C＃ArgumentNullException未處理（SpriteBatch.Draw）

Question

我實際上是XNA的一名新生，發現這個庫非常有趣，但我仍然缺乏一些知識，因為我覺得在一個問題上我無法自行修復:(

spriteBatch.Draw（）方法說我的紋理為null，但是我已將它加載到Resources.cs類中並在MainMenu.cs中傳遞紋理，所以我真的不知道問題所在的位置，如果有人可以幫我的話關於我，我會非常感激！

Resources.cs

    class Resources
{
    public static Texture2D pixel;
    public static Texture2D startButton, loadButton, quitButton;

    public static SpriteFont consoleFont;

    public static void LoadContent(ContentManager Content)
    {
        pixel = Content.Load<Texture2D>("Pixel");
        consoleFont = Content.Load<SpriteFont>("Console");

        // UI Ressources :
        startButton = Content.Load<Texture2D>("UI/StartButton");
        loadButton = Content.Load<Texture2D>("UI/LoadButton");
        quitButton = Content.Load<Texture2D>("UI/QuitButton");
    }
}

MainMenu.cs

    class MainMenu
{
    // Fields
    List<Button> buttons = new List<Button>();

    // Constructors
    public MainMenu()
    {
        this.buttons.Add(new Button(new Vector2(480, 132), 256, 48, Resources.startButton));
        this.buttons.Add(new Button(new Vector2(480, 212), 256, 48, Resources.loadButton));
        this.buttons.Add(new Button(new Vector2(480, 292), 256, 48, Resources.quitButton));
    }

    // Methods

    // Update
    public void Update()
    {
    }

    // Draw
    public void Draw(SpriteBatch spriteBatch)
    {
        foreach (Button button in buttons)
        {
            button.Draw(spriteBatch);
        }
    }
}

Button.cs

    class Button : UIElement
{
    int width, height;
    Texture2D texture;

    public Button()
    {
    }

    public Button(Vector2 b_position, int b_width, int b_height, Texture2D b_texture)
    {
        this.position = b_position;
        this.width = b_width;
        this.height = b_height;
        this.texture = b_texture;
    }

    public void Update()
    {
    }

    public void Draw(SpriteBatch spriteBatch)
    {
        spriteBatch.Draw(texture, position, Color.White);
    }
}

Answer 1

雖然我沒有看到您的Game類，但我的第一個假設是您從未在Resources類中調用public static void LoadContent（ContentManager Content）方法。 由於此函數正在實例化您的紋理，因此可能不會調用它。

Answer 2

謝謝您的回復 ！ 確實我忘了包含Game類，這是調用資源的正確方法嗎？

    public class GameMain : Microsoft.Xna.Framework.Game
{
    GraphicsDeviceManager graphics;
    SpriteBatch spriteBatch;

    MainMenu mainMenu;

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

        this.IsMouseVisible = true;

        mainMenu = new MainMenu();
    }

    protected override void Initialize()
    {
        // TODO: Add your initialization logic here

        base.Initialize();
    }

    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
        Resources.LoadContent(Content);
    }

    protected override void UnloadContent()
    {
        // TODO: Unload any non ContentManager content here
    }

    protected override void Update(GameTime gameTime)
    {
        // Allows the game to exit
        if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            this.Exit();

        // TODO: Add your update logic here
        base.Update(gameTime);
    }

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

        // TODO: Add your drawing code here
        spriteBatch.Begin();
        mainMenu.Draw(spriteBatch);
        spriteBatch.End();
        base.Draw(gameTime);
    }
}

Answer 3

簡單的真實
你只需要知道Game1函數的調用順序。 首先，調用Game1構造函數。 這就是你把mainMenu = new MainMenu(); 。 之后再進行Initialize ， Load等操作。 你必須移動mainMenu = new MainMenu(); 從Game1構造函數到Load函數，在Resources.LoadContent(Content); ，因此可以在MainMenu中使用之前加載資源。 你的Game1.cs代碼應如下所示：

public class GameMain : Microsoft.Xna.Framework.Game
{
    GraphicsDeviceManager graphics;
    SpriteBatch spriteBatch;

    MainMenu mainMenu;

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

        this.IsMouseVisible = true;
    }

    protected override void Initialize()
    {
        // TODO: Add your initialization logic here

        base.Initialize();
    }

    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
        Resources.LoadContent(Content);
        mainMenu = new MainMenu();
    }

    protected override void UnloadContent()
    {
        // TODO: Unload any non ContentManager content here
    }

    protected override void Update(GameTime gameTime)
    {
        // Allows the game to exit
        if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            this.Exit();

        // TODO: Add your update logic here
        base.Update(gameTime);
    }

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

        // TODO: Add your drawing code here
        spriteBatch.Begin();
        mainMenu.Draw(spriteBatch);
        spriteBatch.End();
        base.Draw(gameTime);
    }
}