IUIAutomationExpandCollapsePattern::Expand method (uiautomationclient.h)

Displays all child nodes, controls, or content of the element.

Syntax

HRESULT Expand();

Return value

Type: HRESULT

If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

This is a blocking method that returns after the element has been expanded.

There are cases when a element that is marked as a leaf node might not know whether it has children until either the IUIAutomationExpandCollapsePattern::Collapse or the IUIAutomationExpandCollapsePattern::Expand method is called. This behavior is possible with a tree view control that does delayed loading of its child items. For example, Microsoft Windows Explorer might display the expand icon for a node even though there are currently no child items; when the icon is clicked, the control polls for child items, finds none, and removes the expand icon. In these cases clients should listen for a property-changed event on the IUIAutomationExpandCollapsePattern::CurrentExpandCollapseState property.

Requirements

See also

IUIAutomationExpandCollapsePattern