未知的NullPointerException

Question

海兰!

我想在c#中创建一个cardgame.调试器总是抛出一个NullPointerException.但是var卡不是null(它在调试期间显示了一个值)问题必须在cards.add()中.

我的代码:

namespace Uno_Logic
{
    class CardStack
    {
        private List<Card> cards;
        public void Cardstack()
        {
            cards = new List<Card>();
        }
        public void fillCardstack ()
        {
            for (Card_Value value = Card_Value.One; value <= Card_Value.DrawTwo; value++)
            {
                for (Card_Colour colour = Card_Colour.Yellow; colour < Card_Colour.Black; colour++)
                {
                    Card card = new Card(colour, value);
                    Card card2 = new Card(colour, value);
                    cards.Add(card); //**here throws the debugger the Exception**
                    cards.Add(card2);
                }

            }
         }
      }
   }

请帮忙!

Answer 1

更换:

    public void CardStack()
    {
        cards = new List<Card>();
    }

同

    public CardStack()
    {
        cards = new List<Card>();
    }

c#中的构造函数没有返回类型