interface

问题 I'm facing a problem regarding multiple inheritance in VB.net: As far as I know VB.net does not support multiple inheritance in general but you can reach a kind of multiple inheritance by working with interfaces (using “Implements” instead of “Inherits”): Public Class ClassName Implements BaseInterface1, BaseInterface2 End Class That works fine for classes but I’d like to have an interface inheriting some base interfaces. Something like that: Public Interface InterfaceName Implements

问题 Consider a class which implements a lot of interfaces, would it make sense to implement each interface in a separate file using partial class definitions? Would this be an abuse of the language feature or is it an idiom I'm unaware of? 回答1: If your class has to implement many interfaces, that's a reasonable way of managing the source, yes. You can edit the project file to make several of them depend on one "main" class file, which makes the Solution Explorer easier to work with. You should

问题 Consider this code: @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface Bar { Foo foo() default FooImpl.FooConstant; } Compiler error: annotation value not of an allowable type If I replace Foo with FooImpl the code is accepted. What's the reason for this behavior? 回答1: If I replace Foo with FooImpl the code is accepted. I would be very surprised if this compiled, unless FooImpl is an enum. Annotation members may only contain the following: primitive type String

问题 In Java 8, is it better for interface or abstract class to define APIs returning CompletableFuture instead of returning Future ? Considering it is ugly converting Future to CompletableFuture and the fact that CompletableFuture will give the caller more flexibility of using functional style directly, what could be a good reason for an API to just return Future ? 回答1: My 2 cts: by returning a Future, you keep your options open and can return a Future, or a CompletableFuture - it makes no

问题 If I have the following interfaces and a class that implements them - IBase = Interface ['{82F1F81A-A408-448B-A194-DCED9A7E4FF7}'] End; IDerived = Interface(IBase) ['{A0313EBE-C50D-4857-B324-8C0670C8252A}'] End; TImplementation = Class(TInterfacedObject, IDerived) End; The following code prints 'Bad!' - Procedure Test; Var A : IDerived; Begin A := TImplementation.Create As IDerived; If Supports (A, IBase) Then WriteLn ('Good!') Else WriteLn ('Bad!'); End; This is a little annoying but

问题 I write below in a single php file. <?php interface people { public function take($s); } class engineer extends people { public function take($s){ echo $s; } } ?> The people is an interface, the engineer extends people. But when I run this code, the error: Fatal error: Class engineer cannot extend from interface people in E:\php5\Mywwwroot\b.php on line 12 What's happened? My PHP version is 5.4. 回答1: You implement interfaces and extend classes: <?php interface people { public function take($s

问题 I have two interfaces; interface ISuccessResponse { Success: boolean; Message: string; } and interface IAppVersion extends ISuccessResponse { OSVersionStatus: number; LatestVersion: string; } I would like to extend ISuccessResponse interface as Not Required; I can do it as overwrite it but is there an other option? interface IAppVersion { OSVersionStatus: number; LatestVersion: string; Success?: boolean; Message?: string; } I don't want to do this. 回答1: A bit late, but Typescript 2.1

问题 I'm building an Angular 4 project in Typescript 2.3.4 . I can't figure out what's wrong with the code below. IDialog interface export interface IDialog{ cancellable?: boolean, inputs?: Array<{label: string, value?: any, description?: string}|string> message: string title?: string, type?: DialogInputTypes // <- an Enum } SampleComponent.ts public dialog:IDialog = { cancellable:false, title:'Dialog Title', message:'This is a modal dialog', type:DialogInputTypes.button, inputs:[ {label:'OK',

问题 I have the following base interface public interface IHandler{ void Handle(IMessage message); } and an generic interface inheriting the base interface public interface IHandler<TMessage> : IHandler where TMessage : IMessage{ void Handle(TMessage message); } My classes can implement the interface IHandler<TMessage> mutiple times. IMessage is an base interface for messages and isn´t relevant here. Currently i´m implementing the interfaces as follows. public class ExampleHandler : IHandler

问题 I have had trouble finding help in the matlab documentation and previous questions about using matlab inheritance and class constructors to make an interface. To make it tidy, within a package. Instead of dragging through my code I can condense it as follows: A package +MyPkg has a superclass Super and a few subclasses Sub1 Sub2 ... Most of my properties and methods are defined in Super such that Sub1 and Sub2 really only exist to use their constructors for simple routines or perhaps a few