ItemContainerGenerator Class

Namespace: Avalonia.Controls.Generators
Assembly: Avalonia.Controls (in Avalonia.Controls.dll) Version: 11.3.999

Inheritance

Object    ItemContainerGenerator

Derived

Avalonia.Controls.GeneratorsTreeItemContainerGenerator

When creating a container for an item from a VirtualizingPanel, the following process should be followed: - NeedsContainer(Object, Int32, Object) should first be called to determine whether the item needs a container. This method will return true if the item should be wrapped in a container control, or false if the item itself can be used as a container. - If NeedsContainer(Object, Int32, Object) returns true then the CreateContainer(Object, Int32, Object) method should be called to create a new container, passing the recycle key returned from NeedsContainer(Object, Int32, Object). - If the panel supports recycling and the recycle key is non-null then the recycle key should be recorded for the container (e.g. in an attached property or the realized container list). - PrepareItemContainer(Control, Object, Int32) method should be called for the container. - The container should then be added to the panel using AddInternalChild(Control) - Finally, ItemContainerPrepared(Control, Object, Int32) should be called. NOTE: If NeedsContainer(Object, Int32, Object) in the first step above returns false then the above steps should be carried out a single time: the first time the item is displayed. Otherwise the steps should be carried out each time a new container is realized for an item. When unrealizing a container, the following process should be followed: - If NeedsContainer(Object, Int32, Object) for the item returned false then the item cannot be unrealized or recycled. - Otherwise, ClearItemContainer(Control) should be called for the container - If recycling is supported by the panel and the container then the container should be added to a recycle pool keyed on the recycle key returned from NeedsContainer(Object, Int32, Object). It is assumed that recycled containers will not be removed from the panel but instead hidden from view using e.g. `container.IsVisible = false`. - If recycling is not supported then the container should be removed from the panel. When recycling an unrealized container, the following process should be followed: - NeedsContainer(Object, Int32, Object) should be called to determine whether the item needs a container, and if so, the recycle key. - A container should be taken from the recycle pool keyed on the returned recycle key. - The container should be made visible. - PrepareItemContainer(Control, Object, Int32) method should be called for the container. - ItemContainerPrepared(Control, Object, Int32) should be called. NOTE: Although this class is similar to that found in WPF/UWP, in Avalonia this class only concerns itself with generating and clearing item containers; it does not maintain a record of the currently realized containers, that responsibility is delegated to the items panel.