Xamarin Certification Xamarin Cross-Platform Architecture

Question 1

What is the Shared Project approach in Xamarin cross-platform development?

Accepted Answer

Source files shared across platform projects at compile time with no output assembly

Answer

A Shared Project contains source files included directly in each referencing platform project at compile time, producing no separate DLL.

Question 2

What is a Portable Class Library (PCL) in Xamarin development?

Accepted Answer

A compiled library targeting a common API subset usable across multiple platforms

Answer

A PCL compiles to a DLL targeting a specific API intersection (profile) supported by the selected platforms.

Question 3

Which .NET project type replaced PCL as the preferred Xamarin shared library format?

Accepted Answer

.NET Standard Library

Answer

.NET Standard Libraries define a versioned API surface supported across all .NET implementations, replacing PCL profiles.

Question 4

In Xamarin cross-platform development, what is the Dependency Service used for?

Accepted Answer

Resolving platform-specific implementations from shared code

Answer

DependencyService allows shared code to call platform-specific implementations registered with [assembly: Dependency] attributes.

Question 5

What design pattern is recommended for separating UI logic from business logic in Xamarin applications?

Accepted Answer

MVVM (Model-View-ViewModel)

Answer

MVVM is the recommended pattern for Xamarin, where ViewModels expose data via bindings and commands, keeping UI logic testable.

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