private void OnGroupRemoved(FilterGroupViewModel group)
{
_filterGroups.Remove(group);
group.Removed -= OnGroupRemoved;
group.PropertyChanged -= GroupOnPropertyChanged;
UpdateFilterExpression();
}
private void AddGroup()
{
var group = new FilterGroupViewModel();
_filterGroups.Add(group);
group.Removed += OnGroupRemoved;
group.PropertyChanged += GroupOnPropertyChanged;
UpdateFilterExpression();
}