Prism.Forms.LazyView

Lazy load Xamarin Forms views with Prism

Directly inspired by @andreinitescu work discribed here https://enginecore.blogspot.com/2019/01/xamarin-forms-lazy-load-tabs-in_10.html. The original code has been adapted to Prism and published on Nuget.

How to use it?

Install the Prism.Forms.LazyView nuget package:

Then for example on a TabbedPage:

• Add some references:

  xmlns:views="clr-namespace:YOUR.PROJECT.VIEWS.NAMESPACE;assembly=YOUR.PROJECT.ASSEMBLY"
  xmlns:lazyView="clr-namespace:Prism.Forms.LazyView;assembly=Prism.Forms.LazyView"
  

• Add some lazy tabs like this one:

  <lazyView:LazyContentPage Title="YOUR TAB NAME" x:TypeArguments="views:YOUR_CONTENT_VIEW"/>
  

• or with background thread loading

  <lazyView:LazyContentPage Title="YOUR TAB NAME" x:TypeArguments="views:YOUR_LOADING_VIEW,views:YOUR_CONTENT_VIEW"/>
  

• Register your lazy page for navigartion

  containerRegistry.RegisterForNavigation<LazyContentPage<YOUR_CONTENT_VIEW>, YOUR_CONTENT_VIEWMODEL>(nameof(YOUR_CONTENT_VIEW));
  

• or with background thread loading

  containerRegistry.RegisterForNavigation<LazyContentPage<YOUR_LOADING_VIEW,YOUR_CONTENT_VIEW>, YOUR_CONTENT_VIEWMODEL>(nameof(YOUR_CONTENT_VIEW));
  

YOUR_CONTENT_VIEW should be a Xamarin.Forms ContentView and will be created once tab clicked

YOUR_LOADING_VIEW should be a Xamarin.Forms ContentView and will be displayed while lazy loading YOUR_CONTENT_VIEW in a background thread

Actually, it should work with any Prism control implementing MultiPageActiveAwareBehavior (e.g. Tabbed and Carousel), but you can make it work from anywhere you're able to toggle the IsActive property (see "EncrustedSlowContentView").

Now toggling IsActive on view side call OnAppearing/OnDisappearing on viewmodel side.

More details on Sample project