_CPSUICALLBACK callback function (compstui.h)
The _CPSUICALLBACK function type is used by CPSUI applications (including printer interface DLLs) for defining a callback function intended for use as a CPSUI message handler.
Syntax
_CPSUICALLBACK Cpsuicallback;
LONG Cpsuicallback(
PCPSUICBPARAM pCPSUICBParam
)
{...}
Parameters
pCPSUICBParam
CPSUI-supplied pointer to a CPSUICBPARAM structure.
Return value
A _CPSUICALLBACK-typed callback function must return one of the values listed in the following table. Each value indicates an action that CPSUI should perform.
| Return code | Description |
|---|---|
| CPSUICB_ACTION_ITEMS_APPLIED | The CPSUICBPARAM structure's Reason member was set to CPSUICB_REASON_APPLYNOW, and the callback function has successfully processed the current option values. |
| CPSUICB_ACTION_NO_APPLY_EXIT | The CPSUICBPARAM structure's Reason member was set to CPSUICB_REASON_APPLYNOW, but the callback function has detected invalid or incompatible option values. The callback function must display a dialog box telling the user of the problem. |
| CPSUICB_ACTION_NONE | No action by CPSUI is required. |
| CPSUICB_ACTION_OPTIF_CHANGED | The callback function has set the OPTIF_CHANGED flag in an OPTITEM structure to indicate that the selected option has changed, or that another OPTIF-prefixed flag has changed. |
| CPSUICB_ACTION_REINIT_ITEMS | The callback function has set the OPTIF_CHANGED flag in an OPTITEM structure to indicate that Flags or pData members of the associated OPTTYPE or OPTPARAM structure have changed. |
Remarks
Callback functions specified using the _CPSUICALLBACK function type are supplied by applications that use CPSUI to manage property sheet pages. If one of these callback functions is associated with a property sheet page, CPSUI calls it when user activity (such as changing the page's control focus, modifying option values, or clicking OK) is detected.
A _CPSUICALLBACK-typed callback function is assigned to a property sheet page by including its address in a COMPROPSHEETUI structure, which is passed to CPSUI's ComPropSheet function when the function code is CPSFUNC_ADD_PCOMPROPSHEETUI.
Additionally, callback functions can be assigned to extended push buttons through the use of EXTPUSH structures.
When one of these callback functions is called, it receives a pointer to a CPSUICBPARAM structure. This structure describes the current option settings for the page and indicates the user event that caused the function to be called. The callback function is responsible for validating and processing the settings. It should display a dialog box if a setting (or a combination of settings) is invalid. The function's return value indicates to CPSUI whether the page needs to be redisplayed or reinitialized.
Callback functions specified with this function type cannot be used if the DlgProc member of the DLGPAGE structure specifies an application-supplied dialog box procedure. This is because _CPSUICALLBACK-typed callbacks are called from CPSUI's dialog box procedures, which are not used if the application supplies its own procedures.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Desktop |
| Header | compstui.h (include Compstui.h) |