Changes

** This is especially an issue in Xamarin, both for performance, but also because sfListViewExt tends to cause layouting issues by taking up more space than needed, unlike in UWP where a ListViewExt is capable of calculating its size based on the size of its items. Therefore, when using nested ListViews in Xamarin, constrain the size of the inner ListView with a fixed HeightRequest attribute (or WidthRequest in the case of a horizontal list).

** 🏆 '''Alternatives to the optimized ListViews should be used with extreme caution.''' Controls such as CollectionView or BindableLayout are not optimized for good performance in UBIK.

** Sometimes it’s unavoidable that multiple containers are needed. In Xamarin, applying the [[Xamarin_XAML#Layout_compression_examples|HeadlessLayout]] style can reduce their impact on the visual tree.

** Some ideas for reducing the number of nested controls can be seen [[XAML_Best_practices#Alternatives_to_using_Multiple_Controls|later in this article]].

* The localized Style definitions in this StackPanel will be passed down to all controls contained within it, no matter how deep the nesting goes.

* The BasedOn attribute can be used to create a sub-style based on another existing style. However, the TargetType must always match.

=== Simplifying Layouts ===

In UWP / on desktop UBIK, the processor is generally powerful enough to handle more complex UIs. However, mobile devices running Xamarin versions of UBIK will noticeably struggle to render sophisticated UIs made of deeply nested levels of containers. There are two ways this situation can be improved; the first is to reduce the number of containers used, and the second is to apply [[Xamarin_XAML#Layout_compression_examples|Layout Compression]] wherever possible. Finally, some ideas will be presented for other ways to reduce the number of controls needed to render the same UI.

==== Reducing Containers ====

Another thing to consider is how many times this particular UI definition will be rendered on screen. You have more freedom to be uneconomical in your use of controls when when designing items that will appear once on a page, such as the page header, rather than with item templates or control templates that are rendered several, or even dozens, of times in one view.

==== Alternatives to using Multiple Controls ====

[[Category:Pages with broken file links|XAML Best practices]]