Events

The RadTabbedWindow control exposes a number of events to let you easily customize its behavior.

Most of these events are inherited from the RadWindow control. As the RadTabbedWindow contains a TabbedWindowTabControl which inherits from RadTabControl, most of its events bubble to the window as well.

AddingNewTab

Occurs when a RadTabItem is being added via the 'Add' button in the UI. Its AddingNewTabEventArgs expose the following properties:

• Cancel: Gets or sets a value indicating whether adding the new tab via add button should be cancelled.

• Item: Gets or sets the newly added item. The type of the item depends on the scenario.

  If the RadTabbedWindow control is populated directly with RadTabItem elements, the Item property contains an object of type RadTabItem which you can customize or completely replace.

  Example 1: Handle the AddingNewTab event in data binding scenario

      private void RadTabbedWindow_AddingNewTab(object sender, TabControlAddingNewTabEventArgs e) 
      { 
          if (this.TotalTabCount > this.MaxTabCount) // replace with your cancel condition 
          { 
              e.Cancel = true; 
          } 
          else 
          { 
              e.Item = new Person("P " + this.Items.Count); 
          } 
      } 
  

      Private Sub RadTabbedWindow_AddingNewTab(ByVal sender As Object, ByVal e As TabControlAddingNewTabEventArgs) 
          If Me.TotalTabCount > Me.MaxTabCount Then ' replace with your cancel condition 
              e.Cancel = True 
          Else 
              e.Item = New Person("P " & Me.Items.Count) 
          End If 
      End Sub 
  

  If the ItemsSource of the control is populated (data binding scenario), the Item property will be empty (null) and you should manually set it to an object of your business type. Otherwise, no tab will added.

  Example 2: Handle the AddingNewTab event

      private void RadTabbedWindow_AddingNewTab(object sender, TabControlAddingNewTabEventArgs e) 
      { 
          RadTabItem tabItem = e.Item as RadTabItem; 
          if (tabItem != null) 
          { 
              tabItem.Header = "New tab"; 
              tabItem.Content = "Empty tab"; 
          }  
      } 
  

      Private Sub RadTabbedWindow_AddingNewTab(ByVal sender As Object, ByVal e As TabControlAddingNewTabEventArgs) 
          Dim tabItem As RadTabItem = TryCast(e.Item, RadTabItem) 
   
          If tabItem IsNot Nothing Then 
              tabItem.Header = "New tab" 
              tabItem.Content = "Empty tab" 
          End If 
      End Sub 
  

  If the Item property is left empty (null), no tab will be added.

If the provided Item's type does not match the data type of the current ItemsSource an exception will be thrown.

TabbedWindowCreating

Occurs when a new RadTabbedWindow is created via drag and drop and is about to be shown. Its TabbedWindowCreatingEventArgs expose the following properties:

• Cancel: Gets or sets a value indicating whether the creation of the new window should be cancelled.
• SourceWindow: The source window from which the drag drop operation is started.
• NewWindow: The new window created via drag drop operation.
• DraggedTab: The dragged RadTabItem from the source RadTabbedWindow. As of R2 2019 SP1, this property is obsolete and the DraggedItem property needs to be used instead.
• DraggedItem: The dragged RadTabItem in an unbound scenario or the dragged item (viewmodel) in a databinding scenario.

Example 3 demonstrates how you can cancel the creation of the new window or attach the same handler to its AddingNewTab event as that of the source window in an unbound scenario.

Example 3: Handle the TabbedWindowCreating event in an unbound scenario

private void MainWindow_TabbedWindowCreating(object sender, TabbedWindowCreatingEventArgs e) 
{ 
    var tab = e.DraggedItem as RadTabItem; 
    if (tab != null && tab.Header.ToString() == "Progress") // replace with your cancel condition 
    { 
        e.Cancel = true; 
    } 
    else 
    { 
        e.NewWindow.AddingNewTab += this.MainWindow_AddingNewTab; // the AddingNewTab handler of the main RadTabbedWindow 
    } 
} 

Private Sub MainWindow_TabbedWindowCreating(ByVal sender As Object, ByVal e As TabbedWindowCreatingEventArgs) 
    Dim tab = TryCast(e.DraggedItem, RadTabItem) 
    If tab IsNot Nothing AndAlso tab.Header.ToString() = "Progress" Then ' replace with your cancel condition 
        e.Cancel = True 
    Else 
        e.NewWindow.AddingNewTab += Me.MainWindow_AddingNewTab ' the AddingNewTab handler of the main RadTabbedWindow 
    End If 
End Sub 

You can also use the TabbedWindowCreating event to clear, update or replace the ItemsSource of the new window. Example 4 demonstrates how to do so in a databound scenario.

