C# 错误 : Use of unassigned local variable

Question

错误是在for循环中引起的:

for (i = 0; i < hand.Length; i++)
{
   Console.WriteLine(hand[i]);
}

我正在尝试存储这些值以便以后能够显示它们。 writeline 可以帮助我确保代码确实按照我的预期运行。

其余代码供引用:*编辑:添加了一行代码

enum house //variable type for the card type
{
    Spades, Hearts, Clubs, Diamonds
}

enum cards //variable type for the cards
{
    Joker, Ace, Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten, Jack, Queen, King
}

class Program
{
    static void Main(string[] args)
    {

        Random rnd;
        Random rnd2;

        int i;
        int random;
        int random2;

        String[] hand;

        house randomhouse;
        cards randomcard;

        //all declared variables

        Console.WriteLine("Your hand is made up of :");

        for (i = 0; i <= 6; i++)//does everything in the {} until i is equal to 6
        {

            rnd2 = new Random();
            random2 = rnd2.Next(0, 14);
            randomcard = (cards)random2; //selecting a random card from joker to king

            if (randomcard > (int)cards.Joker) //if the random card isn't a joker
            {
                rnd = new Random();
                random = rnd.Next(0, 4);
                randomhouse = (house)random;//selects a random card type

                Console.WriteLine(randomcard + " of " + randomhouse); //outputs the name of the card
                System.Threading.Thread.Sleep(1000);//wait 1 second before getting the new card
            }

            else
            {
                Console.WriteLine(randomcard);//outputs "Joker"
                System.Threading.Thread.Sleep(1000);//wait 1 second before getting the new card
            }

            hand = new String[i];//making a new array value for every loop
            hand[i] = randomcard.ToString();//adding randomcard to the array*

        } 

        Console.Clear();

        for (i = 0; i < hand.Length; i++)
        {
            Console.WriteLine(hand[i]);
        }

        Console.ReadKey();
    }
}

Answer 1

编译器永远无法确定 hand 是否已实际初始化。您应该提前初始化它，或者将其设置为 null，这样您就可以绕过此编译器检查。

所以你可以这样做，但实际上这是不好的做法!更改代码时，您可能会遇到 NullReferenceException!

String[] hand = null;

您确实知道您的代码实际上不起作用，因为您最终得到的是一个数组。我想你的意思是:

hand = new String[6];

...

hand[i] = theValue;