What is UI Virtualization?
UI Virtualization is a concept where UI Elements are only created and maintained when they are visible on the screen. UI Virtualization is particularly meaningful when displaying a large list of items, such as the content of a database. For example, consider a 50,000-entry database: populating a ListBox with 50,000 UI Elements would have extremely low performance. Instead, by virtualizing all elements that are not visible (scrolled outside of view), only a small subset of the 50,000 entries needs to be created and maintained. The concept of UI Virtualization in WPF is currently only implemented in the ItemsControl base class. To accomplish proper UI Virtualization, the ItemsControl class relies on the ItemContainerGenerator interface/class. When used in conjunction with a virtualizing Panel, the ItemContainerGenerator allows UI elements to be created and destroyed as they are required.
