Implementing the UI Automation Transform Control Pattern

Article
11/03/2006

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

The TransformPattern control pattern is used to support controls that can be moved, resized, or rotated within a two-dimensional space. 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 ITransformProvider
Exceptions
Related Topics

Implementation Guidelines and Conventions

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

Support for this control pattern is not limited to objects on the desktop. This control pattern must also be supported by the children of a container object if the children can be moved, resized, or rotated freely within the boundaries of the container.
An object cannot be moved, resized, or rotated such that its resulting screen location would be completely outside the coordinates of its container and therefore inaccessible to the keyboard or mouse (for example, when a top-level window is moved off-screen or a child object is moved outside the boundaries of the container's viewport). In these cases, the object is placed as close to the requested screen coordinates as possible with the top or left coordinates overridden to be within the container boundaries.
For multi-monitor systems, if an object is moved, resized, or rotated completely outside the combined desktop screen coordinates, the object is placed on the primary monitor as close to the requested coordinates as possible.
All parameters and property values are absolute and independent of locale.

Required Members for ITransformProvider

The following properties and methods are required for implementing ITransformProvider.

Required members	Member type	Notes
CanMove	Property	None
CanResize	Property	None
CanRotate	Property	None
Move	Method	None
Resize	Method	None
Rotate	Method	None

This control pattern has no associated events.

Exceptions

Providers must throw the following exceptions.

Exception Type	Condition
InvalidOperationException	Move If the CanMoveProperty is false.
InvalidOperationException	Resize If the CanResizeProperty is false.
InvalidOperationException	Rotate If the CanRotateProperty is false.

InvalidOperationException

Move