Xamarin Certification Xamarin.Forms 4

Question 1

Which Xamarin.Forms class is used to create platform-specific code via the Dependency Service pattern?

Accepted Answer

DependencyService

Answer

DependencyService resolves platform-specific implementations of shared interfaces registered with [assembly: Dependency] attributes.

Question 2

What is a Custom Renderer used for in Xamarin.Forms?

Accepted Answer

Overriding the native platform control generated for a Xamarin.Forms element

Answer

Custom Renderers let you subclass the platform renderer to modify or replace the native control that backs a Xamarin.Forms element.

Question 3

Which trigger type in Xamarin.Forms fires when a property on a control changes to a specified value?

Accepted Answer

PropertyTrigger

Answer

PropertyTrigger watches a single BindableProperty and applies setters when the property reaches the specified Value.

Question 4

In Xamarin.Forms, what does the [assembly: ExportRenderer] attribute do?

Accepted Answer

Registers a custom renderer for a specific Xamarin.Forms type in a platform project

Answer

ExportRenderer links a Xamarin.Forms control type to its custom renderer implementation in the platform-specific project.

Question 5

Which Xamarin.Forms animation method animates a view's opacity from its current value to a target value?

Accepted Answer

view.FadeTo

Answer

FadeTo animates the Opacity property of a VisualElement to the specified value over a given duration.

Xamarin Certification Practice Test