Implementing the UI Automation Window Control Pattern


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

The WindowPattern control pattern is used to support controls that provide fundamental window-based functionality within a traditional graphical user interface (GUI). Examples of controls that must implement this control pattern include top-level application windows, multiple-document interface (MDI) child windows, resizable split pane controls, modal dialogs and balloon help windows.

Implementation Guidelines and Conventions

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

  • To support the ability to modify both window size and screen position using UI Automation, a control must implement ITransformProvider in addition to IWindowProvider.

  • Controls that contain title bars and title bar elements that enable the control to be moved, resized, maximized, minimized, or closed are typically required to implement IWindowProvider.

  • Controls such as tooltip pop-ups and combo box or menu drop-downs do not typically implement IWindowProvider.

  • Balloon help windows are differentiated from basic tooltip pop-ups by the provision of a window-like Close button.

  • Full-screen mode is not supported by IWindowProvider as it is feature-specific to an application and is not typical window behavior.

Required Members for IWindowProvider

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

Required member Member type Notes
InteractionState Property None
IsModal Property None
IsTopmost Property None
Maximizable Property None
Minimizable Property None
VisualState Property None
Close Method None
SetVisualState Method None
WaitForInputIdle Method None
WindowClosedEvent Event None
WindowOpenedEvent Event None
WindowInteractionState Event Is not guaranteed to be ReadyForUserInteraction


Providers must throw the following exceptions.

Exception type Condition
InvalidOperationException SetVisualState

- When a control does not support a requested behavior.
ArgumentOutOfRangeException WaitForInputIdle

- When the parameter is not a valid number.

See also