Question

int PlayerAmount = 10;
int CurrentPlayer = 0;
Player[] player = new Player[PlayerAmount];

while (true)
{
    string Input;
    Console.WriteLine("What would you like to do?");
    Console.WriteLine("1. Create new player and score.");
    Console.WriteLine("2. Display Highscores.");
    Console.WriteLine("3. Write out to XML file.");
    Console.Write("Input Number: ");
    Input = Console.ReadLine();
    if (Input == "1")
    {
        if (CurrentPlayer >= PlayerAmount)
        {
            Console.WriteLine();
            Console.WriteLine("MAX AMOUNT OF PLAYERS HAS BEEN REACHED!");
            Console.WriteLine();
        }
        else
        {
            string PlayerName;
            string Score;

            Console.WriteLine();
            Console.WriteLine("-=CREATE NEW PLAYER=-");
            Console.Write("Player name: ");
            PlayerName = Console.ReadLine();
            Console.Write("Player score: ");
            Score = Console.ReadLine();

            //=========================================
            //THIS IS WHERE THE ERROR OCCURS===========
            //=========================================
            player[CurrentPlayer].Name = PlayerName;


            Console.WriteLine("Player \"" + player[CurrentPlayer].Name + "\" with the score of \"" + player[CurrentPlayer].Score + "\" has been created successfully!" );
            Console.WriteLine();
        }
    }
    else if (Input == "2")
    {
        Console.WriteLine("Displaying the highscores");
    }
    else if (Input == "3")
    {
        Console.WriteLine("Writing to XML file");
    }
    else
    {
        Console.WriteLine("INVALID INPUT");
    }
}

我已经尝试过使用字符串副本，但这只是给了我同样的错误，我已经在代码中指出了问题，但是如果你看不到它正在复制播放器名称的位置： “player [CurrentPlayer] .Name = PlayerName;”

提前致谢

Answer 1

在我看来：

player[CurrentPlayer].Name

为空。确保索引currentPlayer处的播放器对象不为空。

初始化数组时，默认情况下所有对象都为空（非基元）。所以你必须在数组中为每个索引实例化每个玩家。

这一行：

Player[] player = new Player[PlayerAmount];

仅分配一个大小为playerAmount的数组（在您的情况下为10）;

你需要这个来初始化它们：

for(int i =0; i < player.length;i++)  
{  
     player[i] = new Player();
}

Answer 2

您没有初始化Player数组的每个成员。做完之后：

Player[] player = new Player[PlayerAmount];

您可能也希望这样做：

for (int i = 0; i < PlayerAmount; i++)
{
    Player[i] = new Player();
}

因为事先，数组只包含一堆null引用。

Answer 3

你也可以像

一样做懒惰的事情

player[CurrentPlayer] = new Player();
player[CurrentPlayer].Name = PlayerName;

继续获取“对象引用未设置为对象的实例”。复制字符串时

3 个答案: