static-members

问题 I'm using log4net, and we have a lot of this in our code: public class Foo { private static readonly ILog log = LogManager.GetLogger(typeof(Foo)); .... } One downside is that it means we're pasting this 10-word section all over, and every now and then somebody forgets to change the class name. The log4net FAQ also mentions this alternative possibility, which is even more verbose: public class Foo { private static readonly ILog log = LogManager.GetLogger(System.Reflection.MethodBase

问题 I'm using log4net, and we have a lot of this in our code: public class Foo { private static readonly ILog log = LogManager.GetLogger(typeof(Foo)); .... } One downside is that it means we're pasting this 10-word section all over, and every now and then somebody forgets to change the class name. The log4net FAQ also mentions this alternative possibility, which is even more verbose: public class Foo { private static readonly ILog log = LogManager.GetLogger(System.Reflection.MethodBase

问题 I have a generic class: public class Foo<T> where T: Interface { } the interface that T is being forced to implement has 2 static methods defined inside of it. in the constructor I want to be able to basically do the following: public Foo() { value1 = T.staticmethod1(); value2 = T.staticmethod2(); } This cannot be accomplished with the psuedocode I have posted above. Is it not possible to call these static methods in this way? 回答1: You may be able to use extension methods. This technique has

问题 Just like the way we save the instance variables using serialization, is there any way by which I can save the state of static members? If there is a situation, where getting back the state of static members is necessary to restore something, how would one do that? 回答1: The easiest option that comes to my mind is to use a singleton rather than static fields. The singleton object can be serialized and deserialized, and you can manage its lifetime, while you preserve the 'global state' that

问题 I have a simple question here. If I declare a variable inside an object which was made [declared] in the main class, like this: public static int number; ( usually I declare it like this : private int number; ) can it be used in a different object which was also made [declared] in the main class? btw I do not care about security atm, I just want to make something work, don't care about protection) 回答1: Here's a telling quote from Java Language Specification: JLS 8.3.1.1 static Fields If a

问题 I'm trying to figure out why this example doesn't compile. My understanding is that if a static variable is not explicitly set then it defaults to 0. In the five examples below four of them behave as I would expect, but the one that's commented out won't compile. #include <iostream> class Foo { public: static int i; static int j; }; template <int n> class Bar { public: Bar(int) { } static int i; }; static int i; int Foo::i; int Foo::j = 1; template <> int Bar<2>::i; template <> int Bar<3>::i

问题 I was inspired by the comments under this question. I didn't see any reason why a class with only static functions would be a better design than a namespace (with just functions). Any list of pros and cons of these two approaches are welcomed. It would be great with some practical examples! 回答1: One non-stylistic difference is that you can use a class as a template parameter, but you cannot use a namespace. This is sometimes used for policy classes, like std::char_traits. Outside of that use

问题 Let we have two members equal by signature, but one is static and another - is not: class Foo { public void Test() { Console.WriteLine("instance"); } public static void Test() { Console.WriteLine("static"); } } but such code generate brings a compiler error: Type 'Foo' already defines a member called 'Test' with the same parameter types But why? Let we compiled that successfully, then: Foo.Test() should output "static" new Foo().Test(); should output "instance" Can't call the static member

问题 This code is giving me incomplete type error. What is the problem? Isn't allowed for a class to have static member instances of itself? Is there a way to achieve the same result? struct Size { const unsigned int width; const unsigned int height; static constexpr Size big = { 480, 240 }; static constexpr Size small = { 210, 170 }; private: Size( ) = default; }; 回答1: Is there a way to achieve the same result? By "the same result", do you specifically intend the constexpr -ness of Size::big and

问题 Every time I come across an implementation of the singleton pattern or any static classes (i.e. classes with (almost) only static members) I wonder whether this isn't actually a hack and therefore heavy abuse of the principle of classes and instances just to design single objects instead of designing classes and creating a single instance. To me, it looks like static members of classes in general try to add some sort of characteristics to classes which they actually aren't supposed to have