Example 4: Change the ItemsSource of the new window in a databinding scenario

private void MainWindow_TabbedWindowCreating(object sender, TabbedWindowCreatingEventArgs e) 
{ 
    var tabItem = e.DraggedItem as MyTabItem; 
    if (tabItem != null && tabItem.Header == "Progress") 
    { 
        e.NewWindow.ItemsSource = null;  
    } 
    else if (tabItem != null && tabItem.Header == "Microsoft") 
    { 
        var collection = e.NewWindow.ItemsSource as ObservableCollection<object>; 
        if (collection != null) 
        { 
            collection.Add(new MyTabItem() { Header = "My tab 1" }); 
            collection.Add(new MyTabItem() { Header = "My tab 2" }); 
        } 
    } 
    else 
    { 
        var collection = new ObservableCollection<Person>(); 
        collection.Add(new Person() { Name = "John Doe", Age = 23 }); 
        e.NewWindow.ItemsSource = collection; 
        e.NewWindow.DisplayMemberPath = "Name"; 
    } 
} 

Private Sub MainWindow_TabbedWindowCreating(ByVal sender As Object, ByVal e As TabbedWindowCreatingEventArgs) 
    Dim tabItem = TryCast(e.DraggedItem, MyTabItem) 
    If tabItem IsNot Nothing AndAlso tabItem.Header = "Progress" Then 
        e.NewWindow.ItemsSource = Nothing 
    ElseIf tabItem IsNot Nothing AndAlso tabItem.Header = "Microsoft" Then 
        Dim collection = TryCast(e.NewWindow.ItemsSource, ObservableCollection(Of Object)) 
        If collection IsNot Nothing Then 
            collection.Add(New MyTabItem() With {.Header = "My tab 1"}) 
            collection.Add(New MyTabItem() With {.Header = "My tab 2"}) 
        End If 
    Else 
        Dim collection = New ObservableCollection(Of Person) 
        collection.Add(New Person() With { 
            .Name = "John Doe", 
            .Age = 23 
        }) 
        e.NewWindow.ItemsSource = collection 
        e.NewWindow.DisplayMemberPath = "Name" 
    End If 
End Sub 

PreviewTabClosed

Occurs when a RadTabItem is about to be closed. This event can be cancelled by the PreviewTabChangedEventArgs's boolean Cancel property to True. The event arguments expose the TabItem which was changed and its DataContext, if any.

TabClosed

Occurs when a RadTabItem is closed. Its TabChangedEventArgs expose the TabItem which was changed and its DataContext, if any.

PreviewTabPinned

Occurs when a RadTabItem is about to be pinned. This event can be cancelled by the PreviewTabChangedEventArgs's boolean Cancel property to True. The event arguments expose the TabItem which was changed and its DataContext, if any.

TabPinned

Occurs when a RadTabItem is pinned. Its TabChangedEventArgs expose the TabItem which was changed and its DataContext, if any.

PreviewTabUnpinned

Occurs when a RadTabItem is about to be unpinned. This event can be cancelled by the PreviewTabChangedEventArgs's boolean Cancel property to True. The event arguments expose the TabItem which was changed and its DataContext, if any.

TabUnpinned

Occurs when a RadTabItem is unpinned. Its TabChangedEventArgs expose the TabItem which was changed and its DataContext, if any.

PreviewSelectionChanged

Handling this event by setting the RadSelectionChangedEventArgs' Handled property to True rollbacks the selection.

SelectionChanged

Occurs when a change has been made to the selection.

See Also

• Key Properties
• Styles and Templates