c# - 我在 XNA 的第一个游戏(小问题)

Question

到目前为止，这是我的代码:Game1.cs 类:

 public class Game1 : Microsoft.Xna.Framework.Game
{
    GraphicsDeviceManager graphics;
    SpriteBatch spriteBatch;
    Player MyPlayer;
    Texture2D Ball;
    int GraphicsWidth,GraphicsHeight;
    public Game1()
    {
        graphics = new GraphicsDeviceManager(this);
        Content.RootDirectory = "Content";
    }

    protected override void Initialize()
    {
        GraphicsWidth = graphics.PreferredBackBufferWidth;
        GraphicsHeight= graphics.PreferredBackBufferHeight;
        MyPlayer = new Player(Ball, new Vector2(100, 100), Vector2.Zero);
        base.Initialize();
    }

    protected override void LoadContent()
    {
        spriteBatch = new SpriteBatch(GraphicsDevice);
        Ball = Content.Load<Texture2D>("Images/ball");

    }

    protected override void UnloadContent()
    {
    }

    protected override void Update(GameTime gameTime)
    {
        if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            this.Exit();


        base.Update(gameTime);
    }

    protected override void Draw(GameTime gameTime)
    {
        GraphicsDevice.Clear(Color.CornflowerBlue);

        MyPlayer.Draw(spriteBatch);

        base.Draw(gameTime);
    }
}

球员类(球):

class Player
{
    Texture2D Texture;
    Vector2 Positon,Velocity;
    public int Height
    {
        get { return this.Texture.Height; }
    }
    public int Width
    {
        get { return this.Texture.Width; }
    }


    public Player(Texture2D tex, Vector2 position,Vector2 velocity)
    {
        this.Texture = tex;
        this.Positon = position;
        this.Velocity = velocity;
    }
    public void Draw(SpriteBatch spriteBatch)
    {
       spriteBatch.Begin();
       spriteBatch.Draw(Texture, Positon, Color.White);
       spriteBatch.End();
    }
}

当我尝试调试游戏时出现以下错误:

此方法不接受此参数为 null。参数名称:纹理在那个部分:

public void Draw(SpriteBatch spriteBatch)
    {
       spriteBatch.Begin();
       spriteBatch.Draw(Texture, Positon, Color.White);
       spriteBatch.End();
    }

顺便说一句，我想问一下我是否可以改进这段代码或类似的东西。非常感谢!

Answer 1

看起来您在加载 Ball 内容之前创建了 Player 对象，因此，播放器持有 null 而不是纹理，但是 Ball 字段在游戏才是真正的质感。

在您分配了 Ball 之后，我会将 Player 的创建移动到 LoadContent 中。

Ball = Content.Load<Texture2D>("Images/ball");
MyPlayer = new Player(Ball, new Vector2(100, 100), Vector2.Zero);