画给我一个对象处置异常

下面的代码给了我一个ObjectDisposedException。我在内容加载器中加载内容就好了。它不时工作，但偶尔会引发异常。

所有纹理都完美加载，每个对象都有正确的纹理并且实际存在。没有任何地方可以卸载内容。

错误在最后一个 spriteBatch.End（） 处抛出;

出了什么问题？

 protected override void Draw(GameTime gameTime)
        {
            if (startMenu.showMenu)
            {
                spriteBatch.Begin();
                startMenu.Draw(spriteBatch);
                spriteBatch.End();
            }
        if (selectedLevel != null && !startMenu.showMenu)
        {
            spriteBatch.Begin(SpriteSortMode.Deferred, null, null, null, null, null,
            selectedLevel.GetCamera().getViewMatrix(new Vector2(1.0f)));
            for (int layer_inc = 0; layer_inc <= selectedLevel.layers.Count() - 1; layer_inc++)
            {
                selectedLevel.layers[layer_inc].Draw(gameTime, spriteBatch);
            }
            if (selectedLevel.GetPlayer().IsAlive())
            {
                Weapon weapon = selectedLevel.GetPlayer().GetWeapon();
                weapon.Draw(gameTime, spriteBatch);
                if (selectedLevel.GetPlayer().isMeditating())
                {
                    Player player = selectedLevel.GetPlayer();
                    MeditationBoost meditationBoost = ((MeditationBoost)player.getBoost());
                    meditationBoost.Draw(spriteBatch, player.position);
                }
                if (weapon is ShootableWeapon)
                {
                    ShootableWeapon shootableWeapon = (ShootableWeapon)weapon;
                    if (shootableWeapon.getAmmo().Count() > 0)
                    {
                        for (int ammo_inc = 0; ammo_inc <= shootableWeapon.getAmmo().Count() - 1; ammo_inc++)
                        {
                            shootableWeapon.getAmmo()[ammo_inc].Draw(gameTime, spriteBatch);
                        }
                    }
                }
            }
            foreach (MovableObject movableObject in selectedLevel.movableObjects)
            {
                if (movableObject is Enemy)
                {
                    Enemy enemy = (Enemy)movableObject;
                    ThrowAttack attack = ((ThrowAttack)enemy.getAttack());
                    if (attack != null && attack.getThrowObject() != null)
                    {
                        attack.getThrowObject().Walk(Direction.Right, attack.getThrowObject().speed);
                        attack.getThrowObject().Update(gameTime);
                        attack.getThrowObject().Draw(spriteBatch);
                    }
                }
            }
            updateScreenText(spriteBatch);
            try
            {
                spriteBatch.End();
            }
            catch (ObjectDisposedException e)
                {
                    Debug.Write(e);
                }
        }
        base.Draw(gameTime);
    }

编辑：

这就是我动态加载内容的方式（使用此功能时，我将文件夹作为字符串给出）

    public void Loadlistontent(string contentFolder)
    {
        DirectoryInfo dir = new DirectoryInfo(Content.RootDirectory + "/" + contentFolder);
        if (!dir.Exists)
            throw new DirectoryNotFoundException();
        FileInfo[] files = dir.GetFiles("*.*");
        foreach (FileInfo file in files)
        {
            if (!textureLoader.GetTextures().ContainsKey(file.Name))
            {
                string key = Path.GetFileNameWithoutExtension(file.Name);

                Texture2D texture = Content.Load<Texture2D>(contentFolder + "/" + key);
                textureLoader.addTexture(file.Name, texture);
            }
        }
    }