Polymorphism on type of Variables in C#

Question

I have a variable in a Class with the name of Id:

public class myClass
{
    GUID Id;
}

How can I have polymorphism on the Id variable to Get either an int type or a GUID type?

I want something like this, but it only gets GUID or int:

EDIT:

public class myClass
{
    Guid || int Id;
}

I want it so that the int or Guid is defined on initialization of the class.

Answer 1

You could make the class generic:

public class MyThing<T>
  where T : struct
{
  public T MyProperty { get; set; }
}

Which then can be used the following way:

MyThing<GUID>
MyThing<int>

But to give you a valid answer, it would certainly help to know what you are trying to achieve.