It works, but only you the children tries to access it own variable, not variable of other instance ( even if it belongs to the same inheritance tree ). See this sample code to understand it better: //in Parent.java package parentpackage; public class Parent { protected String parentVariable = “whatever”;// define protected variable } // … Read more
Should you ever use protected member variables? Depends on how picky you are about hiding state. If you don’t want any leaking of internal state, then declaring all your member variables private is the way to go. If you don’t really care that subclasses can access internal state, then protected is good enough. If a … Read more
The webpage @MadProgrammer linked gives a decent explanation: “The protected modifier specifies that the member can only be accessed within its own package (as with package-private) and, in addition, by a subclass of its class in another package.” This means the protected member must be accessed directly through either the class it is defined in … Read more
Since B is publicly inherited from A, A’s protected member(s) become B’s protected member(s), so B can access its protected members as usual from its member function(s). That is, the objects of B can access the protected members of B from its member functions. But A’s protected members cannot be accessed outside the class, using … Read more
It’s more a stylistic thing than a direct problem. It suggests that you haven’t properly thought through what is going on with the class. Think about what static means: This variable exists at class level, it does not exist separately for each instance and it does not have an independent existence in classes which extend … Read more
Yes, it’s almost the same. The protected modifier specifies that the member can only be accessed within its own package (as with package-private) and, in addition, by a subclass of its class in another package.
When foo receives a FooBase reference, the compiler doesn’t know whether the argument is a descendant of Foo, so it has to assume it’s not. Foo has access to inherited protected members of other Foo objects, not all other sibling classes. Consider this code: class FooSibling: public FooBase { }; FooSibling sib; Foo f; f.foo(sib); … Read more
I don’t think that named parameters work in this case. So you’d have to do something like: xlwb = xlApp.Workbooks.Open(filename, False, True, None, password) See http://msdn.microsoft.com/en-us/library/office/ff194819.aspx for details on the Workbooks.Open method.
This has nothing to do with constructors specifically. This is just how protected access works. The way protected access specifier works, it allows the derived class B to access the contents of an object of base class A only when that object of class A is a subobject of class B. That means that the … Read more
The reason this doesn’t work is because C# doesn’t allow cross-hierarchy calling of protected methods. Say there was a class E that also derived from C: C / \ D E Then the reference you’re trying to call the method on could actually be an instance of type E and thus the method could resolve … Read more