The GPIOPullUpDownModeEnum enum defines the pull up or pull down state of a GPIO. Note that the the values here are significant. These are the values we write to the GPPUD to set the pullUpDown state.
public enum GPIOPullUpDownModeEnum
{
PULLUPDOWN_OFF =0x0,
PULLUPDOWN_DOWN =0x1,
PULLUPDOWN_UP =0x2,
}