C＃嵌套对象属性

Question

Hello I am doing some tests in C# with nesting properties which return objects, but I am getting an object reference exception.

I want to be able to access the arrays in nested Properties, but in the current context I can see that I'm not instancing any new objects inside the properties.

This is where the basic question comes up... Where do I declare a 'new' object instance in the middle of all this? Do I even need to declare and new object reference inside the 'foo' class or 'bar' class?

namespace CustomProperties_TEST
{
    class Program
    {
        public foo[] Blatherskite { get; set; }

        static void Main(string[] args)
        {
            Program myProgram = new Program();

            myProgram.Blatherskite[0].CustomProperty1[0].CustomProperty2 = 999999999;
            myProgram.Blatherskite[1].CustomProperty1[0].CustomProperty2 = 999999999;

            foreach (var item in myProgram.Blatherskite)
            {
                Console.WriteLine(item.CustomProperty1[0].CustomProperty2);
            }
        }
    }

    class foo
    {
        private bar[] customevariable1;

        public bar[] CustomProperty1
        {
            get { return customevariable1; }
            set { customevariable1 = value; }
        }
    }

    class bar
    {
        private int customintvariable2;

        public int CustomProperty2
        {
            get { return customintvariable2; }
            set { customintvariable2 = value; }
        }
    }
}

Answer 1

You would want to do something like the following, since arrays are initialized to null by default.

static void Main(string[] args)
{
    Program myProgram = new Program();

    // This is your missing initialization
    myProgram.Blatherskite = new foo[2] {
          new foo{CustomProperty1 = new bar[2]{new bar{CustomProperty2 = 1},new bar{CustomProperty2 = 2}}}
        , new foo{CustomProperty1 = new bar[2]{new bar{CustomProperty2 = 3},new bar{CustomProperty2 = 4}}}};

    myProgram.Blatherskite[0].CustomProperty1[0].CustomProperty2 = 999999999;
    myProgram.Blatherskite[1].CustomProperty1[0].CustomProperty2 = 999999999;

    foreach (var item in myProgram.Blatherskite)
    {
        Console.WriteLine(item.CustomProperty1[0].CustomProperty2);
    }
}

Using arrays means you'll have to set their size. If you would want more flexibility, use a List , and then you can simply add items to it.