Application developers can specify one of these values when constructing a ListView to determine whether the List View will minimize their memory footprint and speed execution by recycling list cells, or will instead generate a cell for every item in the list. Currently, the default behavior is to retain item data in their generated cells when they are not needed. (Items are not needed, for example, when they are far enough off screen that their display is not imminent.) This behavior corresponds to a value of ListViewCachingStrategy.RetainElement. For performance reasons, it is likely that the default behavior will be changed to ListViewCachingStrategy.RecycleElement in a future release. In the meantime, for memory and performance reasons, app developers should specify ListViewCachingStrategy.RecycleElement when constructing a new List View.
The performance advantage of ListViewCachingStrategy.RecycleElement is so great that application developers have been provided with a XAML syntax shortcut for initializing List Views. Instead of x:TypeArguments syntax that specifies a parameter for the ListView.ListView(ListViewCachingStrategy) constructor, XAML for Xamarin.Forms provides a XAML attribute for a non-existent property that corresponds to the caching strategy argument of the constructor. Application developers can set the CachingStrategy attribute to either of the RecycleElement (preferred) or RetainElement values to choose a caching strategy. For example:
<ListView CachingStrategy="RecycleElement" > <ListView.ItemTemplate> <DataTemplate> <ViewCell> <!-- ... --> </ViewCell> </DataTemplate> </ListView.ItemTemplate> </ListView>
|RecycleElement||Indicates that unneeded cells will have their binding contexts updated to that of a cell that is needed.|
|RetainElement||Indicates that for every item in the List View's ItemsView<TVisual>.ItemsSource property, a single unique element will be constructed from the DataTemplate.|
Assembly: Xamarin.Forms.Core (in Xamarin.Forms.Core.dll)
Assembly Versions: 184.108.40.206, 220.127.116.11
The members of Xamarin.Forms.ListViewCachingStrategy are listed below.
See Also: Enum
|RecycleElement||ListViewCachingStrategy. Indicates that unneeded cells will have their binding contexts updated to that of a cell that is needed.|
|RetainElement||ListViewCachingStrategy. Indicates that for every item in the List View's ItemsView<TVisual>.ItemsSource property, a single unique element will be constructed from the DataTemplate.|