Rectangle只有0个值

Question

我遇到了以下问题：在我的代码中，只打印了一张图片，矩形rectPlayer在Initialize()中有正确的值，但在Draw()的底部所有值都是0.有人可以向我解释原因吗？

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using System;
using System.Collections.Generic;
using System.Linq;

namespace StateMachine
{
    internal class GameLoop
    {
        private Rectangle rectPlayer;
        private int playerPositionX = 800;
        private int playerPositionY = 900;

        protected void Initialize()
        {
            rectPlayer = new Rectangle(playerPositionX, playerPositionY, 40, 65);
        }

        public GameState Update(GameTime gameTime)
        {
            return GameState.GameLoop;
        }

        public void Draw(GameTime gameTime, SpriteBatch spriteBatch, Texture2D playerSprite)
        {
            spriteBatch.Draw(playerSprite, rectPlayer, Color.White);
        }
    }
}

这是调用类：

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
sing System;
using System.Collections.Generic;
using System.Linq;

namespace StateMachine
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class StateMachine : Microsoft.Xna.Framework.Game
{
    public static GraphicsDeviceManager graphics;
    private SpriteBatch spriteBatch;
    private SpriteFont font;
    private GameState currentGameState, previousGameState, targetGameState;
    public Color Background = Color.Black;

    private SplashScreen splashScreen;
    private MainMenu mainMenu;
    private GameLoop gameLoop;
    private Options options;
    private Pause pause;
    private GameOver gameOver;
    private Credits credits;
    private Quit quit;

    private Texture2D playerSprite;
    private Texture2D splashScreenPicture;

    public GameState gameState
    {
        get { return currentGameState; }
    }

    public void ExitCode()
    {
        this.Exit();
    }

    public StateMachine()
    {
        graphics = new GraphicsDeviceManager(this);
        Content.RootDirectory = "Content";
        graphics.IsFullScreen = false;
        graphics.PreferredBackBufferWidth = 1920;
        graphics.PreferredBackBufferHeight = 1080;
        graphics.ApplyChanges();
    }

    protected override void Initialize()
    {
        IsMouseVisible = true;
        currentGameState = GameState.GameLoop;
        base.Initialize();
    }

    protected override void LoadContent()
    {
        spriteBatch = new SpriteBatch(GraphicsDevice);
        splashScreen = new SplashScreen();
        mainMenu = new MainMenu();
        gameLoop = new GameLoop();
        options = new Options();
        pause = new Pause();
        gameOver = new GameOver();
        credits = new Credits();
        quit = new Quit();

        font = Content.Load<SpriteFont>("font");
        playerSprite = Content.Load<Texture2D>("PanzerknackerR1");
        splashScreenPicture = Content.Load<Texture2D>("SplashPic");
    }

    protected override void UnloadContent()
    {
    }

    protected void Input(GameTime gameTime)
    {
        InputManager.Update();
    }

    /// <summary>
    /// Main Update methode. Uses the current Gamestate.Update
    /// </summary>
    /// <param name="gameTime"></param>
    protected override void Update(GameTime gameTime)
    {
        Input(gameTime);

        if (InputManager.GamePadButtonPress(Buttons.Back) || InputManager.KeyPress(Keys.Escape))
            this.Exit();
        switch (currentGameState)
        {
            case GameState.SplashScreen:
                targetGameState = splashScreen.Update(gameTime, Content);
                break;

            case GameState.MainMenu:
                targetGameState = mainMenu.Update(gameTime);
                break;

            case GameState.GameLoop:
                targetGameState = gameLoop.Update(gameTime);
                break;

            case GameState.Options:
                targetGameState = options.Update(gameTime);
                break;

            case GameState.Pause:
                targetGameState = pause.Update(gameTime);
                break;

            case GameState.GameOver:
                targetGameState = gameOver.Update(gameTime);
                break;

            case GameState.Credits:
                targetGameState = credits.Update(gameTime);
                break;

            case GameState.Quit:
                targetGameState = quit.QuitUpdate(gameTime, this);
                break;
        }
        previousGameState = currentGameState;
        currentGameState = targetGameState;

        base.Update(gameTime);
    }

    protected override void Draw(GameTime gameTime)
    {
        spriteBatch.Begin();
        // GraphicsDevice.Clear(Color.Black);
        switch (currentGameState)
        {
            case GameState.SplashScreen:
                splashScreen.Draw(gameTime, spriteBatch, splashScreenPicture);
                break;

            case GameState.MainMenu:
                mainMenu.Draw(gameTime);
                break;

            case GameState.GameLoop:
                gameLoop.Draw(gameTime, spriteBatch, playerSprite);
                break;

            case GameState.Options:
                options.Draw(gameTime);
                break;

            case GameState.Pause:
                pause.Draw(gameTime);
                break;

            case GameState.GameOver:
                gameOver.Draw(gameTime);
                break;

            case GameState.Credits:
                credits.Draw(gameTime);
                break;

            case GameState.Quit:
                quit.QuitDraw(gameTime);
                break;

            default:
                spriteBatch.DrawString(font, "ERROR: GameState", new Vector2(100, 100), Color.White);
                break;
        }

        spriteBatch.End();

        base.Draw(gameTime);
    }
}

}