C# nested object properties

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; }
        }
    }
}

Noctis · Accepted Answer · 2015-08-03 01:29:46Z

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.

answered Aug 3, 2015 at 1:29

Noctis

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2 Comments

user5183820 Over a year ago

This is awesome. I knew I was missing one of the blocks. But searching for Nested Properties didn't yield much. A newbie question but I hope this helps others like me.Thank you.

Noctis Over a year ago

Glad it helped. If you find it helpful, you can vote and mark as answered. Keep on coding :)

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