MM_ACM_FORMATCHOOSE
The
MM_ACM_FORMATCHOOSE message notifies an acmFormatChoose dialog hook function
before adding an element to one of the three drop-down list boxes. This message
allows an application to further customize the selections available through the
user interface.
MM_ACM_FORMATCHOOSE
wParam = (WPARAM) wDropDown
lParam = (LONG) lCustom
Parameters
wDropDown
Drop-down
listbox being initialized and a verify or add operation.
FORMATCHOOSE_CUSTOM_VERIFY
The lParam
parameter is a pointer to a WAVEFORMATEX structure to be added to the custom Name
drop-down list box.
FORMATCHOOSE_FORMAT_ADD
The lParam
parameter is a pointer to a buffer that will accept a WAVEFORMATEX
structure to be added to the Format drop-down list box. The application must
copy the format structure to be added into this buffer.
FORMATCHOOSE_FORMAT_VERIFY
The lParam
parameter is a pointer to a WAVEFORMATEX structure to be added to the Format drop-down
list box.
FORMATCHOOSE_FORMATTAG_ADD
The lParam
parameter is a pointer to a variable that will accept a waveform-audio format
tag to be added to the Format Tag drop-down list box.
FORMATCHOOSE_FORMATTAG_VERIFY
The lParam
parameter is a waveform-audio format tag to be listed in the Format Tag
drop-down list box.
lCustom
Value defined
by the listbox specified in the wParam parameter.
Return Values
Returns TRUE
if an application handles this message or FALSE otherwise.
Remarks
If the
application processes the FILTERCHOOSE_FORMAT_ADD operation, the size of the
memory buffer supplied in lParam will be determined from the acmMetrics function.
If your
application is processing a verify operation, it can prevent the dialog box
from listing this selection by calling the SetWindowLong function with nIndex
set to DWL_MSGRESULT and lNewLong set to FALSE (cast to a LONG
data type). To allow the dialog box to list this selection, call this function
with lNewLong set to TRUE.
If your
application is processing an add operation, it can indicate that no more
additions are required by calling the SetWindowLong function with nIndex
set to DWL_MSGRESULT and lNewLong set to FALSE (cast to a LONG
data type). To indicate more additions are required, call this function with lNewLong
set to TRUE.
See Also