IUIAutomationTextRange::ExpandToEnclosingUnit method

Normalizes the text range by the specified text unit. The range is expanded if it is smaller than the specified unit, or shortened if it is longer than the specified unit.

Syntax


HRESULT ExpandToEnclosingUnit(
  [in]  TextUnit textUnit
);

Parameters

textUnit [in]

Type: TextUnit

The text unit, such as line or paragraph.

Return value

Type: HRESULT

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

Remarks

Client applications such as screen readers use this method to retrieve the full word, sentence, or paragraph that exists at the insertion point or caret position.

Despite its name, the ExpandToEnclosingUnit method does not necessarily expand a text range. Instead, it "normalizes" a text range by moving the endpoints so that the range encompasses the specified text unit. The range is expanded if it is smaller than the specified unit, or shortened if it is longer than the specified unit. If the range is already an exact quantity of the specified units, it remains unchanged. The following diagram shows how ExpandToEnclosingUnit normalizes a text range by moving the endpoints of the range.

Diagram showing endpoint positions before and after a call to ExpandToEnclosingUnit

ExpandToEnclosingUnit defaults to the next largest text unit supported if the specified text unit is not supported by the control. The order, from smallest unit to largest, is as follows:

  • Character
  • Format
  • Word
  • Line
  • Paragraph
  • Page
  • Document

ExpandToEnclosingUnit respects both visible and hidden text.

Range behavior when unit is TextUnit::Format

TextUnit::Format as a unit value positions the boundary of a text range to expand or move the range based on shared text attributes (format) of the text within the range. However, using the format text unit will not move or expand a text range across the boundary of an embedded object, such as an image or hyperlink. For more info, see UI Automation Text Units or UI Automation Support for Textual Content.

Requirements

Minimum supported client

Windows 7, Windows Vista with SP2 and Platform Update for Windows Vista, Windows XP with SP3 and Platform Update for Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2008 R2, Windows Server 2008 with SP2 and Platform Update for Windows Server 2008, Windows Server 2003 with SP2 and Platform Update for Windows Server 2008 [desktop apps only]

Header

UIAutomationClient.h (include UIAutomation.h)

IDL

UIAutomationClient.idl

See also

Reference
IUIAutomationTextRange
Conceptual
UI Automation Support for Textual Content

 

 

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