Listview sort groups (C#, WPF)

Question

I have a list which get dynamically filled. Within the lists the items are grouped. I am trying to sort the groups (not the items within the group) because somehow there are completely mixed up.

I was able to sort the items within the group but didn't find a way to programming sort the groups. Does anyone can give me a hint how to do it or why they are unsorted in the first place?

Init Code:

_lvUsers.ItemsSource = _config.listTestBenches;
CollectionView view = CollectionView)CollectionViewSource.GetDefaultView(_lvUsers.ItemsSource);
PropertyGroupDescription groupDescription = new PropertyGroupDescription("type");
view.GroupDescriptions.Add(groupDescription);

Update GUI:

ICollectionView view = CollectionViewSource.GetDefaultView(_config.listTestBenches);
view.Refresh();

Answer 1

This should help:

<CollectionViewSource Source="{Binding list}" x:Key="cvs">
    <CollectionViewSource.SortDescriptions>
        <!--This will sort groups-->
        <scm:SortDescription PropertyName="type" />
        <!--This will sort items-->
        <scm:SortDescription PropertyName="sortItemName"/>
    </CollectionViewSource.SortDescriptions>
    <CollectionViewSource.GroupDescriptions>
        <dat:PropertyGroupDescription PropertyName="type" />
    </CollectionViewSource.GroupDescriptions>
</CollectionViewSource>

Answer 2

Just att a SortDescription to the same CollectionView :

_lvUsers.ItemsSource = _config.listTestBenches;
CollectionView view = (CollectionView)CollectionViewSource.GetDefaultView(_lvUsers.ItemsSource);
PropertyGroupDescription groupDescription = new PropertyGroupDescription("type");
view.GroupDescriptions.Add(groupDescription);
view.SortDescriptions.Add(new SortDescription("type", ListSortDirection.Ascending));