XNA Texture2D列表outOfRangeException

Question

首先，我是xna的新手。尝试抓取21点游戏。我已经创建了2个列表来添加随机卡到列表中。但是我不明白为什么不把图片添加到列表tekstuur2中

代码如下：

public class Kaart
    {

        public Vector2 asukoht = new Vector2(0, 0);

        public List<Texture2D> tekstuur = new List<Texture2D>();
        public List<Texture2D> tekstuur2 = new List<Texture2D>();

        Random  rand = new Random();
        public void loadContent2(ContentManager manager2)
        {



            for (int x = 3; x < 7; x++)

                tekstuur2.Add(manager2.Load<Texture2D>("Risti" + x.ToString()));

        }

        public void loadContent(ContentManager manager)
        {

            for (int j = 3; j < 7; j++)



                tekstuur.Add(manager.Load<Texture2D>("Risti" + j.ToString()));

        }

        public void Draw(SpriteBatch sprite)
        {

            sprite.Draw(tekstuur[rand.Next(tekstuur.Count)], asukoht, Color.White);
            sprite.Draw(tekstuur2[rand.Next(tekstuur2.Count)], asukoht, Color.White); 
// an error occurs (ArgumentOutofRangeException) , tekstuur2.count = 0 at that point, but at the tekstuur.Count it is 4.

        }

    }
}

下面是另一个调用这些方法的类：

namespace WindowsGame1
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
    GraphicsDeviceManager graphics;
    SpriteBatch spriteBatch;
    Vector2 koht = new Vector2(0,0);

    Kaart yks;
    Kaart kaks;


    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
        yks = new Kaart();
        kaks = new Kaart();

        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);

        //kaardi laadimine 
        yks.loadContent(this.Content);
        kaks.loadContent2(this.Content);


        // yhe kaarti asukoht
        yks.asukoht.X = 100;
        yks.asukoht.Y = 300;
        // teise kaardi asukoht
        kaks.asukoht.X = 200;
        kaks.asukoht.Y = 400;



        // 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();



        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)
    {
        // kaartide joonistamine 
        GraphicsDevice.Clear(Color.CornflowerBlue);
        spriteBatch.Begin();
        yks.Draw(this.spriteBatch);
        kaks.Draw(this.spriteBatch);

        spriteBatch.End();

        // TODO: Add your drawing code here

        base.Draw(gameTime);
    }
}

}

Answer 1

好的，问题是你应该为Kaart的每个实例(在你的例子中是yks和kaks)调用loadContent，并在你的方法LoadContent中调用loadContent2：

    //kaardi laadimine 
    yks.loadContent(this.Content);
    kaks.loadContent2(this.Content);

成为：

    //kaardi laadimine 
    yks.loadContent(this.Content);
    yks.loadContent2(this.Content);
    kaks.loadContent2(this.Content);
    kaks.loadContent(this.Content);

请注意，由于纹理是相同的，因此不需要使用两个不同的列表来包含它们，您可以在Kaart Draw方法中执行此操作：

sprite.Draw(tekstuur[rand.Next(tekstuur.Count)], asukoht, Color.White);
sprite.Draw(tekstuur[rand.Next(tekstuur.Count)], asukoht, Color.White); 

这样，您只需调用LoadContent。

另一个注意事项:目前您正在实例化一个随机数；问题是不推荐连续实例化这个类(在短时间内)，并且您的两个KArt将使用相同的随机纹理。要解决此问题，请将Random rand设置为静态变量：

private static Random  rand = new Random();