IAccessible::get_accDefaultAction method (oleacc.h)

Article
02/22/2024

The IAccessible::get_accDefaultAction method retrieves a string that indicates the object's default action. Not all objects have a default action.

Syntax

HRESULT get_accDefaultAction(
  [in]          VARIANT varChild,
  [out, retval] BSTR    *pszDefaultAction
);

Parameters

[in] varChild

Type: VARIANT

Specifies whether the retrieved default action is performed by the object or of one of the object's child elements. This parameter is either CHILDID_SELF (to obtain information about the object) or a child ID (to obtain information about the object's child element). For more information about initializing the VARIANT structure, see How Child IDs Are Used in Parameters.

[out, retval] pszDefaultAction

Type: BSTR*

Address of a BSTR that receives a localized string that describes the default action for the specified object; if this object has no default action, the value is NULL.

Return value

Type: HRESULT

If successful, returns S_OK.

If not successful, returns one of the values in the table that follows, or another standard COM error code. Servers return these values, but clients must always check output parameters to ensure that they contain valid values. For more information, see Checking IAccessible Return Values.

Error	Description
S_FALSE	The specified object does not have a default action.
E_INVALIDARG	An argument is not valid.
DISP_E_MEMBERNOTFOUND	The specified object does not support this property.

Remarks

The retrieved string describes the action that is performed on an object, not what the object does as a result. For example, a toolbar button that prints a document has a default action of "Press" rather than "Prints the current document."

Do not confuse an object's default action with its value. For more information, see DefaultAction Property.

Only controls that perform actions support this method.

Note to server developers: Localize the string returned from this property.

Server Example

The following example code shows a possible implementation of this method for a custom list box. For simplicity, the strings are not localized.


HRESULT STDMETHODCALLTYPE AccServer::get_accDefaultAction( 
    VARIANT varChild,
    BSTR *pszDefaultAction)
{
    if (varChild.vt != VT_I4)
    {
        *pszDefaultAction = NULL;
        return E_INVALIDARG;
    }
    if (varChild.lVal == CHILDID_SELF)
    {
        *pszDefaultAction = SysAllocString(L"None.");
    }
    else
    {
        *pszDefaultAction = SysAllocString(L"Double-click");
    }
    return S_OK;
};

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	oleacc.h
Library	Oleacc.lib
DLL	Oleacc.dll
Redistributable	Active Accessibility 1.3 RDK on Windows NT 4.0 with SP6 and later and Windows 95