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How to Display Hierarchical Data

RadPanelBarItem inherits from HeaderedItemsControl therefore it can display hierarchical data, e.g. collections that contain other collections.

The HierarchicalDataTemplate class is designed to be used with HeaderedItemsControl types to display such data. There should be virtually no differences between the usage of HierarchicalDataTemplate in RadPanelBar and other controls.

The following example demonstrates how to create a hierarchical data source and bind a RadPanelBar to it, using a HierarchicalDataTemplate. The ItemsSource property of the HierarchicalDataTemplate specifies the binding that has to be applied to the ItemsSource property of each item. The DataTemplate property specifies the template that has to be applied on each item, while the ItemTemplate is the template applied on its child items.

  1. Create a new class and name it MyViewModel:

        public class MyViewModel
        {
            public MyViewModel()
            {
                this.RelatedItems = new ObservableCollection<object>();
            }
            public string Title { get; set; }
            public DateTime DateCreated { get; set; }
            public double Price { get; set; }
            public IList<object> RelatedItems { get; set; }
        }
    
        Public Class MyViewModel
            Public Sub New()
                Me.RelatedItems = New ObservableCollection(Of Object)()
            End Sub
            Public Property Title() As String
                Get
                    Return _Title
                End Get
                Set(ByVal value As String)
                    _Title = value
                End Set
            End Property
            Private _Title As String
            Public Property DateCreated() As DateTime
                Get
                    Return _DateCreated
                End Get
                Set(ByVal value As DateTime)
                    _DateCreated = value
                End Set
            End Property
            Private _DateCreated As DateTime
            Public Property Price() As Double
                Get
                    Return _Price
                End Get
                Set(ByVal value As Double)
                    _Price = value
                End Set
            End Property
            Private _Price As Double
            Public Property RelatedItems() As IList(Of Object)
                Get
                    Return _RelatedItems
                End Get
                Set(ByVal value As IList(Of Object))
                    _RelatedItems = value
                End Set
            End Property
            Private _RelatedItems As IList(Of Object)
        End Class
    

    The class has four properties:

    • Property Price which is of type double.

    • Property CreatedOn which is of type DateTime.

    • Property Title which is of type string.

    • Property RelatedItems which is a collection of objects. These are the child items. Add a static method to the class which aims to create some mock-up data:

              public static IList<object> GenerateItems()
              {
                  var result = new ObservableCollection<object>();
                  foreach (var num in Enumerable.Range(1, 5))
                  {
                      var item = new MyViewModel();
                      item.DateCreated = DateTime.Today.AddDays(-num % 15);
                      item.Price = num * 100 + Convert.ToDouble(num) / 100;
                      item.Title = String.Format("Item {0}", num);
                      for (int i = 0; i < 5; i++)
                      {
                          var child = new MyViewModel();
                          child.DateCreated = DateTime.Today.AddDays(-num % 5 - i);
                          child.Price = num * 100 + Convert.ToDouble(num + i) / 100;
                          child.Title = String.Format("Item {0}.{1}", num, i);
                          item.RelatedItems.Add(child);
                      }
                      result.Add(item);
                  }
                  return result;
              }
      
              Public Shared Function GenerateItems() As IList(Of Object)
                  Dim result = New ObservableCollection(Of Object)()
                  For Each num In Enumerable.Range(1, 5)
                      Dim item = New MyViewModel()
                      item.DateCreated = DateTime.Today.AddDays(-num Mod 15)
                      item.Price = num * 100 + Convert.ToDouble(num) / 100
                      item.Title = [String].Format("Item {0}", num)
                      For i As Integer = 0 To 4
                          Dim child = New MyViewModel()
                          child.DateCreated = DateTime.Today.AddDays(-num Mod 5 - i)
                          child.Price = num * 100 + Convert.ToDouble(num + i) / 100
                          child.Title = [String].Format("Item {0}.{1}", num, i)
                          item.RelatedItems.Add(child)
                      Next
                      result.Add(item)
                  Next
                  Return result
              End Function
      
  1. Declare a HierarchicalDataTemplate

        <UserControl.Resources>
            <DataTemplate x:Key="PanelBarItemTemplate">
                <StackPanel>
                    <TextBlock Text="{Binding Title}"/>
                    <TextBlock Text="{Binding DateCreated}"/>
                    <TextBlock Text="{Binding Price}"/>
                </StackPanel>
            </DataTemplate>
    
            <HierarchicalDataTemplate x:Key="PanelBarHeaderTemplate"
                                       ItemsSource="{Binding RelatedItems}"
                                       ItemTemplate="{StaticResource PanelBarItemTemplate}">
                <TextBlock Text="{Binding Title}" />
            </HierarchicalDataTemplate>
        </UserControl.Resources>
    
  2. Define the RadPanelBar and set its ItemTemplate property

        <telerik:RadPanelBar x:Name="radPanelBar" Width="200" 
                       HorizontalAlignment="Center" VerticalAlignment="Top"
                       ItemTemplate="{StaticResource PanelBarHeaderTemplate}">
        </telerik:RadPanelBar>
    
  3. Set the ItemsSource property of the RadPanelBar

        this.radPanelBar.ItemsSource = MyViewModel.GenerateItems();
    
    Me.radPanelBar.ItemsSource = MyViewModel.GenerateItems()