WPF/XAML NotifyIcon and Taskbar (System Tray) Popup Window

• The MouseLeave event is the crux of this class, so I will begin here:
  In order to achieve the popup window behaviour I wanted, I had to build functionality on top of a Windows forms NotifyIcon to add a MouseLeave event. By default, the NotifyIcon only has mouse events for: MouseClick, MouseDoubleClick, MouseDown, MouseMove and MouseUp. To further complicate the problem, I did not want the new MouseLeave event to fire immediately, but rather allow for a delay before firing. This delay is essential to the Popup Window in the WpfXamlPopup project as it allows a time buffer for when the mouse moves off of the NotifyIcon in the taskbar, which enables three important items:
  • The user can move off and back over the icon in a short period of time without the popup window closing (e.g. if the user accidentally moves the mouse off and back over the icon; or leaves the icon briefly and then changes his/her mind and returns to the icon.
  • Eliminates flicker/flashing when the mouse is hovering on the edge of the icon and sometimes gets a repeating hit/no hit scenario.
  • The user can move from the icon to the popup window without the popup window closing, i.e., if the user moves from the icon to the popup in less than the delay time, then the popup window remains open for a seamless transition.
• ExtendedNotifyIcon(int millisecondsToDelayMouseLeaveEvent) is the constructor and sets up an instance of a Windows Forms NotifyIcon control and associates the MouseMove event used for tracking the mouse position. The constructor also sets up the delayMouseLeaveEventTimer timer which is used to time the delay between when the mouse leaves/exits from over the icon and the MouseLeave event firing. A chained constructor sets the default delay at 100 milliseconds.
• The targetNotifyIcon_MouseMove method intercepts MouseMove events on the NotifyIcon and tracks the position of the mouse on the screen. It also initiates the timer to start (delayMouseLeaveEventTimer.Start). When the timer fires, it calls method delayMouseLeaveEventTimer_Tick which checks to see if the mouse is still positioned over the NotifyIcon. If it is, the method ignores any action. If it is not, it will raise the MouseLeave event. It is important to recognize that this works for 2 main reasons:
  • No action is taken if the timer expires and the mouse is still hovering over the NotifyIcon.
  • When the mouse moves over the icon, it constantly resets the timer and tracks the mouse - this means that the timer for the leave event will initiate for the full duration as the mouse exits from over the icon.
• The StartMouseLeaveTimer and StopMouseLeaveEventFromFiring methods provide manual overrides to the calling code for the custom MouseLeave event.
• The IDisposable Interface: If the Windows NotifyIcon is not disposed, it will remain visible after the application terminates and will only disappear once the user moves the mouse over the icon.

• LinearGradientBrush: to generate the graded background of the popup window.
• OuterGlowBitmapEffect: to generate the shadow around the window to make it stand out from the background.
• MainGridBorder: A style that sets the rounded corners, border and default background.

• The two storyboards <Storyboard x:Key="gridFadeInStoryBoard"> and <Storyboard x:Key="gridFadeOutStoryBoard"> simply animate the main grid in and out of view to provide a fade in/out effect. These are manipulated in the code behind (see below for more information).
• The <Grid x:Name="uiGridMain" Margin="10"> is the "frame" for the popup window and defines the areas for the splitter lines, buttons and window content. It is styled using the resource definition MainGridBorder in MainGridStyleRD.xaml
• The SlickToggleButtons are defined in SlickButtonRD.xaml and are used in the control box options for pinning and closing the popup.
• A simple Label provides the popup window title.
• Two StackPanels define the main content area of the window.
  • The first houses the radio buttons for switching between icon images in the taskbar
  • The second to contain a selection of buttons that could be used for various actions on the popup window.

MainNotifyWindow.cs:

• MainNotifyWindow() is the constructor and sets up the popup application by:
  • adding the NotifyIcon to the taskbar and registering the relevant events to invoke the popup window
  • setting the location of the popup window to the bottom right of the screen
  • setting the default state of the popup window to hidden by setting the window and the grid's opacity to 0
  • caching the required animations for the popup window and wiring up the events to actions when for when the animations complete
• SetNotifyIcon(string iconPrefix) changes the physical icon by accepting a prefix and appending Orb.ico to generate the name of an icon that has been built in to the resource file. e.g. "BlueOrb.Ico" which is then retrieved using the pack:// URI notation and assigned to the NotifyIcon.
• SetWindowToBottomRightOfScreen() positions the popup window in the bottom right of the screen.
• extendedNotifyIcon_OnShowWindow() handles the event fired when the mouse moves over the NotifyIcon in the taskbar. If there is no animation executing (uiGridMain.Opacity > 0 && uiGridMain.Opacity < 1), the handler begins the animation storyboard to fade the popup window in to view. If this is the case, the popup window and main grid are presented immediately to give the user instant access to the popup window. This scenario typically occurs when the user unknowingly moves off of the NotifyIcon, see's the popup window staring to fade out, and then quickly moves focus back over the icon to "recover" the window.
• extendedNotifyIcon_OnHideWindow() handles the event fired when the mouse leaves the NotifyIcon in the taskbar or when the mouse leaves the popup window. If the window is not pinned open, the handler begins the animation storyboard to fade the popup window out of view. As per the extendedNotifyIcon_OnShowWindow() method above, this handler only animates when the popup window is fully visible in order to avoid resetting the window's opacity to full, effectively restarting the animation, causing a horrible flicker.
• uiWindowMainNotification_MouseEnter(...) handles the event fired when the mouse enters the popup window. In this case, the user obviously wants to interact with the window and all "closing/fade out" events are cancelled and the window's main grid set to full opacity.
• uiWindowMainNotification_MouseLeave(...) handles the event fired when the mouse leave's the popup window. In this case, the user is assumed to have completed his work with the popup and the instruction is issues to fade the popup window out of view.
• gridFadeOutStoryBoard_Completed(...) this event ensures that the window is out of view by setting its Opacity = 0;
• gridFadeInStoryBoard_Completed(...) this event ensures that the window is fully visible after it has faded in by setting it's Opacity = 1;
• PinButton_Click(...) ensures that the right image is shown on the pin button for button's state (checked / unchecked)
• colourRadioButton_Click(...) switches the image used for the NotifyIcon in the taskbar
• CloseButton_Click(...) Performs necessary cleanup of the taskbar icon and closes the application