EgtWPFLib/EgtPopup.xaml.vb

Imports System.Windows.Controls.Primitives
Imports System.Windows.Interop

Public Class EgtPopup
   Inherits Popup

   ''' <summary>			
   ''' Is Topmost dependency property			
   ''' </summary>			
   Public Shared ReadOnly IsTopmostProperty As DependencyProperty = DependencyProperty.Register("IsTopmost", GetType(Boolean), GetType(EgtPopup), New FrameworkPropertyMetadata(False, New PropertyChangedCallback(AddressOf OnIsTopmostChanged)))

   Private _appliedTopMost As System.Nullable(Of Boolean)
   Private _alreadyLoaded As Boolean
   Private _parentWindow As Window

   ''' <summary>			
   ''' Get/Set IsTopmost			
   ''' </summary>			
   Public Property IsTopmost() As Boolean
      Get
         Return CBool(GetValue(IsTopmostProperty))
      End Get
      Set(value As Boolean)
         SetValue(IsTopmostProperty, value)
      End Set
   End Property

   ''' <summary>			
   ''' ctor			
   ''' </summary>			
   Public Sub New()
      ' Chiamata richiesta dal Wpf
      InitializeComponent()
      'AddHandler Me.Loaded, AddressOf OnPopupLoaded
      'AddHandler Me.Unloaded, AddressOf OnPopupUnloaded
   End Sub


   'Private Sub OnPopupLoaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
   '   If _alreadyLoaded Then
   '      Return
   '   End If

   '   _alreadyLoaded = True

   '   If Child IsNot Nothing Then
   '      Child.[AddHandler](PreviewMouseLeftButtonDownEvent, New MouseButtonEventHandler(AddressOf OnChildPreviewMouseLeftButtonDown), True)
   '   End If

   '   _parentWindow = Window.GetWindow(Me)

   '   If _parentWindow Is Nothing Then
   '      Return
   '   End If

   '   AddHandler _parentWindow.Activated, AddressOf OnParentWindowActivated
   '   AddHandler _parentWindow.Deactivated, AddressOf OnParentWindowDeactivated

   'End Sub

   'Private Sub OnPopupUnloaded(sender As Object, e As RoutedEventArgs) Handles Me.Unloaded
   '   If _parentWindow Is Nothing Then
   '      Return
   '   End If
   '   RemoveHandler _parentWindow.Activated, AddressOf OnParentWindowActivated
   '   RemoveHandler _parentWindow.Deactivated, AddressOf OnParentWindowDeactivated

   'End Sub

   'Private Sub OnParentWindowActivated(sender As Object, e As EventArgs)
   '   Debug.WriteLine("Parent Window Activated")
   '   SetTopmostState(True)
   'End Sub

   'Private Sub OnParentWindowDeactivated(sender As Object, e As EventArgs)
   '   Debug.WriteLine("Parent Window Deactivated")

   '   If IsTopmost = False Then
   '      SetTopmostState(IsTopmost)
   '   End If
   'End Sub

   'Private Sub OnChildPreviewMouseLeftButtonDown(sender As Object, e As MouseButtonEventArgs)
   '   Debug.WriteLine("Child Mouse Left Button Down")

   '   SetTopmostState(True)

   '   If Not _parentWindow.IsActive AndAlso IsTopmost = False Then
   '      _parentWindow.Activate()
   '      Debug.WriteLine("Activating Parent from child Left Button Down")
   '   End If
   'End Sub

   Private Shared Sub OnIsTopmostChanged(obj As DependencyObject, e As DependencyPropertyChangedEventArgs)
      Dim thisobj = DirectCast(obj, EgtPopup)

      thisobj.SetTopmostState(thisobj.IsTopmost)
   End Sub

   Protected Overrides Sub OnOpened(e As EventArgs)
      SetTopmostState(IsTopmost)
      MyBase.OnOpened(e)
   End Sub

   Private Sub SetTopmostState(isTop As Boolean)
      ' Don’t apply state if it’s the same as incoming state			
      If _appliedTopMost.HasValue AndAlso _appliedTopMost = isTop Then
         Return
      End If

      If Child Is Nothing Then
         Return
      End If

      Dim hwndSource = TryCast(PresentationSource.FromVisual(Child), HwndSource)

      If hwndSource Is Nothing Then
         Return
      End If
      Dim hwnd = hwndSource.Handle

      Dim rect As WinApi.RECT

      If Not WinApi.GetWindowRect(hwnd, rect) Then
         Return
      End If

      Debug.WriteLine("setting z-order " & isTop)

      If isTop Then
         WinApi.SetWindowPos(hwnd, WinApi.HWND_TOPMOST, 0, 0, 0, 0, _
            WinApi.TOPMOST_FLAGS)
      Else
         ' Z-Order would only get refreshed/reflected if clicking the			
         ' the titlebar (as opposed to other parts of the external			
         ' window) unless I first set the popup to HWND_BOTTOM			
         ' then HWND_TOP before HWND_NOTOPMOST			
         WinApi.SetWindowPos(hwnd, WinApi.HWND_BOTTOM, 0, 0, 0, 0, _
            WinApi.TOPMOST_FLAGS)
         WinApi.SetWindowPos(hwnd, WinApi.HWND_TOP, 0, 0, 0, 0, _
            WinApi.TOPMOST_FLAGS)
         WinApi.SetWindowPos(hwnd, WinApi.HWND_NOTOPMOST, 0, 0, 0, 0, _
            WinApi.TOPMOST_FLAGS)
      End If

      _appliedTopMost = isTop
   End Sub

End Class