在没有基本关键字的情况下访问由静态变量隐藏的实例变量

Question

How come I can't access the hidden instance variable a in the line (int gimmeValue = shinyNewBObject.a;) ? I understand that I can use the base keyword to access the instance a. However, I thought that the compiler would use the object reference in shinyNewBObject to rule out static variables. If the static version of a is ruled out, the instance version of a would become unhidden and therefore accessible.

What's going on here? Did the compiler create a list of all a identities in the assembly and ruled out the instance variable because it's hidden before it ruled out the other a because it's static?

class A
{
    public int a;
}

class B : A
{
    new public static int a;

    public void m()
    {
        B shinyNewBObject = new B();
        int gimmeValue = shinyNewBObject.a; //Error
        gimmeValue = base.a;
    }
}

Answer 1

我不能完全确定C＃规范的哪一部分规定了为什么子类中的静态字段遮盖了基类型变量时为什么不让您访问基类型变量，但是要解决此问题，您可以将其强制转换为A ：

int gimmeValue = ((A)shinyNewBObject).a; 

Answer 2

I think I found the answer:

I needed to look at the member look-up section of the specification (7.4).

"the effect of the look-up rules is simply that derived members hide base members with the same name or signature. Such single-inheritance look-ups are never ambiguous."

I think what happens when aobj.a is considered by the compiler is aobj is ignored for the time being and just a is considered.

The compiler goes to the A class definition which has all of the static and instance members implicitly or explicitly and sees the two a members. Both are accessible based on (3.5) so they go in the set of possibilities. Then the hidden variable is removed leaving the static one.

Finally 'aobj' is considered and an error occurs because an instance reference can't access the static variable.

There might be some problems with my story. If so, please correct me because I made some guesses.