Implementing the UI Automation Selection Control Pattern

This topic introduces guidelines and conventions for implementing ISelectionProvider, including information about events and properties. Links to additional references are listed at the end of the topic.

The SelectionPattern control pattern is used to support controls that act as containers for a collection of selectable child items. The children of this element must implement ISelectionItemProvider. For examples of controls that implement this control pattern, see Control Pattern Mapping for UI Automation Clients.

This topic contains the following sections.

• Implementation Guidelines and Conventions
• Required Members for ISelectionProvider
• Exceptions
• Related Topics

Implementation Guidelines and Conventions

When implementing the Selection control pattern, note the following guidelines and conventions:

• Controls that implement ISelectionProvider allow either single or multiple child items to be selected. For example, list box, list view, and tree view support multiple selections whereas combo box, slider, and radio button group support single selection.

• Controls that have a minimum, maximum, and continuous range, such as the Volume slider control, should implement IRangeValueProvider instead of ISelectionProvider.

• Single-selection controls that manage child controls that implement IRawElementProviderFragmentRoot, such as the Screen Resolution slider in the Display Properties dialog box or the Color Picker selection control from Microsoft Word (illustrated below), should implement ISelectionProvider; their children should implement both IRawElementProviderFragment and ISelectionItemProvider.

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Example of Color Swatch String Mapping

• Menus do not support SelectionPattern. If you are working with menu items that include both graphics and text (such as the Preview Pane items in the View menu in Microsoft Outlook) and need to convey state, you should implement IToggleProvider.

Required Members for ISelectionProvider

The following properties, methods, and events are required for the ISelectionProvider interface.

Required members	Type	Notes
CanSelectMultiple	Property	Should support property changed events using AddAutomationPropertyChangedEventHandler and RemoveAutomationPropertyChangedEventHandler.
IsSelectionRequired	Property	Should support property changed events using AddAutomationPropertyChangedEventHandler and RemoveAutomationPropertyChangedEventHandler.
GetSelection	Method	None
InvalidatedEvent	Event	Raised when a selection in a container has changed significantly and requires sending more addition and removal events than the InvalidateLimit constant permits.

The IsSelectionRequired and CanSelectMultiple properties can be dynamic. For example, the initial state of a control might not have any items selected by default, indicating that IsSelectionRequired is false. However, after an item is selected, the control must always have at least one item selected. Similarly, in rare cases, a control might allow multiple items to be selected on initialization, but subsequently allow only single selections to be made.

Exceptions

Providers must throw the following exceptions.

Exception Type	Condition
ElementNotEnabledException	If the control is not enabled.
InvalidOperationException	If the control is hidden.

See Also

Tasks

Support Control Patterns in a UI Automation Provider
Use Caching in UI Automation

Concepts

UI Automation Control Patterns Overview
UI Automation Control Patterns for Clients
Implementing the UI Automation SelectionItem Control Pattern
UI Automation Tree Overview