// declarations from commctrl.h
type
  TLVGROUP = record
  cbSize: UINT;
  mask: UINT;
  pszHeader: LPWSTR;
  cchHeader: Integer;
  pszFooter: LPWSTR;
  cchFooter: Integer;
  iGroupIdL: Integer;
  stateMask: UINT;
  state: UINT;
  uAlign: UINT;
  end;
  tagLVITEMA = packed record
  mask: UINT;
  iItem: Integer;
  iSubItem: Integer;
  state: UINT;
  stateMask: UINT;
  pszText: PAnsiChar;
  cchTextMax: Integer;
  iImage: Integer;
  lParam: lParam;
  iIndent: Integer;
  iGroupId: Integer;
  cColumns: UINT;
  puColumns: PUINT;
  end;
  TLVITEMA = tagLVITEMA;
 const
  LVM_ENABLEGROUPVIEW = LVM_FIRST + 157;
  LVM_MOVEITEMTOGROUP = LVM_FIRST + 154;
  LVM_INSERTGROUP = LVM_FIRST + 145;
  LVIF_GROUPID = $0100;
  LVGF_HEADER = $00000001;
  LVGF_ALIGN = $00000008;
  LVGF_GROUPID = $00000010;
  LVGA_HEADER_LEFT = $00000001;
  LVGA_HEADER_CENTER = $00000002;
  LVGA_HEADER_RIGHT = $00000004;

 procedure TForm1.Button1Click(Sender: TObject);
 var
  LvGroup: TLVGROUP;
  LvItemA: TLVITEMA;
  ListItem: TListItem;
  I: Byte;
 begin
  // Fill listview with random data
 Randomize;
  for i := 1 to 10 do
  begin
  ListItem := ListView1.Items.Add;
  ListItem.Caption := IntToStr(Random(100));
  end;
  SendMessage(ListView1.Handle, LVM_ENABLEGROUPVIEW, 1, 0);
  // Create Group1
 FillChar(LvGroup, SizeOf(TLVGROUP), 0);
  with LvGroup do
  begin
  cbSize := SizeOf(TLVGROUP);
  mask := LVGF_HEADER or LVGF_ALIGN or LVGF_GROUPID;
  pszHeader := 'Group 1';
  cchHeader := Length(LvGroup.pszHeader);
  iGroupIdL := 0;
  uAlign := LVGA_HEADER_CENTER;
  end;
  SendMessage(ListView1.Handle, LVM_INSERTGROUP, 0, Longint(@LvGroup));
  // Create Group2
 FillChar(LvGroup, SizeOf(LvGroup), 0);
  with LvGroup do
  begin
  cbSize := SizeOf(TLVGROUP);
  mask := LVGF_HEADER or LVGF_ALIGN or LVGF_GROUPID;
  pszHeader := 'Group 2';
  cchHeader := Length(LvGroup.pszHeader);
  iGroupIdL := 1;
  uAlign := LVGA_HEADER_LEFT
  end;
  SendMessage(ListView1.Handle, LVM_INSERTGROUP, 1, Longint(@LvGroup));
  // Assign items to the groups
 for I := 0 to ListView1.Items.Count - 1 do
  begin
  with LvItemA do
  begin
  FillChar(LvItemA, SizeOf(TLvItemA), 0);
  mask := LVIF_GROUPID;
  iItem := I;
  iGroupId := Random(2);
  end;
  SendMessage(ListView1.Handle, LVM_SETITEM, 0, Longint(@LvItemA))
  end;
 end;

 // XPManifest needed!