Joystick acquisition with SharpDX

Question

I'm new about C# and Sharpdx. I have this code problem from a couple of days and I don't understand way doesn't work! This is a simple task about acquiring a value of one axis of a Joystick and show it on a text box in a Form.

I did a new project on Visual Studio 2010 express and I did a Form with a button and a textBox for show the value of the joystick axis (X axis).

The first part of code down here is the example on the sharpdx documentation, the second part is a little bit different.

The problem is that the value doesn't change every time I push the button

Something is wrong but I don't know what

private void button3_Click(object sender, EventArgs e)
{
  // Initialize DirectInput
  var directInput = new DirectInput();

  // Find a Joystick Guid
  var joystickGuid = Guid.Empty;

  foreach (var deviceInstance in directInput.GetDevices(DeviceType.Gamepad,  DeviceEnumerationFlags.AllDevices))
    joystickGuid = deviceInstance.InstanceGuid;

  // If Gamepad not found, look for a Joystick
  if (joystickGuid == Guid.Empty)
    foreach (var deviceInstance in directInput.GetDevices(DeviceType.Joystick,  DeviceEnumerationFlags.AllDevices))
      joystickGuid = deviceInstance.InstanceGuid;

  // If Joystick not found, throws an error
  if (joystickGuid == Guid.Empty)
  {
      Console.WriteLine("No joystick/Gamepad found.");
      Console.ReadKey();
      Environment.Exit(1);
  }  

  // Instantiate the joystick e stato
  Joystick joystick = new Joystick(directInput, joystickGuid);
  JoystickState stato = new JoystickState();

  // specifico se relativo o assoluto
  joystick.Properties.AxisMode = DeviceAxisMode.Absolute;

  // effettuo un collegamento con il joystick
  joystick.Acquire();

  // qui faccio una acquisizione dello stato che memorizzo
  joystick.Poll();

  // effettuo una lettura dello stato
  joystick.GetCurrentState(ref stato);

  // stampo il valore dell'ordinata
  textBox1.Text = stato.X.ToString();
}

Answer 1

I think the problem is that you are calling both Poll and GetCurrentState - you only need do one or the other.

From your question it sounds like the latter - that is you want to GetCurrentState when the button is pressed - not Poll for changes in a loop.

If you do want to get the current state then you want something like this.

var directInput = new DirectInput();
var joystickState = new JoystickState();
var joystick = new Joystick(directInput, joystickGuid);
joystick.Acquire();
joystick.GetCurrentState(ref joystickState);
textBox1.Text = joystickState.X.ToString();

If you want to poll for changes you you want something like this.

var directInput = new DirectInput();
var joystick = new Joystick(directInput, joystickGuid);
joystick.Acquire();
joystick.Properties.BufferSize = 128;
while (true)
{
  joystick.Poll();
  var data = joystick.GetBufferedData();
  foreach (var state in data) 
  {
    if (state.Offset == JoystickOffset.X)
    {
       textBox1.Text = state.Value;
    }
  }
}