I searched around on Google for this, but the only things I came up with were outdated and did not work.
Does anyone have any information on how to get joystick data
Google led me here and while not a requirement of this question, OpenTK is a good option for Windows and Linux (under mono) support.
From the OpenTK docs, this code works on Raspberry Pi + Raspbian + Mono 3.12.0:
for (int i = 0; i < 4; i++)
{
var state = Joystick.GetState(i);
if (state.IsConnected)
{
float x = state.GetAxis(JoystickAxis.Axis0);
float y = state.GetAxis(JoystickAxis.Axis1);
// Print the current state of the joystick
Console.WriteLine(state);
}
}