数组中对象内的C＃数组

Question

以下是我的代码的简化版本：

   class House
{
    private string owner;
    private int[] roomArea = new int[10];

    public string Owner { get; set; }
    public int[] RoomArea { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
        House[] london = new House[100];
        for (int i = 0; i < 100; i++)
        {
            london[i] = new House();
        }

        london[0].Owner = "Timmy";
        london[0].RoomArea[0] = 15; // Error points to this line

        Console.WriteLine("Room 1 in " + london[0].Owner + "s house has the area of " + london[0].RoomArea[0] + "square meters");


    }
}

我收到以下错误：

 Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object.

我看过这个this question/solution，但我无法确定代码的确切错误。

Answer 1

您需要初始化 RoomArea 。即使你在类中初始化它正在创建它自己的成员，但是为了添加你需要初始化它的值

london[0].RoomArea  = new int[10];
london[0].RoomArea[0] = 15;