Xamarin Certification Xamarin Data and Services 3

Question 1

What is the purpose of the Polly library in Xamarin HTTP communication?

Accepted Answer

Provides resilience policies like retry, circuit breaker, and timeout for HTTP calls

Answer

Polly is a .NET resilience library that allows defining policies (retry, circuit breaker, fallback) applied to any code, including HttpClient calls.

Question 2

In Xamarin SQLite-Net, which attribute marks a property as the primary key with auto-increment?

Accepted Answer

[PrimaryKey, AutoIncrement]

Answer

Combining [PrimaryKey] and [AutoIncrement] attributes on an integer property configures SQLite to auto-generate unique IDs.

Question 3

Which method is used to create or open a SQLite database asynchronously using SQLite-Net in Xamarin?

Accepted Answer

new SQLiteAsyncConnection(path)

Answer

SQLiteAsyncConnection is constructed with the database file path and provides async methods for CRUD operations without blocking the UI thread.

Question 4

In Xamarin, what is the purpose of the Circuit Breaker pattern in service communication?

Accepted Answer

Stops sending requests to a failing service temporarily to allow recovery

Answer

The Circuit Breaker pattern monitors failures and opens the circuit (stops requests) after a threshold, preventing cascading failures while the service recovers.

Question 5

Which Xamarin.Essentials method sends an email using the device's default mail app?

Accepted Answer

Email.ComposeAsync

Answer

Xamarin.Essentials Email.ComposeAsync opens the platform's native mail app pre-filled with the provided subject, body, and recipients.

Xamarin Certification Practice Test

Xamarin Certification Practice Test

Xamarin Certification Xamarin Data and Services 3