ListBox.SelectionMode Property
Gets or sets the selection behavior for the ListBox control.
Namespace: System.Windows.Controls
Assembly: System.Windows (in System.Windows.dll)
Use the SelectionMode property to specify whether the user can select multiple items and how the user can select the multiple items. Setting SelectionMode to Multiple allows the user to select multiple items with the mouse. Setting SelectionMode to Extended allows the user to select multiple items by pressing a modifier key, such as CTRL or SHIFT.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.