Question

Could anybody explain why the static property is null?

class Program
{
    static void Main(string[] args)
    {
        string s = Cc.P1; // is null
    }
}

public class Cc
    : Ca
{
    static Cc()
    {
        P1 = "Test";
    }
}

public abstract class Ca
{
    public static string P1
    {
        get;
        protected set;
    }
}

Answer 1

That because when you write Cc.P1, you’re actually referring to Ca.P1 because that’s where it is declared (since P1 is static, it is not involved in polymorphism). So in spite of appearances, your code isn’t using the Cc class at all, and the Cc static constructor is not executed.