Use the GroupItemCount property to specify the number of items to be grouped together in the ListView control. (In other words, this specifies the number of items to display for each group of the control.) For each group, the ListView control renders the contents of the GroupTemplate template and replaces the item placeholder with the actual item content. It does this as many times as the number of items defined by the GroupItemCount property.
You can use GroupItemCount with the GroupTemplate template to create a tiled layout in the ListView control. In a tiled table layout, the items are repeated horizontally in a row. The numbers of times that an item is repeated is specified by the GroupItemCount property.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)