IsExpandedBinding and IsExpandableBinding

Since Q1 2013 release, RadTreeListView has two new properties - IsExpandedBinding and IsExpandableBinding which can be used to synchronize its expanded and expandable states with your view-model.

Binding to the IsExpanded property of TreeListViewRow is not fully supported. You can consider using IsExpandedBinding property instead.

Use of IsExpandedBinding

IsExpandedBinding property can be used to show you whether a TreeListView's row is expanded or not.

Follow these steps to accomplish the task:

1. For the purpose of this tutorial we will add a boolean property - IsExpanded to our WarehouseItem collection:

   Please, note that our WarehouseItem class implements the INotifyPropertyChanged interface.

       public class WarehouseItem : INotifyPropertyChanged 
       { 
           public event PropertyChangedEventHandler PropertyChanged; 
    
           private bool isExpanded; 
           private string name; 
           private int count; 
    
           public WarehouseItem(string name, int count, bool isExpanded = true) 
           { 
               this.Name = name; 
               this.IsExpanded = isExpanded;            
           } 
    
           public string Name 
           { 
               get 
               { 
                   return this.name; 
               } 
               set 
               { 
                   if (value != this.name) 
                   { 
                       this.name = value; 
                       this.OnPropertyChanged("Name"); 
                   } 
               } 
           } 
    
           public bool IsExpanded 
           { 
               get 
               { 
                   return this.isExpanded; 
               } 
               set 
               { 
                   if (value != this.isExpanded) 
                   { 
                       this.isExpanded = value; 
                       this.OnPropertyChanged("IsExpanded"); 
                   } 
               } 
           } 
       protected virtual void OnPropertyChanged(PropertyChangedEventArgs args) 
           { 
               PropertyChangedEventHandler handler = this.PropertyChanged; 
               if (handler != null) 
               { 
                   handler(this, args); 
               } 
           } 
    
           private void OnPropertyChanged(string propertyName) 
           { 
               this.OnPropertyChanged(new PropertyChangedEventArgs(propertyName)); 
           } 
   

       Public Class WarehouseItem 
           Implements INotifyPropertyChanged 
           Public Event PropertyChanged As PropertyChangedEventHandler 
    
           Private m_isExpanded As Boolean 
           Private m_name As String 
           Private count As Integer 
    
           Public Sub New(name As String, count As Integer, Optional isExpanded As Boolean = True) 
               Me.Name = name 
               Me.IsExpanded = isExpanded 
           End Sub 
    
           Public Property Name() As String 
               Get 
                   Return Me.m_name 
               End Get 
               Set(value As String) 
                   If value <> Me.m_name Then 
                       Me.m_name = value 
                       Me.OnPropertyChanged("Name") 
                   End If 
               End Set 
           End Property 
    
           Public Property IsExpanded() As Boolean 
               Get 
                   Return Me.m_isExpanded 
               End Get 
               Set(value As Boolean) 
                   If value <> Me.m_isExpanded Then 
                       Me.m_isExpanded = value 
                       Me.OnPropertyChanged("IsExpanded") 
                   End If 
               End Set 
           End Property 
           Protected Overridable Sub OnPropertyChanged(args As PropertyChangedEventArgs) 
               Dim handler As PropertyChangedEventHandler = Me.PropertyChanged 
               RaiseEvent handler(Me, args) 
           End Sub 
    
           Private Sub OnPropertyChanged(propertyName As String) 
               Me.OnPropertyChanged(New PropertyChangedEventArgs(propertyName)) 
           End Sub 
       End Class 
   

2. Add RadTreeListView as demonstrated below:

       <telerik:RadTreeListView x:Name="radTreeListView" 
                                    IsExpandedBinding="{Binding IsExpanded, Mode=TwoWay}" 
                                    AutoGenerateColumns="False"> 
               <telerik:RadTreeListView.ChildTableDefinitions> 
                   <telerik:TreeListViewTableDefinition ItemsSource="{Binding Items}" /> 
               </telerik:RadTreeListView.ChildTableDefinitions> 
               <telerik:RadTreeListView.Columns> 
                   <telerik:GridViewDataColumn DataMemberBinding="{Binding Name}" 
                                       Header="Name" /> 
                   <telerik:GridViewDataColumn DataMemberBinding="{Binding IsExpanded}"  
                                       Header="Is Expanded" /> 
               </telerik:RadTreeListView.Columns> 
           </telerik:RadTreeListView> 
   

3. Here is a snapshot of the result:

A complete example of using RadTreeListView's IsExpandedBinding property is available in the TreeListView's IsExpanded demo.

Use of IsExpandableBinding

The use of IsExpandableBinding would be similar as shown for the IsExpandedBinding.

A complete example of using RadTreeListView's IsExpandedBinding property is available in the TreeListView's OnDemandDataLoading demo.