Use Select controls to let users select from a pre-defined list of options presented like a text control. Select controls are similar to drop-downs or combo boxes. Users can select one or more options from a set of items with text labels. The Select control has two different modes of operations that developers can choose from: flyout mode and inline mode.
Flyout mode Use flyout mode when you need to conserve on-screen space and when users select only one option at a time. Flyout mode Select controls show only the currently selected item. Users must tap on the control to see other selectable items.
Inline mode Use inline mode when you want the options to be visible all the time or when users can select more than one option at a time. Inline mode Select controls are "always open", which allows several items to be displayed to the user while at rest.