Access rules for protected members

A friend of mine asked me a few days ago, why cannot I access the protected method of the parent class in the subclass?

The Code she saw in a book is roughly as follows:

 

Public Class

{

Public string name = "";

Protected int age = 0;

}

Public class AB:

{

Public void Init ()

{

A A = new ();

A. Name = "lifengguo ";

A. Age = 24;

}

}

 

But she is always unable to pass during compilation. She asked me why? My understanding is:

 

Protected is a protected member that can be accessed in its class and can be accessed by a derived class.

The above sentence contains three meanings:

1. The class itself can be accessed;

2. You can access the derived class;

3. the instance of the class cannot access the protected member.

 

The following code uses the protected member in the class itself.

Public Class

{

Public string name = "";

Protected int age = 0;

Public ()

{

Name = "lifengguo ";

Age = 24;

}

}

 

The following code uses the protected member in the derived class

Public class AB:

{

Public AB ()

{

Base. Name = "Li fengguo ";

Base. Age = 24;

}

}

 

The following code is a member of the Instance category class:

Public Class C

{

Public void Init ()

{

A A = new ();

AB AB = new AB ();

A. Name = "lifengguo"; // OK

AB. Name = "Li fengguo"; // OK

A. Age = 24; // Error

AB. Age = 24; // Error

}

}