DefaultAction Property

[This is preliminary documentation and subject to change.]

An object's DefaultAction property, retrieved by calling the IAccessible::get_accDefaultAction method, describes its primary method of manipulation from the user's viewpoint. Do not confuse the DefaultAction property with the object's Value property. Some controls, such as an edit field, might have a value but not a default action. The following list provides some common examples.

• A selected check box has a default action of "Uncheck" and a value of "Checked."
• A cleared check box has a default action of "Check" and a value of "Unchecked."
• A button labeled "Print" has a default action of "Press," with no value.
• A static text control or an edit control that shows "Printer" has no default action, but would have a value of "Printer."

The DefaultAction property is primarily for use by voice input and blind access utilities. For example, when a blind access utility encounters a custom control that it does not recognize, it can still provide a significant amount of information to the blind user, such as the object's name (like "Speed"), its role (like "Switch"), its default action, if supported (like "Adjust"), and the current value (like "High"). Of course, the client can also use OLE Automation to enumerate all the properties and methods that the object supports, but there could be very many and most can be obscure, so the DefaultAction property provides a simple method of succinctly conveying the operation that the user will most likely use.

Not all objects support the DefaultAction property; if the call to get_accDefaultAction returns the DISP_E_MEMBERNOTFOUND value, then the object has no default action. For example, objects that don't perform actions, like static text, won't have a default action.