A lot still broken, in particular virtualization is completely removed.`ItemsPresenter` now no longer has an `Items` or `ItemTemplate` property; it detects when it's hosted in an `ItemsControl`. `IItemsPresenter` interface removed.
- Removes the `IStyler` service and the `Styler` implementation
- Moves the logic for applying styles and control themes into `StyledElement`
- Removes the style `TryAttach` method from the public API
- Removes style caching for now - this will need to be added back
In #4218 we imported `IElementFactory` from WinUI which is broadly analogous to a recycling datatemplate for lists. In Avalonia this implement `IDataTemplate` in order to have a common base class for all types of data templates.
The problem with this is that `IDataTemplate` already had a `SupportsRecycling` property which is incompatible with the way recycling is implemented in `IElementFactory`. Instead, introduce an `IRecyclingDataTemplate` to signal data templates that support recycling.
And remove child selection when a `TreeViewItem` is un-expanded.
This is necessary because we don't get enough information about a materialized `TreeViewItem` to select it when materialized, so the `SelectionModel` and `TreeViewItem` selection state gets out of sync.
Update `TreeItemContainerGenerator.Index` when a `TreeViewItem` is added to or removed from the logical tree. This ensures that removed `TreeViewItem`s won't try to add duplicate containers to the index.
Fixes#2985
Simon Cropp
Emmanuel Hansen
Max Katz
Steven Kirk
Glen Nicol
Giuseppe Lippolis
Takoooooo
gabornemeth
Dan Walmsley
Nikita Tsukanov
Michael Bosschert
MonkAlex
Dariusz Komosinski