#include <GUIConstantsEx.au3>
#include <GuiImageList.au3>
#include <GuiListView.au3>
#include <MsgBoxConstants.au3>

Example()

Func Example()
        GUICreate("ListView Remove All Groups (v" & @AutoItVersion & ")", 400, 300)
        Local $idListview = GUICtrlCreateListView("", 2, 2, 394, 268)
        ; Enable extended control styles
        _GUICtrlListView_SetExtendedListViewStyle($idListview, BitOR($LVS_EX_FULLROWSELECT, $LVS_EX_SUBITEMIMAGES))
        GUISetState(@SW_SHOW)

        ; Load images
        Local $hImage = _GUIImageList_Create()
        _GUIImageList_Add($hImage, _GUICtrlListView_CreateSolidBitMap($idListview, 0xFF0000, 16, 16))
        _GUIImageList_Add($hImage, _GUICtrlListView_CreateSolidBitMap($idListview, 0x00FF00, 16, 16))
        _GUIImageList_Add($hImage, _GUICtrlListView_CreateSolidBitMap($idListview, 0x0000FF, 16, 16))
        _GUICtrlListView_SetImageList($idListview, $hImage, 1)

        ; Add columns
        _GUICtrlListView_AddColumn($idListview, "Column 1", 100)
        _GUICtrlListView_AddColumn($idListview, "Column 2", 100)
        _GUICtrlListView_AddColumn($idListview, "Column 3", 100)

        ; Add items
        _GUICtrlListView_AddItem($idListview, "Row 1: Col 1", 0)
        _GUICtrlListView_AddSubItem($idListview, 0, "Row 1: Col 2", 1, 1)
        _GUICtrlListView_AddSubItem($idListview, 0, "Row 1: Col 3", 2, 2)
        _GUICtrlListView_AddItem($idListview, "Row 2: Col 1", 1)
        _GUICtrlListView_AddSubItem($idListview, 1, "Row 2: Col 2", 1, 2)
        _GUICtrlListView_AddItem($idListview, "Row 3: Col 1", 2)

        ; Build groups
        _GUICtrlListView_EnableGroupView($idListview)
        _GUICtrlListView_InsertGroup($idListview, -1, 1, "Group 1")
        _GUICtrlListView_InsertGroup($idListview, -1, 2, "Group 2")
        _GUICtrlListView_SetItemGroupID($idListview, 0, 1)
        _GUICtrlListView_SetItemGroupID($idListview, 1, 2)
        _GUICtrlListView_SetItemGroupID($idListview, 2, 2)

        ; Remove all groups
        MsgBox($MB_SYSTEMMODAL, "Information", "Removing groups")
        _GUICtrlListView_RemoveAllGroups($idListview)

        ; Loop until the user exits.
        Do
        Until GUIGetMsg() = $GUI_EVENT_CLOSE
        GUIDelete()
EndFunc   ;==>Example