Registers a method (in an event handler group) that handles when the active text position changes.
HRESULT AddActiveTextPositionChangedEventHandler( TreeScope scope , IUIAutomationCacheRequest *cacheRequest, IUIAutomationActiveTextPositionChangedEventHandler *handler );
The scope of events to be handled; that is, whether they are on the element itself, or on its ancestors and descendants.
A pointer to a cache request, or NULL if no caching is wanted.
A pointer to the object that handles the active text position changed event.
If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.
Before implementing an event handler, you should be familiar with the threading issues described in Understanding Threading Issues.
Active text position is indicated by a navigation event within or between read-only text elements (such as web browsers, Portable Document Format (PDF) documents, or EPUB documents) using bookmarks (or fragment identifiers to refer to a location within a resource). Examples include:
- Navigating to a bookmark within the same web page
- Navigating to a bookmark on a different web page
- Activating a link to a different location within the same PDF
- Activating a link to a different location within the same EPUB
For example, when a same page anchor (
<a href=”#C4”>Jump to Chapter 4</a> ... <h1><a name="C4">Chapter 4</a></h1>)
is invoked, the visual location is updated, but the UI Automation client remains at the original location. This results in actions such as text reading or move next item commands starting from the original location, not the new location.
Similarly, activating a new page URI (with a fragment identifier: (
<a href=”www.blah.com#C4”>Jump to Chapter 4</a>)) loads the new page and jumps to the specified bookmark, but leaves the UI Automation clients at the top of the page.
|Minimum supported client||Windows 10, version 1809 [desktop apps only]|
|Minimum supported server||Windows Server, version 1709 [desktop apps only]|
|Header||uiautomationclient.h (include UIAutomation.h)|