Sets the data format for the DirectInput device.
HRESULT SetDataFormat( LPCDIDATAFORMAT lpdf );
If the method succeeds, the return value is DI_OK. If the method fails, the return value can be one of the following error values: DIERR_ACQUIRED, DIERR_INVALIDPARAM, DIERR_NOTINITIALIZED.
The data format must be set before the device can be acquired by using the IDirectInputDevice8 Interface method. It is necessary to set the data format only once. The data format cannot be changed while the device is acquired.
If the application is using action mapping, the data format is set instead by the call to IDirectInputDevice8::SetActionMap.
Header: Declared in Dinput.h.