This example demonstrates the virtualization support of the DropDownList. The component has 150 items bound to it; however, when you open the suggestion list, only few items are loaded based on the popup height, and the remaining items are loaded while scrolling.
The DropDownList component supports virtualization, which improves UI performance for large amounts of data. To enable virtualization, set the enableVirtualization property to true. When virtualization is enabled, ComboBox doesn't render the entire suggestion data source on initial component rendering. It loads the N number of items in the popup on initial rendering and the remaining set number of items will load while scrolling. Virtualization works with both local and remote data. To perform the virtualization feature in DropDownList, the VirtualSCroll module have to be injected in the application end.