Enables or disables whether the items in a list view control display as a group.
Indicates whether to enable a listview control to group displayed items. TRUE to enable grouping; FALSE to disable it.
Returns one of the following values:
0 The ability to display list view items as a group is already enabled or disabled.
1 The state of the control was successfully changed.
-1 The operation failed.
This member function emulates the functionality of the LVM_ENABLEGROUPVIEW message, as described in the Windows SDK.