typedef struct {
    UINT cbSize;
    LPSTR szClass;
    WORD wEnableMsg;
} ENABLECLASS_PARAMS;
DIF_ENABLECLASS class install parameters
cbSize
Size of the ENABLECLASS_PARAMS struct.
szClass
The class that is being enabled.
wEnableMsg
Specifies the stage of enabling. Can be one of:
| ENABLECLASS_QUERY | The class is about to be enabled. Return ERR_DI_DO_DEFAULT to allow the class to be enabled, or ERR_DI_FAIL_QUERY to prevent the class from being enabled. | 
| ENABLECLASS_SUCCESS | The enabling of the class has succeeded, return ERR_DI_DO_DEFAULT. | 
| ENABLECLASS_FAILURE | The enabling of the class has failed, return ERR_DI_DO_DEFAULT. |