Reference variable from a different method, class, file

Question

I need to reference the value of a variable in a different method, class, and file than the one I am currently in. I am brand new to C# and still trying to get these concepts.

Answer 1

Can this not be done with a public property?

public class Service
{
    public bool MyVariable { get; set; }
    public bool AddRoute(l, m, n)
    {
        MyVariable = xyz;
    }
}