how do i create a treeview from an unnested list of objects in code only?

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I'm trying to set up a TreeView in code only from a "flat" list of data objects. I looked at Bea Stollnitz' example, which uses XAML, but I have not been successful in translating it to code-only. I have:

C#

ObservableCollection<animalobject> myAnimals = new ObservableCollection<animalobject>();
myAnimals.Add(new AnimalObject("mammal","cat"));
myAnimals.Add(new AnimalObject("mammal","dog"));
myAnimals.Add(new AnimalObject("bird","canary"));
myAnimals.Add(new AnimalObject("bird","eagle"));
myAnimals.Add(new AnimalObject("reptile","snake"));
myAnimals.Add(new AnimalObject("reptile","lizard"));
myAnimals.Add(new AnimalObject("reptile","dragon"));

ListCollectionView view = CollectionViewSource.GetDefaultView(myAnimals) as ListCollectionView;
view.GroupDescriptions.Add(new PropertyGroupDescription("Category"));
view.SortDescriptions.Add(new SortDescription("Category", ListSortDirection.Ascending));
view.SortDescriptions.Add(new SortDescription("AnimalName", ListSortDirection.Descending));
</animalobject></animalobject>

I can't figure out how to set up the HierarchicalDataTemplate. I want the tree to display categories expanding to display the animals belonging to each.

Thanks!

Posted 17-Jun-11 11:19am

devi42

Updated 18-Jun-11 6:10am

Kim Togo

v2

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Mark Salsbery · Answer 1 · 2011-06-18T10:14:00

Something like this maybe...

StringReader stringReader = new StringReader("<ResourceDictionary xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" > <DataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" xmlns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\" x:Key=\"animalTemplate\"> <TextBlock Text=\"{Binding Path=AnimalName}\"/> </DataTemplate> <HierarchicalDataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" xmlns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\" x:Key=\"categoryTemplate\" ItemsSource=\"{Binding Path=Items}\" ItemTemplate=\"{StaticResource animalTemplate}\"> <TextBlock Text=\"{Binding Path=Name}\" FontWeight=\"Bold\" /> </HierarchicalDataTemplate> </ResourceDictionary>");
XmlReader xmlReader = XmlReader.Create(stringReader);
this.Resources = (ResourceDictionary)XamlReader.Load(xmlReader);

treeView1.ItemTemplate = (DataTemplate)this.FindResource("categoryTemplate");

ObservableCollection<AnimalObject> myAnimals = new ObservableCollection<AnimalObject>();
myAnimals.Add(new AnimalObject("mammal", "cat"));
myAnimals.Add(new AnimalObject("mammal", "dog"));
myAnimals.Add(new AnimalObject("bird", "canary"));
myAnimals.Add(new AnimalObject("bird", "eagle"));
myAnimals.Add(new AnimalObject("reptile", "snake"));
myAnimals.Add(new AnimalObject("reptile", "lizard"));
myAnimals.Add(new AnimalObject("reptile", "dragon"));

ListCollectionView view = CollectionViewSource.GetDefaultView(myAnimals) as ListCollectionView;
view.GroupDescriptions.Add(new PropertyGroupDescription("Category"));
view.SortDescriptions.Add(new SortDescription("Category", ListSortDirection.Ascending));
view.SortDescriptions.Add(new SortDescription("AnimalName", ListSortDirection.Descending));

Binding binding = new Binding("Groups");
binding.Source = view;
treeView1.SetBinding(TreeView.ItemsSourceProperty, binding);