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ExpandCollapsePattern Class

Represents controls that visually expand to display content and collapse to hide content.

Namespace:  System.Windows.Automation
Assembly:  UIAutomationClient (in UIAutomationClient.dll)

public class ExpandCollapsePattern : BasePattern

Aggregate controls—built with child objects that provide the UI for expand/collapse functionality—must support the ExpandCollapsePattern control pattern while their child elements do not. For example, a combo box control is built with a combination of list box, button, and edit controls, but it is only the parent combo box that must support the ExpandCollapsePattern.


A menu control, even though an aggregate of individual menu items, is an exception to this rule. The menu items support the ExpandCollapsePattern control pattern, but the parent menu control does not. A similar exception applies to the tree and tree item controls.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0