//////////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// This function is not used by the sample, but it shows an alternative approach to building up
// the cache of hyperlinks. Depending on the action taken by the target app when providing data
// to be stored in the cache of results, different approaches taken by the UIA client can have
// different performance benefits.
//
//////////////////////////////////////////////////////////////////////////////////////////////////////////////
private void BuildListOfHyperlinksFromWindowInternalAlternateApproach(bool fSearchLinkChildren)
{
// If we're already building up a list of links, ignore this request to refresh the list.
// (A shipping app might consider queueing this request in order to refresh the list again
// once the in-progress refreshing action is complete.)
if (_fRefreshInProgress)
{
return;
}
_fRefreshInProgress = true;
// First build a cache request in the same way as done elsewhere in the sample.
// This means that for each element returned following the search, they will
// have their name, bounding rect and Invoke pattern cached.
IUIAutomationCacheRequest cacheRequest = _automation.CreateCacheRequest();
cacheRequest.AddProperty(_propertyIdName);
cacheRequest.AddProperty(_propertyIdBoundingRectangle);
cacheRequest.AddPattern(_patternIdInvoke);
// At this point elsewhere in the sample, we specified that we only wanted data
// for the hyperlink elements (and optionally their children) cached. In this
// approach here, we will say that we want data for ALL descendants of the
// found elements cached.
cacheRequest.TreeScope = TreeScope.TreeScope_Descendants;
// Now create a property condition as we've done elsewhere, to say that we're only
// interested in elements which are in the Control view and are hyperlinks.
IUIAutomationCondition conditionControlView = _automation.ControlViewCondition;
IUIAutomationCondition conditionHyperlink = _automation.CreatePropertyCondition(_propertyIdControlType, _controlTypeIdHyperlink);
IUIAutomationCondition condition = _automation.CreateAndCondition(conditionControlView, conditionHyperlink);
// Now unlike steps we took elsewhere, specify that the cache request should
// have an additional filter of the property condition we just created.
cacheRequest.TreeFilter = condition;
// Elsewhere in the sample, we called FindAllBuildCache(). This returned an array of hyperlink
// elements with their data cached, (and optinally their children with cache data too.) This
// CacheLinksFromWindow() function takes a different approach. The element that is returned
// from the call to BuildUpdatedCache() below is the browser element with some data cached.
// But the returned element will have an array of cached child elements, and each of those
// elements will by the hyperlinks we need. So the cache request here has specified through
// its tree filter that we're only interest in hyperlinks, whereas elsewhere in this sample,
// we supplied that condition in the search call we made. How much difference this makes to
// the performance of calls depends on the action taken by the target application.
// *** Note, using this appoach, we can't also cache data for the direct children of the
// hyperlinks as we did elsewhere in the sample. So whether this approach is practical
// depends on the needs of the client application.
// Note that with a property conditions, it's not possible to request that the set of elements
// returned from a search are all elements which have a control type of hyperlink OR whose parent
// has a control type of hyperlink.
// Get a handle to the window of interest.
IntPtr hwnd = Win32.FindWindow(strBrowserWindowClass, null);
if (hwnd != IntPtr.Zero)
{
IUIAutomationElement elementBrowser = _automation.ElementFromHandleBuildCache(hwnd, cacheRequest);
if (elementBrowser != null)
{
_linkItems.Clear();
IUIAutomationElementArray arrayChildren = elementBrowser.GetCachedChildren();
if (arrayChildren != null)
{
int cElements = arrayChildren.Length;
// Process each returned hyperlink element.
for (int idxElement = 0; idxElement < cElements; idxElement++)
{
IUIAutomationElement elementChild = arrayChildren.GetElement(idxElement);
// Take the same action elsewhere in the sample to present the hyperlink
// in the sample app UI.
string strLinkName = GetCachedDataFromElement(elementChild, fSearchLinkChildren);
if (strLinkName != null)
{
strLinkName = strLinkName.Trim();
LinkItem item = new LinkItem();
item.linkName = strLinkName;
item.element = elementChild;
_linkItems.Add(item);
}
}
// Notify the main UI thread that a list of links is ready for processing. Do not block in this call.
_listViewLinks.BeginInvoke(_UIUpdateDelegate, _linkItems);
}
}
}
// Allow another refresh to be performed now.
_fRefreshInProgress = false;
}
