How to declare an array of an object statically

Question

I'm a long time C programmer but new to C#. I want to declare an object then creating an array of that object filling it statically (I have a very large table to enter). For example

class MyObject {
    int i1;
    string s1;
    double d1;
};

static MyObject[] myO = new MyObject {{1,"1",1.0}, {2,"2",2.0}};

This doesn't work but you get the idea. Any help appreciated.

Solution 1

Assuming you have public fields/properties on your class:

class MyObject
{
    public int i1 { get; set; }
    public string s1 { get; set; }
    public double d1 { get; set; }
}   // note: no semicolon needed here

static MyObject[] myO = { new MyObject { i1 = 1, s1 = "1", d1 = 1.0 },
                          new MyObject { i1 = 2, s1 = "2", d1 = 2.0 },
                        };

Solution 2

You need to fill the array with object instances.

Create a constructor that takes parameters, then write

new MyObject[] { new MyObject(a, b, c), new MyObject(d, e, f) }

Solution 3

You'll have to initialize the array with new object instances.

class MyObject 
{
    int i1;
    string s1;
    double d1;

    public MyObject(int i, string s, double d)
    {
        i1 = i;
        s1 = s;
        d1 = d;
    }
};

static MyObject[] myO = new MyObject[] { 
    new MyObject(1, "1", 1.0), 
    new MyObject(2, "2", 2.0)
};

Unfortunately there is no way to specify custom initializers like they are for arrays of built-in types or dictionaries. For (future) reference of what I mean:

int[] arr = { 1, 2, 3, 4 };
var list = new List<string> { "abc", "def" };
var dict = new Dictionary<string, int> { { "abc", 1 }, { "def", 2 } };

Solution 4

You'll need to instantiate the objects in the array:

static MyObject[] myO = new MyObject
{
   new MyObject { i1 = 1, s1 = "1", d1 = 1.0 },
   new MyObject { i1 = 2, s1 = "2", d1 = 2.0 },
};

Solution 5

It is exactly what you want but you can achieve your goal with following code:

class MyObject
{
    public int i1;
    public string s1;
    public double d1;
};

static MyObject[] myO = new[]  { new MyObject { i1=1, s1="1", d1=1.0 }, new MyObject { i1=2, s1="2", d1=2.0 } };

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