why our C++ class is forced abstract?

Why when we inherit an abstract C# class defined in a .dll, our C++-CLI class is forced abstract?

is there any 开发者_运维问答way to make it not abstract our c++-CLI class?

---

I'm not sure I understood your question correctly, but you have to implement all the methods declared but not implemented in the abstract base class, otherwise naturally your class is considered abstract as well.

---

If your class declares any methods that are "pure virtual" (i.e., with "= 0"), or inherits any pure virtual methods without overriding them, your class will be abstract.

---

class A
{
public:
    virtual void fun() = 0; //"pure" virtual function
    virtual void gun() = 0; //"pure" virtual function

    virtual void sun() //virtual function - "not pure"
    {
      /***** implementation code *****/
    }
};

Here A is an abstract class, since it has two pure virtual functions.

class B : public A
{
public:
    virtual void fun() 
    {
       /******* implementation code ********/
    }
};

Question: What is B? Is it non-abstract? After all, it has defined/implemented one pure virtual function called fun()?

Answer : No. B too is an abstract class, because it didn't define/implement gun() which too is pure virtual function in the base class A. Defining just one pure virtual function called fun() doesn't make it non-abstract. It has to define ALL pure virtual functions. ALL means ALL, as many as there are pure virtual functions.

So two important notes here : 1) pure virtual functions, 2) define all of them. Only then a class can become concrete/non-abstract!