Question

Array of Pairs <string, unsigned long>

• Array has constant number of elements(8).

• Fields string filled (not null, PRIMARY KEY), and never change its values.

• Fields unsigned long filled with null by default, then change its values in runtime.

• There will be a lot of such objects.

Answer 1

Wild guess…

public class MyData
{
    private Dictionary<string, ulong> _prop1=new Dictionary<string, ulong>(8);

    public Dictionary<string, ulong> Prop1
    {
        get { return _prop1; }
        set { _prop1 = value; }
    }

    public string CityName { get; set; }

    public ulong? Population { get; set; }
}

And for the a lot of this:

var alotofobject s= new List<MyData>();

Edit:

Allright, now I see what you need:

var cities=new Dictionary<string,ulong>(8);
cities.Add("City1",0);
cities.Add("City2",0);
cities.Add("City3",0);
cities.Add("City4",0);
cities.Add("City5",0);
cities.Add("City6",0);
cities.Add("City7",0);
cities.Add("City8",0);

If you want to set or get the population of a city, just use:

cities["City1"]=293238;

var populationOfCity1=cities["City1"];

And as a suggestion, please get a beginner book for C#.