UI Automation Tree Overview
Actualización: noviembre 2007
Assistive technology products and test scripts navigate the Automatización de la interfaz de usuario tree to gather information about the interfaz de usuario (UI) and its elements.
Within the Automatización de la interfaz de usuario tree there is a root element (RootElement) that represents the current desktop and whose child elements represent application windows. Each of these child elements can contain elements representing pieces of interfaz de usuario such as menus, buttons, toolbars, and list boxes. These elements in turn can contain elements such as list items.
The Automatización de la interfaz de usuario tree is not a fixed structure and is seldom seen in its totality because it might contain thousands of elements. Parts of it are built as they are needed, and it can undergo changes as elements are added, moved, or removed.
UI Automation providers support the Automatización de la interfaz de usuario tree by implementing navigation among items within a fragment, which consists of a root (usually hosted in a window) and a subtree. However, providers are not concerned with navigation from one control to another. This is managed by the Automatización de la interfaz de usuario core, using information from the default window providers.
Este tema contiene las secciones siguientes.
- Views of the Automation Tree
- Temas relacionados
Views of the Automation Tree
The Automatización de la interfaz de usuario tree can be filtered to create views that contain only those AutomationElement objects relevant for a particular client. This approach allows clients to customize the structure presented through Automatización de la interfaz de usuario to their particular needs.
The client has two ways of customizing the view: by scoping and by filtering. Scoping is defining the extent of the view, starting from a base element: for example, the application might want to find only direct children of the desktop, or all descendants of an application window. Filtering is defining the types of elements that are to be included in the view.
UI Automation providers support filtering by defining properties on elements, including the IsControlElementProperty and IsContentElementProperty properties.
Automatización de la interfaz de usuario provides three default views. These views are defined by the type of filtering performed; the scope of any view is defined by the application. In addition, the application can apply other filters on properties; for example, to include only enabled controls in a control view.
Raw View
The raw view of the Automatización de la interfaz de usuario tree is the full tree of AutomationElement objects for which the desktop is the root. The raw view closely follows the native programmatic structure of an application and therefore is the most detailed view available. It is also the base on which the other views of the tree are built. Because this view depends on the underlying interfaz de usuario framework, the raw view of a WPF button will have a different raw view than a Win32 button.
The raw view is obtained by searching for elements without specifying properties or by using the RawViewWalker to navigate the tree.
Control View
The control view of the Automatización de la interfaz de usuario tree simplifies the assistive technology product's task of describing the interfaz de usuario to the end user and helping that end user interact with the application because it closely maps to the interfaz de usuario structure perceived by an end user.
The control view is a subset of the raw view. It includes all interfaz de usuario items from the raw view that an end user would understand as interactive or contributing to the logical structure of the control in the interfaz de usuario. Examples of interfaz de usuario items that contribute to the logical structure of the interfaz de usuario, but are not interactive themselves, are item containers such as list view headers, toolbars, menus, and the status bar. Non-interactive items used simply for layout or decorative purposes will not be seen in the control view. An example is a panel that was used only to lay out the controls in a dialog but does not itself contain any information. Non-interactive items that will be seen in the control view are graphics with information and static text in a dialog. Non-interactive items that are included in the control view cannot receive keyboard focus.
The control view is obtained by searching for elements that have the IsControlElement property set to true, or by using the ControlViewWalker to navigate the tree.
Content View
The content view of the Automatización de la interfaz de usuario tree is a subset of the control view. It contains interfaz de usuario items that convey the true information in a user interface, including interfaz de usuario items that can receive keyboard focus and some text that is not a label on a interfaz de usuario item. For example, the values in a drop-down combo box will appear in the content view because they represent the information being used by an end user. In the content view, a combo box and list box are both represented as a collection of interfaz de usuario items where one, or perhaps more than one, item can be selected. The fact that one is always open and one can expand and collapse is irrelevant in the content view because it is designed to show the data, or content, that is being presented to the user.
The content view is obtained by searching for elements that have the IsContentElement property set to true, or by using the ContentViewWalker to navigate the tree.