Question

I am trying to use link to group data and use it directly in treeview1.itemsource. The
code I used is:

DisksTreeView1.ItemsSource = (From g As Classes.DiskPrime In CurrentVariables.DisksList
                                     Group By g.Genre
                                      Into MyGroup = Group)

and Xaml is:

<TreeView Name="DisksTreeView1" >
    <TreeView.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Namee}" />
        </DataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

The class code is:

Public Class DiskPrime
        Property ID As String
        Property Namee As String
        Property Genre As String
        Property DateCreated As Date
        Property Path As String   
End Class

After running the program I am only getting a blank treeview, could you please correct me where i have done wrong. Thank you.

Answer 1

Using GroupBy returns an IEnumerable<IGrouping<string, DiskPrime>>, which means you are actually binding to an IGrouping<string, DiskPrime> and not to a DiskPrime.

To see the group names you could bind to Key rather than Namee

This will only display the first level though (the group names). In order to see which elements each group contains, you’ll need to use HierarchicalDataTemplate instead of DataTemplate.