Foreach，对象引用未设置为对象的实例c＃

Question

我想创建所有单独的食物对象，这些对象已被玩家拾取但不知何故我不断收到错误;对象引用未设置为对象的实例。

int indexFood;

public Sprite(Graphics paper)
{
    while (indexFood < 50)
    {
        foodArray[indexFood] = new Food();
        indexFood++;
    }
}

public void DrawFood(Graphics drawArea)
{
    foreach (Food food in foodArray)
    {
        food.DrawFood(drawArea);
        food.XPos = 8;
        food.XPos += 32;
    }
}

这是foodClass方法代码：

public void DrawFood(Graphics drawArea)
{
    drawArea.FillEllipse(new SolidBrush(Color.Yellow), xPosFood, yPosFood, size, size);
}