“Surely so long as you allocate memory on the heap” – where the memory is allocated has nothing to do with it. It’s all about the semantics. Take, for instance: Derived d; Base* b = &d; d is on the stack (automatic memory), but polymorphism will still work on b. If you don’t have a … Read more
The virtual keyword is used to modify a method, property, indexer or event declaration, and allow it to be overridden in a derived class. For example, this method can be overridden by any class that inherits it: Use the new modifier to explicitly hide a member inherited from a base class. To hide an inherited … Read more
This warning is there to prevent accidental hiding of overloads when overriding is intended. Consider a slightly different example: struct chart; // let’s pretend this exists struct Base { virtual void* get(char* e); }; struct Derived: public Base { virtual void* get(chart* e); // typo, we wanted to override the same function }; As it … Read more
The Virtual Modifier is used to mark that a method\property(ect) can be modified in a derived class by using the override modifier. Example: class A { public virtual void Foo() //DoStuff For A } class B : A { public override void Foo() //DoStuff For B //now call the base to do the stuff for … Read more
There are two ways. The first one is by specifying the interface statically for the structure of types: template <class Derived> struct base { void foo() { static_cast<Derived *>(this)->foo(); }; }; struct my_type : base<my_type> { void foo(); // required to compile. }; struct your_type : base<your_type> { void foo(); // required to compile. }; … Read more
virtual was never required in EF. It was needed only if you want lazy loading support. Since Lazy loading is not yet supported by EF Core, currently virtual have no special meaning. It would when (and if) they add lazy loading support (there is a plan for doing so). Update: Starting with EF Core 2.1, … Read more
No, there’s no way to do it, since what would happen when you called Object::GetTypeInformation()? It can’t know which derived class version to call since there’s no object associated with it. You’ll have to make it a non-static virtual function to work properly; if you also want to be able to call a specific derived … Read more
From wikipedia In Java, all non-static methods are by default “virtual functions.” Only methods marked with the keyword final, which cannot be overridden, along with private methods, which are not inherited, are non-virtual.
It allows the Entity Framework to create a proxy around the virtual property so that the property can support lazy loading and more efficient change tracking. See What effect(s) can the virtual keyword have in Entity Framework 4.1 POCO Code First? for a more thorough discussion. Edit to clarify “create a proxy around”: By “create … Read more
From Wikipedia’s Virtual function … In object-oriented programming, in languages such as C++, and Object Pascal, a virtual function or virtual method is an inheritable and overridable function or method for which dynamic dispatch is facilitated. This concept is an important part of the (runtime) polymorphism portion of object-oriented programming (OOP). In short, a virtual … Read more