Unselects any selected rows/cards within a View.
Multiple row/card selection isn't allowed if the DataViewBase.NavigationStyle property is set to GridViewNavigationStyle.None and the TableView.MultiSelectMode (CardView.MultiSelectMode in card views) property is set to 'None'.
The UnselectAll method clears the current selection (clears the DataControlBase.SelectedItems collection). To select all rows/cards, use the DataControlBase.SelectAll method. To select or unselect individual rows/cards, use the DataControlBase.SelectItem and DataControlBase.UnselectItem methods, respectively.
To learn more, see Multiple Row Selection.