XBOX360 偵測按鈕

XNA有提供GamePadState類別可以偵測觸發了哪個按鈕，XBOX360可以在同時間偵測4個手把的動作
要取得第一個把手觸發的按鈕，可以宣告一個GamePadState類別，並且透過GamePad的GetState去取得狀態

GamePad的GetState的方法可以帶入指定的手把編號，手把編號可以透過PlayerIndex列舉去指定

GamePadState gamePadState = GamePad.GetState(PlayerIndex.One);

當第一個手把按下手把上的按鈕，就會將程式標題改成按鈕名稱

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;

namespace WindowsGame1
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        private GraphicsDeviceManager graphics;
        private SpriteBatch spriteBatch;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            // TODO: Add your initialization logic here

            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            // TODO: use this.Content to load your game content here
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();
            GamePadState gamePadState = GamePad.GetState(PlayerIndex.One);

            //開始鈕
            if (gamePadState.Buttons.Start == ButtonState.Pressed)
            {
                this.Window.Title = "Start";
            }

            //A
            if (gamePadState.Buttons.A == ButtonState.Pressed)
            {
                this.Window.Title = "A";
            }

            //B
            if (gamePadState.Buttons.B == ButtonState.Pressed)
            {
                this.Window.Title = "B";
            }

            //X
            if (gamePadState.Buttons.X == ButtonState.Pressed)
            {
                this.Window.Title = "X";
            }

            //Y
            if (gamePadState.Buttons.Y == ButtonState.Pressed)
            {
                this.Window.Title = "Y";
            }

            //LB
            if (gamePadState.Buttons.LeftShoulder == ButtonState.Pressed)
            {
                this.Window.Title = "LeftShoulder";
            }

            //LF
            if (gamePadState.Buttons.RightShoulder == ButtonState.Pressed)
            {
                this.Window.Title = "RightShoulder";
            }

            //左搖桿
            if (gamePadState.Buttons.LeftStick == ButtonState.Pressed)
            {
                this.Window.Title = "LeftStick";
            }

            //右搖桿
            if (gamePadState.Buttons.RightStick == ButtonState.Pressed)
            {
                this.Window.Title = "RightStick";
            }

            //十字鍵 下
            if (gamePadState.DPad.Down == ButtonState.Pressed)
            {
                this.Window.Title = "Down";
            }

            //十字鍵 上
            if (gamePadState.DPad.Up == ButtonState.Pressed)
            {
                this.Window.Title = "Up";
            }

            //十字鍵 左
            if (gamePadState.DPad.Left == ButtonState.Pressed)
            {
                this.Window.Title = "Left";
            }

            //十字鍵 右
            if (gamePadState.DPad.Right == ButtonState.Pressed)
            {
                this.Window.Title = "Right";
            }

            // TODO: Add your update logic here

            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            // TODO: Add your drawing code here

            base.Draw(gameTime);
        }
    }
}

參考資料：
http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.input.gamepadstate.aspx
http://msdn.microsoft.com/en-us/library/bb203900.aspx
http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.input.gamepadstate_members.aspx