SelectedRows and SelectedCells collection would contain the number of items that correspond to the total number of selected object. However those rows/cells that are not on the current page would be returned as null. To get access to the data key and or original index of a selected row/cell from another page Selection.SelecterRows.GetIDPair(index) or Selection.SelecterCells.GetIDPair(index) should be used.
Requirements
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2