Can't access members of a Template base class within a derived template class

问题

I have a template base class.Lets say.

template<class KeyF>
class Base 
{
  private:
   int member1;
   char member2;
   ....
};

I derived another class from above class.

template<class KeyF>
class Derived : public Base<KeyF>
{
  public:
  void func1() {
    <accessing member1/member2>
  }

  ....
};

Above code doesn't compile in gcc. saying that member1 is not a member of Derived. But it is already derived from a Base Class, then why can't it access its member?

回答1:

Members in Base are private. You cannot access private members of class, outside of this class (except friend). Make them protected, or make protected getters.

回答2:

Did you try protected? Been a bit since I was deep into C++...

回答3:

You need to prefix base member names with this-> or Base<KeyF>::, or add a using declaration to the class to unhide them. Their names are dependent names, and they are hidden.

来源：https://stackoverflow.com/questions/12514673/cant-access-members-of-a-template-base-class-within-a-derived-template-class