How to: Group Items in a Windows Forms ListView Control
With the grouping feature of the ListView control, you can display related sets of items in groups. These groups are separated on the screen by horizontal group headers that contain the group titles. You can use ListView groups to make navigating large lists easier by grouping items alphabetically, by date, or by any other logical grouping. The following image shows some grouped items.
ListView grouped items
To enable grouping, you must first create one or more groups either in the designer or programmatically. After a group has been defined, you can assign ListView items to groups. You can also move items from one group to another programmatically.
ListView groups are available only on Windows XP Home Edition, Windows XP Professional, Windows Server 2003 when your application calls the Application.EnableVisualStyles method. On earlier operating systems, any code relating to groups has no effect and the groups will not appear. For more information, see ListView.Groups.
Removing a group does not remove the items within that group.
Set the ListViewItem.Group property of individual items.