public void DisableGroups() {
if (!this.IsGroupsEnabled) return;
this.Groups.Clear();
this._IIListView.RemoveAllGroups();
this._IIListView.EnableGroupView(0);
this._IIListView.SetOwnerDataCallback(IntPtr.Zero);
this.LastGroupCollumn = null;
this.LastGroupOrder = SortOrder.None;
this.IsGroupsEnabled = false;
}