Task and Task of T types in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Task in C#?

A Task represents an asynchronous operation that does not return a value. It lets your program do work in the background without blocking the main thread.

beginner

What is the difference between Task and Task<T>?

Task is for async operations that return no result. Task<T> is for async operations that return a value of type T when completed.

beginner

How do you get the result from a Task<T>?

You can use the await keyword to wait for the task to finish and get its result, like: T result = await task;

intermediate

What happens if you call Wait() on a Task?

Calling Wait() blocks the current thread until the task finishes. This can cause your program to freeze if used on the main thread.

intermediate

Why is using async and await better than blocking with Wait()?

Because <code>async</code> and <code>await</code> let your program continue running other work while waiting, improving responsiveness and avoiding freezes.

Which type should you use for an async method that returns a number?

A void

B Task

C Task<int>

D int

Use Task<int> to represent an async operation that returns an integer.

What does await do when used with a Task?

A Blocks the thread until the task finishes

B Pauses the method until the task completes without blocking the thread

C Starts the task

D Cancels the task

await pauses the method but lets other work run on the thread.

What is the return type of an async method that does not return a value?

A Task

B Task<void>

C void

D int

Async methods that don't return a value should return Task.

Which of these can cause your UI to freeze?

A Calling <code>Wait()</code> on a Task on the UI thread

B Using <code>await</code> on a Task

C Returning <code>Task&lt;T&gt;</code> from a method

D Using <code>async</code> keyword

Calling Wait() blocks the thread and can freeze the UI.

How do you declare an async method that returns a string?

A string MethodName()

B async void MethodName()

C Task MethodName()

D async Task<string> MethodName()

Use async Task<string> to return a string asynchronously.

Explain the difference between Task and Task<T> and when to use each.

Think about whether your async method returns a value or not.

Describe how await works with Task and why it is preferred over blocking calls.

Consider what happens to the program flow when you await a task.