
Q638:
Why is the finally block executed after the await statement in an asynchronous method?
A. To ensure that the finally block runs even if the asynchronous method is interrupted
B. To guarantee that resources are cleaned up before returning from the method
C. To prevent any exceptions from being thrown during the await operation
D. To allow the await statement to complete before executing any additional code
Correct Answer:
B
Chapter: 34
Q639:
What is a key benefit of using async and await in modern C# programming?
A. They simplify asynchronous code by making it easier to read and maintain
B. They automatically optimize performance for CPU-bound tasks
C. They eliminate the need for error handling and exception management
D. They provide parallel processing capabilities for all types of tasks
Correct Answer:
A
Chapter: 34
Q640:
How does Task.Run handle asynchronous operations compared to directly calling a method?
A. It schedules the method to run on a thread pool, which is efficient for asynchronous operations
B. It executes the method synchronously and blocks until completion
C. It creates a new thread for each asynchronous operation, regardless of resource efficiency
D. It immediately executes the method in the main thread
Correct Answer:
A