C# で XInput おためし、おきらく (取得はともかく振動はテストしてないです)

XInput.cs

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Security;

namespace Linearstar.Lavis.Interop
{
	public class XInput
	{
		const string XInputLibrary = "XINPUT9_1_0";

		#region P/Invoke

		[SuppressUnmanagedCodeSecurity, DllImport(XInputLibrary)]
		static extern int XInputGetCapabilities(int dwUserIndex, int dwFlags, out XInputCapabilities pCapabilities);
		[SuppressUnmanagedCodeSecurity, DllImport(XInputLibrary)]
		static extern int XInputGetState(int dwUserIndex, out XInputState pState);
		[SuppressUnmanagedCodeSecurity, DllImport(XInputLibrary)]
		static extern int XInputSetState(int dwUserIndex, ref XInputVibration pVibration);

		const int ERROR_SUCCESS = 0;
		const int ERROR_DEVICE_NOT_CONNECTED = 1167;

		struct XInputCapabilities
		{
			public byte Type;
			public XInputDeviceSubType SubType;
			public XInputDeviceCapabilityFlags Flags;
			public XInputGamepad Gamepad;
			public XInputVibration Vibration;
		}

		struct XInputGamepad
		{
			public XInputButtons Buttons;
			public byte LeftTrigger;
			public byte RightTrigger;
			public short ThumbLX;
			public short ThumbLY;
			public short ThumbRX;
			public short ThumbRY;
		}

		struct XInputVibration
		{
			public ushort LeftMotorSpeed;
			public ushort RightMotorSpeed;
		}

		struct XInputState
		{
			public int dwPacketNumber;
			public XInputGamepad Gamepad;
		}

		#endregion

		static void EnsureErrorState(int errorState)
		{
			if (errorState == ERROR_SUCCESS)
				return;
			else if (errorState == ERROR_DEVICE_NOT_CONNECTED)
				throw new InvalidOperationException();
			else
				throw new Win32Exception(errorState);
		}

		readonly XInputCapabilities capabilities;
		XInputState state;
		XInputState previousState;

		public int PlayerIndex
		{
			get;
		}

		public XInputDeviceSubType Kind => capabilities.SubType;
		public XInputDeviceCapabilityFlags Capabilities => capabilities.Flags;
		public XInputButtons Buttons => state.Gamepad.Buttons;
		public double LeftStickX =>
			state.Gamepad.ThumbLX > 0 ? state.Gamepad.ThumbLX / (double)short.MaxValue : -state.Gamepad.ThumbLX / (double)short.MinValue;
		public double LeftStickY =>
			state.Gamepad.ThumbLY > 0 ? -state.Gamepad.ThumbLY / (double)short.MaxValue : state.Gamepad.ThumbLY / (double)short.MinValue;
		public double RightStickX =>
			state.Gamepad.ThumbRX > 0 ? state.Gamepad.ThumbRX / (double)short.MaxValue : -state.Gamepad.ThumbRX / (double)short.MinValue;
		public double RightStickY =>
			state.Gamepad.ThumbRY > 0 ? -state.Gamepad.ThumbRY / (double)short.MaxValue : state.Gamepad.ThumbRY / (double)short.MinValue;
		public double LeftTrigger => state.Gamepad.LeftTrigger / 255.0;
		public double RightTrigger => state.Gamepad.RightTrigger / 255.0;

		public XInput(int playerIndex)
		{
			if (playerIndex < 0 || playerIndex >= 4)
				throw new ArgumentException($"{nameof(playerIndex)} must be 0, 1, 2, or 3.", nameof(playerIndex));

			this.PlayerIndex = playerIndex;

			EnsureErrorState(XInputGetCapabilities(this.PlayerIndex, 0, out capabilities));
		}

		public void Update()
		{
			previousState = state;
			EnsureErrorState(XInputGetState(this.PlayerIndex, out state));
		}

		public bool IsDown(XInputButtons button) => (state.Gamepad.Buttons & button) != 0;
		public bool IsPress(XInputButtons button) => (state.Gamepad.Buttons & button) != 0 && (previousState.Gamepad.Buttons & button) == 0;
		public bool IsRelease(XInputButtons button) => (state.Gamepad.Buttons & button) == 0 && (previousState.Gamepad.Buttons & button) != 0;

		public void SetVibration(double leftMotorSpeed, double rightMotorSpeed)
		{
			var vib = new XInputVibration
			{
				LeftMotorSpeed = (ushort)(ushort.MaxValue * leftMotorSpeed),
				RightMotorSpeed = (ushort)(ushort.MaxValue * rightMotorSpeed),
			};

			XInputSetState(this.PlayerIndex, ref vib);
		}
	}

	public enum XInputDeviceSubType : byte
	{
		Unknown,
		Gamepad,
		Wheel,
		ArcadeStick,
		FlightStick,
		DancePad,
		Guitar,
		GuitarAlternate,
		DrumKit,
		GuitarBass = 11,
		ArcadePad = 19,
	}

	public enum XInputDeviceCapabilityFlags : ushort
	{
		None,
		ForceFeedbackSupported = 1,
		Wireless = 1 << 1,
		VoiceSupported = 1 << 2,
		PluginModulesSupported = 1 << 3,
		NoNavigation = 1 << 4,
	}

	public enum XInputButtons : ushort
	{
		None,
		DPadUp = 0x0001,
		DPadDown = 0x0002,
		DPadLeft = 0x0004,
		DPadRight = 0x0008,
		Start = 0x0010,
		Back = 0x0020,
		LeftThumb = 0x0040,
		RightThumb = 0x0080,
		LeftShoulder = 0x0100,
		RightShoulder = 0x0200,
		A = 0x1000,
		B = 0x2000,
		X = 0x4000,
		Y = 0x8000,
	}
}