Question

I have a collection of objects that look like this:

List<MyObject> objects = new List<MyObject>();
objects.Add(new MyObject("Stapler", "Office"));
objects.Add(new MyObject("Pen", "Office"));
objects.Add(new MyObject("Mouse", "Computer"));
objects.Add(new MyObject("Keyboard", "Computer"));
objects.Add(new MyObject("CPU", "Computer"));

class MyObject{

    public string name;
    public string category;

    public MyObject(string n, string c){
    name=n;
    category=c;
    }

}

Can I bind that collection to a List in WPF, and have it display the categories of the objects (without duplicates)? (maybe along with the count of objects that’s in that category)

For example, i would like the list to show only two items, “Office” and “Computer”

Answer 1

Use a CollectionViewSource with a PropertyGroupDescription.

In your Resources, add the following:

<Window.Resources>
    <CollectionViewSource x:Key="MyCollectionViewSource" Source="{Binding Path=CollectionPropertyOnViewModel}">
        <CollectionViewSource.GroupDescriptions>
            <PropertyGroupDescription PropertyName="Category"/>
        </CollectionViewSource.GroupDescriptions>
    </CollectionViewSource>
</Window.Resources>

Then, for your ItemsControl, set the ItemsSource to {Binding Source={StaticResource MyCollectionViewSource}}.

To style the header template, set the ItemsControl.GroupStyle property. Also create a DataTemplate for the items.

Read an excellent blog post from Bea Stollnitz here.