UI Automation Support for the Thumb Control Type


This documentation is intended for .NET Framework developers who want to use the managed UI Automation classes defined in the System.Windows.Automation namespace. For the latest information about UI Automation, see Windows Automation API: UI Automation.

This topic provides information about UI Automation support for the Thumb control type. In UI Automation, a control type is a set of conditions that a control must meet in order to use the ControlTypeProperty property. The conditions include specific guidelines for UI Automation tree structure, UI Automation property values, and control patterns.

Thumb controls provide the functionality that enables a control to be moved (or dragged), such as a scroll bar button, or resized, such as a window resizing widget. Thumb controls can also be implemented as movable borders of panes. Note that it does not provide drag-and-drop functionality. Thumb controls can receive mouse focus but usually not keyboard focus. The control developer must implement the control so that it acts appropriately (can be dragged or resized).

The following sections define the required UI Automation tree structure, properties, control patterns, and events for the Thumb control type. The UI Automation requirements apply to all thumb controls, whether Windows Presentation Foundation (WPF), Win32, or Windows Forms.

Required UI Automation Tree Structure

The following table depicts the control view and the content view of the UI Automation tree that pertains to thumb controls and describes what can be contained in each view. For more information on the UI Automation tree, see UI Automation Tree Overview.

Control View Content View
Thumb - Not applicable

Thumb controls never appear in Content View because they only exist for being manipulated with a mouse. Their functionality is exposed though another control pattern, such as Scroll Pattern, Transform Pattern, or RangeValue Pattern, being supported on the Thumb container.

Required UI Automation Properties

The following table lists the UI Automation properties whose value or definition is especially relevant to thumb controls. For more information on UI Automation properties, see UI Automation Properties for Clients.

UI Automation Property Value Notes
AutomationIdProperty See notes. The value of this property needs to be unique across all controls in an application.
BoundingRectangleProperty See notes. The outermost rectangle that contains the whole control.
ClickablePointProperty See notes. Any point within the visible client area of the Thumb control.
IsKeyboardFocusableProperty See notes. If the control can receive keyboard focus, it must support this property.
NameProperty Null The Thumb control is not available in the Content View of the UI Automation tree so it does not require a name.
LabeledByProperty Null Thumb controls never have a label.
ControlTypeProperty Thumb This value is the same for all UI frameworks.
LocalizedControlTypeProperty "thumb" Localized string corresponding to the Thumb control type.
IsContentElementProperty False The Thumb control is never content.
IsControlElementProperty True The Thumb control must always be a control.

Required UI Automation Control Patterns

The following table lists the UI Automation control patterns required to be supported by thumb controls. For more information on control patterns, see UI Automation Control Patterns Overview.

Control Pattern/Pattern Property Support/Value Notes
ITransformProvider Required Enables the thumb control to be moved on the screen.

Required UI Automation Events

The following table lists the UI Automation events required to be supported by all thumb controls. For more information about events, see UI Automation Events Overview.

UI Automation Event Support Notes
BoundingRectangleProperty property-changed event. Required None
IsOffscreenProperty property-changed event. Required None
IsEnabledProperty property-changed event. Required None
AutomationFocusChangedEvent Required None
StructureChangedEvent Required None

See also