Selection
RadTabControl exposes several useful properties and events, which can help you to work with items selection.
Properties
By using the SelectedIndex property, you can get or set the index of the currently selected tab item.
By using the SelectedItem property, you can get or set the currently selected tab item. The reference you are passing should be to an instance of RadTabItem that has already been added to the Items collection of the RadTabControl.
If your tab control is bound to a custom collection, then the property SelectedItem will not return RadTabItem as you might expect, but an item of the type the source collection contains i.e. Person, TabModel etc.
Another way to select a certain tab item is by using the RadTabItem’s IsSelected property. This is a Boolean property and when set to True, that specific tab item is selected, while the previous one gets deselected.
Use the SelectedContent property to get or set the content of the currently selected tab item. Please note that, when you set this property you will replace the content of the currently selected tab item, but the selected tab item will stay the same.
The items counting is zero based, meaning that the index of the first tab items is 0, the index of the second item is 1 and so on. If you want to clear the selection just set the property SelectedIndex to -1.
Events
RadTabControl provides two events in regards to its selection: PreviewSelectionChanged and SelectionChanged. The first one is raised before the selection is complete. Marking the event as handled will basically revert the selection.
Example 1: Subscribing to the PreviewSelectionChanged Event
<telerik:RadTabControl x:Name="radTabControl" SelectedIndex="1" PreviewSelectionChanged="radTabControl_PreviewSelectionChanged">
</telerik:RadTabControl>
Example 2: Handling the PreviewSelectionChanged Event
private void radTabControl_PreviewSelectionChanged(object sender, Telerik.Windows.Controls.RadSelectionChangedEventArgs e)
{
e.Handled = true;
}
Private Sub radTabControl_PreviewSelectionChanged(ByVal sender As Object, ByVal e As Telerik.Windows.Controls.RadSelectionChangedEventArgs)
e.Handled = True
End Sub
The SelectionChanged event is raised after the selection has already completed.
Example 3: Subscribing to the SelectionChanged Event
<telerik:RadTabControl x:Name="radTabControl" SelectedIndex="1" SelectionChanged="radTabControl_SelectionChanged" />
Example 4: Implementing the SelectionChanged Event Handler
private void radTabControl_SelectionChanged( System.Object sender, System.Windows.RoutedEventArgs e )
{
RadSelectionChangedEventArgs selectionArgs = ( RadSelectionChangedEventArgs )e;
MessageBox.Show( “The selected tab item is ” + ( ( RadTabItem )selectionArgs.AddedItems[ 0 ] ).Header.ToString() );
}
Private Sub radTabControl_SelectionChanged( ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
Dim selectionArgs As RadSelectionChangedEventArgs = DirectCast(e,RadSelectionChangedEventArgs)
MessageBox.Show("The selected tab item is " + DirectCast(selectionArgs.AddedItems(0), RadTabItem).Header.ToString() )
End Sub
If your tab control is bound to a custom collection, the code above will fail with InvalidCastException, because the AddedItems collection will no longer contain items of type RadTabItem and the explicit cast will fail. The collection will contain items that are of the same type that the source collection contains i.e. Person, TabModel etc.