How can we add values to a object

The object data type (i.e. the mother of all the other types) has NOT (of course) such 'values' (i.e. data members). You have to first define your own class, for instance:

class MyObject
{
   public string number;
   public string mobile;
   public MyObject( string n, string m ){ number = n; mobile = m;}
}

and then use the way you prefer (if legal), for instance

object obj;
obj = new MyObject("666666666666", "999999999999");

You are trying to use the paradigm totally foreign to all .NET languages. Your thinking resembles JavaScript and looks totally exotic to all classical OP languages including all of the .NET, C++, Object Pascal, Python, Eiffel, whatever.

All answers on this page are correct, but your thinking is too far from the topics people are writing about. I'm not saying your thinking is wrong, it's just from a very different background, having almost nothing in common with classical OOP paradigm used by .NET. You should start with learning classical OOP paradigm from the very beginning.

Take a look: http://en.wikipedia.org/wiki/Object-oriented_programming[^].

And them, take an elementary manual on C# and .NET and try to understand the very basics. This is actually much easier to understand then the paradigm you might have come from.

—SA

And when you are a bit more experienced you can have a look at Attached Properties.
This allows you to assign foreign properties to any (Dependency)Object.

How about using a dictionary in your object , for example :

public class Person
{
  public Person()
  {

  }

  public Dictionary<string, string> Numbers = new Dictionary<string,string>();
}

And use it in this way :

Person person = new Person();
person.Numbers.Add("land tel", "+1 998 7766676");
person.Numbers.Add("mobile", "+1 878 897878");

foreach (var number in person.Numbers)
{
    Console.WriteLine("{0} = {1}", number.Key, number.Value);
}

Hope it helps.