Closed Event

Imports Infragistics.Windows.DockManager
Imports Infragistics.Windows.DockManager.Events

Private Sub ContentPane_Closing(ByVal sender As Object, ByVal e As PaneClosingEventArgs)
    Dim result As MessageBoxResult = MessageBox.Show(Me, "Can this pane be hidden?", "Close Pane", MessageBoxButton.YesNo, MessageBoxImage.Question)

    If MessageBoxResult.No = result Then
        e.Cancel = True
    End If
End Sub

Private Sub ContentPane_Closed(ByVal sender As Object, ByVal e As PaneClosedEventArgs)
    Dim cp As ContentPane = TryCast(e.OriginalSource, ContentPane)

    System.Diagnostics.Debug.WriteLine(cp.Header, "Closed")
End Sub

Private Sub InitializeDmClosePane(ByVal dockManager As XamDockManager)
    Dim split As New SplitPane()

    ' By default when a pane is closed, it 
    ' is just hidden. For some panes though 
    ' you may just want the pane to be removed. 
    ' The CloseAction can be used to control this. 
    Dim cpRemove As New ContentPane()
    cpRemove.CloseAction = PaneCloseAction.RemovePane
    cpRemove.Header = "Remove When Closed"
    split.Panes.Add(cpRemove)

    ' You can prevent a pane from being closed using 
    ' the AllowClose property. By default all panes 
    ' can be closed and when closed the Visibility 
    ' is changed to Collapsed. 
    Dim cpNever As New ContentPane()
    cpNever.AllowClose = False
    cpNever.Header = "Never Close"
    split.Panes.Add(cpNever)

    ' You can handle the Closing event to conditionally 
    ' prevent the pane from being closed. The Closed 
    ' event is fired after the pane has been closed 
    ' regardless of the CloseAction 
    Dim cpConditional As New ContentPane()
    cpConditional.Header = "Conditionally Close"
    AddHandler cpConditional.Closing, AddressOf Me.ContentPane_Closing
    AddHandler cpConditional.Closed, AddressOf Me.ContentPane_Closed
    split.Panes.Add(cpConditional)

    dockManager.Panes.Add(split)
End Sub