static-classes | 易学教程

Error: Extension methods must be defined in a top level static class (CS1109)

阅读更多关于 Error: Extension methods must be defined in a top level static class (CS1109)

I'm trying to make a countdown program, which I can start and stop and set the value of the countdown to 10 minutes if needed. But I'm getting an error I don't quite understand. I'm not that into C#, so here's the code: Can some one help me a bit here ? Think I run on framework 3.0 or something ? using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Timers; namespace PauseMaster { public partial class MainForm : Form { public MainForm() {

Why does Android prefer static classes

阅读更多关于 Why does Android prefer static classes

I see a lot of java code where android prefers to have developers use static inner classes. Particularly for patterns like the ViewHolder Pattern in custom ListAdapters. I'm not sure what the differences are between static and non-static classes. I've read about it but it doesn't seem to make sense when concerned with performance or memory-footprint. It's not just Android developers... A non-static inner class always keeps an implicit reference to the enclosing object. If you don't need that reference, all it does is cost memory. Consider this: class Outer { class NonStaticInner {} static

What is a “static” class?

阅读更多关于 What is a “static” class?

问题 In C# what is the difference between: public static class ClassName {} And: public class ClassName {} 回答1: A static class cannot be instantiated, and can contain only static members. Hence, the calls for a static class are as: MyStaticClass.MyMethod(...) or MyStaticClass.MyConstant . A non static class can be instantiated and may contain non-static members (instance constructors, destructor, indexers). A non-static member of a non-static class is callable only through an object:

Why do members of a static class need to be declared as static? Why isn't it just implicit?

阅读更多关于 Why do members of a static class need to be declared as static? Why isn't it just implicit?

Obviously there can't be an instance member on a static class, since that class could never be instantiated. Why do we need to declare members as static? I get asked questions like this all the time. Basically the question boils down to "when a fact about a declared member can be deduced by the compiler should the explicit declaration of that fact be (1) required, (2) optional, or (3) forbidden?" There's no one easy answer. Each one has to be taken on a case-by-case basis. Putting "static" on a member of a static class is required. Putting "new" on a hiding, non-overriding method of a derived

Why do members of a static class need to be declared as static? Why isn't it just implicit?

阅读更多关于 Why do members of a static class need to be declared as static? Why isn't it just implicit?

问题 Obviously there can\'t be an instance member on a static class, since that class could never be instantiated. Why do we need to declare members as static? 回答1: I get asked questions like this all the time. Basically the question boils down to "when a fact about a declared member can be deduced by the compiler should the explicit declaration of that fact be (1) required, (2) optional, or (3) forbidden?" There's no one easy answer. Each one has to be taken on a case-by-case basis. Putting

Static Classes In Java

阅读更多关于 Static Classes In Java

问题 Is there anything like static class in java? What is the meaning of such a class. Do all the methods of the static class need to be static too? Is it required the other way round, that if a class contains all the static methods, shall the class be static too? What are static classes good for? 回答1: Java has static nested classes but it sounds like you're looking for a top-level static class. Java has no way of making a top-level class static but you can simulate a static class like this:

This Handler class should be static or leaks might occur: IncomingHandler

阅读更多关于 This Handler class should be static or leaks might occur: IncomingHandler

问题 I\'m developing an Android 2.3.3 application with a service. I have this inside that service to communicate with Main activity: public class UDPListenerService extends Service { private static final String TAG = \"UDPListenerService\"; //private ThreadGroup myThreads = new ThreadGroup(\"UDPListenerServiceWorker\"); private UDPListenerThread myThread; /** * Handler to communicate from WorkerThread to service. */ private Handler mServiceHandler; // Used to receive messages from the Activity

Java inner class and static nested class

阅读更多关于 Java inner class and static nested class

问题 What is the main difference between an inner class and a static nested class in Java? Does design / implementation play a role in choosing one of these? 回答1: From the Java Tutorial: Nested classes are divided into two categories: static and non-static. Nested classes that are declared static are simply called static nested classes. Non-static nested classes are called inner classes. Static nested classes are accessed using the enclosing class name: OuterClass.StaticNestedClass For example, to