protected override System.Collections.Generic.List <AutomationPeer> GetChildrenCore()
{
// If Ribbon is Collapsed, dont show anything in the UIA tree
if (OwningRibbon.IsCollapsed)
{
return(null);
}
List <AutomationPeer> children = new List <AutomationPeer>();
// Step1: Add QAT + Title + ContextualTabGroupHeaderItemsControl
if (OwningRibbon.QuickAccessToolBar != null)
{
AutomationPeer peer = CreatePeerForElement(OwningRibbon.QuickAccessToolBar);
if (peer != null)
{
children.Add(peer);
}
}
if (OwningRibbon.TitleHost != null)
{
AutomationPeer peer = CreatePeerForElement(OwningRibbon.TitleHost);
if (peer == null)
{
FrameworkElement titleHost = OwningRibbon.TitleHost as FrameworkElement;
if (titleHost != null)
{
peer = new RibbonTitleAutomationPeer(titleHost);
}
else
{
peer = new UIElementAutomationPeer(OwningRibbon.TitleHost);
}
}
children.Add(peer);
}
if (OwningRibbon.ContextualTabGroupItemsControl != null)
{
AutomationPeer peer = CreatePeerForElement(OwningRibbon.ContextualTabGroupItemsControl);
if (peer != null)
{
children.Add(peer);
}
}
// Step2: Add ApplicationMenu
if (OwningRibbon.ApplicationMenu != null)
{
AutomationPeer peer = CreatePeerForElement(OwningRibbon.ApplicationMenu);
if (peer != null)
{
children.Add(peer);
}
}
// Step3: Refresh RibbonTabHeaders
// RibbonTabHeaderItemsControl doesnt appear in the UIA Tree, but its children RibbonTabHeader appear as children of RibbonTab
// We need to ensure that RibbonTabHeader peers are created and refreshed manually here
if (OwningRibbon.RibbonTabHeaderItemsControl != null)
{
#if RIBBON_IN_FRAMEWORK
AutomationPeer peer = CreatePeerForElement(OwningRibbon.RibbonTabHeaderItemsControl);
if (peer != null)
{
peer.ForceEnsureChildren();
}
#else
// We are unable to use this commented piece of code because ForceEnsureChildren
// is an internal method in .Net 4.0. The public alternative is to use
// AutomationPeer.ResetChildrenCache. However this methods isn't appropriate to be
// called during a GetChildrenCore call because it causes a recursive call to the
// GetChildren call for the current AutomationPeer which is prohibited. For
// illustration here's a callstack.
// Exception:System.InvalidOperationException: Recursive call to Automation Peer API is not valid. at
// System.Windows.Automation.Peers.AutomationPeer.GetChildren() at
// System.Windows.Automation.Peers.AutomationPeer.isDescendantOf(AutomationPeer parent) at
// System.Windows.Automation.Peers.AutomationPeer.isDescendantOf(AutomationPeer parent) at
// System.Windows.Automation.Peers.AutomationPeer.ValidateConnected(AutomationPeer connectedPeer) at
// MS.Internal.Automation.ElementProxy.StaticWrap(AutomationPeer peer, AutomationPeer referencePeer) at
// System.Windows.Automation.Peers.AutomationPeer.UpdateChildrenInternal(Int32 invalidateLimit) at
// System.Windows.Automation.Peers.ItemsControlAutomationPeer.UpdateChildren() at
// Microsoft.Windows.Automation.Peers.RibbonAutomationPeer.GetChildrenCore() at
// Also note that this code path is hit only when the UIA client is listening for
// structure changed events. UI Spy for instance doesn't do this by default and
// hence you will not automatically see the above crash it in that case. You need
// to configure the events to include structure changed.
// -----------------------------------------------------------------------------------------
// AutomationPeer peer = CreatePeerForElement(OwningRibbon.RibbonTabHeaderItemsControl);
// if (peer != null)
// {
// peer.ForceEnsureChildren();
// }
// -----------------------------------------------------------------------------------------
// The strategy to create a new instance of the AutomationPeer is a workaround to
// the above limitation. It is important to create a new instance each time so
// that we guarantee that the children are in fact updated. A GetChildren call on
// a previously existing AutomationPeer will short circuit due to the _childrenValid
// flag. Hence the creation of a new AutomationPeer object each time around. Note
// that it is only this one AutomationPeer instanced that is created anew each time.
// The Peers for the descendents are not recreated.
AutomationPeer peer = new RibbonTabHeaderItemsControlAutomationPeer(OwningRibbon.RibbonTabHeaderItemsControl);
peer.GetChildren();
#endif
}
// Step4: Add RibbonTabs
List <AutomationPeer> ribbonTabs = base.GetChildrenCore();
if (ribbonTabs != null && ribbonTabs.Count > 0)
{
children.AddRange(ribbonTabs);
// This is required for the RibbonTabHeaderDataAutomationPeers to correctly
// connect to the parent RibbonTabDataAutomationPeer
for (int i = 0; i < ribbonTabs.Count; i++)
{
#if RIBBON_IN_FRAMEWORK
ribbonTabs[i].ForceEnsureChildren();
#else
ribbonTabs[i].GetChildren();
#endif
}
}
// Step5: Add HelpPane that appears next to TabPanel
UIElement helpPaneHost = OwningRibbon.HelpPaneHost;
if (helpPaneHost != null)
{
AutomationPeer peer = CreatePeerForElement(helpPaneHost);
if (peer == null)
{
FrameworkElement helpPaneHostFE = helpPaneHost as FrameworkElement;
if (helpPaneHostFE != null)
{
peer = new FrameworkElementAutomationPeer(helpPaneHostFE);
}
else
{
peer = new UIElementAutomationPeer(helpPaneHost);
}
}
children.Add(peer);
}
return(children);
}