Assembly: PresentationFramework (in presentationframework.dll)
XML Namespace: http://schemas.microsoft.com/winfx/2006/xaml/presentation
/** @event */ public void add_ToolTipOpening (ToolTipEventHandler value) /** @event */ public void remove_ToolTipOpening (ToolTipEventHandler value)
In JScript, you can handle the events defined by a class, but you cannot define your own.
To prevent a tooltip from appearing in the UI, your handler for ToolTipOpening can mark the ToolTipEventArgs event data handled. Otherwise, the tooltip is displayed, using the value of the ToolTip property as the tooltip content. Another possible scenario is that you could write a handler that resets the value of the ToolTip property for the element that is the event source, just before the tooltip is displayed.
ToolTipOpening will not be raised if the value of ToolTip is a null reference (Nothing in Visual Basic) or otherwise unset. Do not deliberately set ToolTip to a null reference (Nothing in Visual Basic) while a tooltip is open or opening; this will not have the effect of closing the tooltip, and will instead create an undesirable visual artifact in the UI.
The ToolTipOpening event cannot be an EventTrigger in a style. This is because the identifier field of this event re-uses an implementation from a service that does not expose add/remove event methods for the service-level event.
Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter EditionThe Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.