Array of Objects Beginner

Question

I am developing an application in C# with winforms. I am pretty good with C++ but very new to C# so please forgive my ignorance.

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {

        public Form1()
        {
            InitializeComponent();
        }

         class obj
        {
            private int member;
            public obj(int n)
            { member = n; }

        }

        obj[] obj_arr = new obj[10];
        obj_arr[0] = new obj(4); // Problem Here
    }

}

This is a very simplified example of what I am trying to do, but as you can see I would like to declare an array of user defined objects. The problem I am having is that when I try to initialize the individual array member the compiler gives me an error. Actually it gives several errors. obj_arr[0] is highlighted with an error saying that it is a field but is being used as a type. The = is also highlighted with an error that says = is invalid token in class, struct, or interface declaration. Finally obj(4) is highlighted with an error saying method must have a return type.

I am a little stumped here, any help would be greatly appreciated.

New Code

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();

         obj_arr[0] = new obj(4); // Problem Here

    }

    class obj
    {
        private int member;
        public obj(int n)
        { member = n; }

    }

    obj[] obj_arr = new obj[10];
    obj o1 = obj_arr[0];

}

D Stanley · Accepted Answer · 2014-04-22 21:53:17Z

5

You're trying to execute code within the class definition. Only member initialization con occur outside of methods. Move that code to to another method, or the constructor:

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();

        obj_arr[0] = new obj(4); // Problem Here

        o1 = obj_arr[0];
    }

    class obj
    {
        private int member;
        public obj(int n)
        { member = n; }

    }

    obj[] obj_arr = new obj[10];

    obj o1;
}

That should make all of the compiler errors go away (one syntax error is causing another).

edited Apr 22, 2014 at 21:53

answered Apr 22, 2014 at 21:14

D Stanley

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3 Comments

mooms419 Over a year ago

Yes I agree but it was just a quick example, I would never use obj as the name of a class in real code.

mooms419 Over a year ago

Ok I think I understand whats going on a little bit better now. However I need to be able to do something like this... Edit: Wasn't able to post formatted code in this comment so I added it to the end of my original question.

D Stanley Over a year ago

That needs to be done in a method as well - I'll edit my answer.

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