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How to load items in WPF HierarchyNavigator (Breadcrumb) control in on-demand?
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This article describes how to dynamically load next level items (on-demand loading) in WPF HierarchyNavigator (Breadcrumb) when item is selected.
In this example, files in the system drive are load as next level items in on-demand using the HierarchyNavigatorSelectedItemChanged event.
The following code example demonstrates the same.
XAML
MainWindow.xaml
<Grid>
<syncfusion:HierarchyNavigator ItemsSource = "{Binding HierarchyItems}" x:Name="hierarchy" Height="50" Width="500" HierarchyNavigatorSelectedItemChanged="Hierarchy_HierarchyNavigatorSelectedItemChanged">
<syncfusion:HierarchyNavigator.ItemTemplate>
<HierarchicalDataTemplate ItemsSource = "{Binding FileItems}" >
<TextBlock Text="{Binding Content}"/>
</HierarchicalDataTemplate>
</syncfusion:HierarchyNavigator.ItemTemplate>
</syncfusion:HierarchyNavigator>
</Grid>
In the below code, next level items are added to the collection in HierarchyNavigatorSelectedItemChanged in on-demand.
C#
MainWindow.xaml.cs
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void Hierarchy_HierarchyNavigatorSelectedItemChanged(object sender, Syncfusion.Windows.Tools.Controls.HierarchyNavigatorSelectedItemChangedEventArgs e)
{
if (hierarchy.SelectedItem == null)
return;
HierarchicalModel selectedItem = hierarchy.SelectedItem as HierarchicalModel;
string[] dirs = Directory.GetDirectories(selectedItem.Content, "*", SearchOption.TopDirectoryOnly);
foreach (string dir in dirs)
{
selectedItem.FileItems.Add(new HierarchicalModel(dir));
}
}
}
HierarchicalModel.cs
public class HierarchicalModel
{
public HierarchicalModel(string content, params HierarchicalModel[] items)
{
Content = content;
fileItems = new ObservableCollection<HierarchicalModel>();
foreach (var item in items)
{
fileItems.Add(item);
}
}
private ObservableCollection<HierarchicalModel> fileItems;
public ObservableCollection<HierarchicalModel> FileItems
{
get { return fileItems; }
set
{
if (fileItems != value)
{
fileItems = value;
}
}
}
public string Content { get; set; }
}
HierarchicalViewModel.cs
public class HierarchicalViewModel
{
public HierarchicalViewModel()
{
hierarchyItems = new ObservableCollection<HierarchicalModel>();
this.hierarchyItems.Add(
new HierarchicalModel("My Files",
new HierarchicalModel("D:\\"),
new HierarchicalModel("C:\\"))
);
}
private ObservableCollection<HierarchicalModel> hierarchyItems;
public ObservableCollection<HierarchicalModel> HierarchyItems
{
get { return hierarchyItems; }
set { hierarchyItems = value; }
}
}
The output for the above code is shown below:
