相同的号码一直在被生成

Question

当我每次尝试生成一个新的随机int来填充数组时，它只会给出相同的数字。种子不会变的。我相信有一个简单的答案，但我已经看了几个小时，只是看不到它。

internal class LingoCard  :  ILingoCard
    {
        private ICardNumber[,] _cardNumber;
        private int _teller;
        private int _oddTeller;
        private int rand;
        Random rnd = new Random();
        public LingoCard(bool useEvenNumbers)
        {

            ICardNumber[,] cardNumber = new ICardNumber[5,5];
            _cardNumber = cardNumber;
            if (useEvenNumbers == true)
            {
                UseEvenNumbers(_cardNumber);
            } else {
                UseOddNumbers(_cardNumber);
            }
          
        }
        

        public void UseEvenNumbers(ICardNumber[,] cardNumber)
        {
            while (_teller < 70)
            {
                for (int g = 0; g < 1; g++)
                {
                    rand = rnd.Next(0, 70);
                    CardNumber _walue = new CardNumber(rand);
                    if (rand % 2 == 0)
                    {
                        for (int i = 0; i < cardNumber.GetLength(0); i++)
                        {
                            for (int j = 0; j < cardNumber.GetLength(1); j++)
                            {
                                _cardNumber[i, j] = _walue;
                            }
                            _teller++;
                        }
                    }
                }
            }
        }

Answer 1

所有卡号的随机数相同的原因是，在两个嵌套的for循环之前生成一个随机数，并使用它来填充每个卡号。

rand = rnd.Next(0, 70); // Random number generated once here
                    CardNumber _walue = new CardNumber(rand);
                    if (rand % 2 == 0)
                    {
                        for (int i = 0; i < cardNumber.GetLength(0); i++)
                        {
                            for (int j = 0; j < cardNumber.GetLength(1); j++)
                            {
                                _cardNumber[i, j] = _walue; // same random value assigned for every card number here
                            }
                            _teller++;
                        }
                    }

为了修复它，在分配_cardNumber时，需要在for循环中生成随机数。

for (int i = 0; i < cardNumber.GetLength(0); i++)
                    {
                        for (int j = 0; j < cardNumber.GetLength(1); j++)
                        {
                            rand = rnd.Next(0, 70) * 2; // Multiply by 2 so the random number is even
                            CardNumber _walue = new CardNumber(rand);
                            _cardNumber[i, j] = _walue;
                        }

                        _teller++;
                    }

如果这有帮助的话请告诉我！