NavBarViewBase.ItemSelecting Event

Fires before an item is selected.

Namespace: DevExpress.Xpf.NavBar

Assembly: DevExpress.Xpf.NavBar.v21.2.dll

NuGet Package: DevExpress.Wpf.NavBar

Declaration

C#

public event NavBarItemSelectingEventHandler ItemSelecting

VB.NET

Public Event ItemSelecting As NavBarItemSelectingEventHandler

Event Data

The ItemSelecting event's data class is NavBarItemSelectingEventArgs. The following properties provide information specific to this event:

Property	Description
Cancel	Gets or sets a value indicating whether the operation which raised an event should be canceled.
Handled	Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
NewGroup	Gets a group object containing an item that is going to be selected.
NewItem	Gets an item object that is going to be selected.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
PrevGroup	Gets the group containing the previously selected item.
PrevItem	Gets the previously selected item.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.

The event data class exposes the following methods:

Method	Description
InvokeEventHandler(Delegate, Object)	When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)	When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.

Remarks

The ItemSelecting event occurs when an item is going to be selected within the NavBarControl. This event allows you to cancel item selection, if required.

To learn more, see the Clicking and Selecting Items topic.

Example

In this example, the NavBarViewBase.ItemSelecting event is handled, to invoke a confirmation dialog allowing the selection of a specific item (‘Private’) to be canceled.

View Example

Window1.xaml.cs

private void navBar_ItemSelecting(object sender, NavBarItemSelectingEventArgs e){
    if (e.NewItem.Content.ToString() == "Private"){
        MessageBoxResult result = MessageBox.Show("Are you sure to select the 'Private' item?", "Confirm Dialog", MessageBoxButton.YesNo);
        e.Cancel = (result == MessageBoxResult.No);
    }
}

Window1.xaml.vb

Private Sub navBar_ItemSelecting(ByVal sender As Object, ByVal e As NavBarItemSelectingEventArgs)
    If e.NewItem.Content.ToString() = "Private" Then
        Dim result As MessageBoxResult = MessageBox.Show("Are you sure to select the 'Private' item?", "Confirm Dialog", MessageBoxButton.YesNo)
        e.Cancel = (result = MessageBoxResult.No)
    End If
End Sub