In this example, the interface contains the property declaration and the class contains the implementation. The following example demonstrates interface implementation. In addition, default interface members can only be accessed through an instance of the interface.įor more information about explicit interface implementation, see Explicit Interface Implementation. An explicitly implemented member can't be accessed through a class instance, but only through an instance of the interface. When a base type list contains a base class and interfaces, the base class must come first in the list.Ī class that implements an interface can explicitly implement members of that interface. When an interface overrides a method implemented in a base interface, it must use the explicit interface implementation syntax. Instead, it declares a property that doesn't have a default implementation but must be implemented in any type that implements the interface: public interface INamedĪn interface can inherit from one or more base interfaces. In an interface declaration, the following code doesn't declare an auto-implemented property as it does in a class or struct. This rule has a subtle effect on property declarations. Instance auto-properties aren't supported in interfaces, as they would implicitly declare a hidden field. While static fields are now permitted, instance fields aren't permitted in interfaces. Interfaces may not contain instance state. You can try this feature by working with the tutorial on static abstract members in interfaces. If the runtime type of an expression is derived from a different compile time type, the static methods on the base (compile time) type will be called. Method dispatch for static abstract and static virtual methods declared in interfaces is resolved using the compile time type of an expression. Alternatively, when double is the type argument, the static members declared on the double type are invoked. When the type parameter T denotes the type argument int, the static members declared on int are invoked. For example, the int type implements INumber. The compiler uses the type argument to resolve calls to the methods and operators declared in the interface declaration. For example, the INumber interface declares that T must implement INumber. Furthermore, most interfaces that declare static virtual or static abstract methods declare that one of the type parameters must implement the declared interface. Therefore, static virtual methods are almost exclusively declared in generic interfaces. Instead, the compiler uses type information available at compile time. The static virtual and static abstract methods declared in interfaces don't have a runtime dispatch mechanism analogous to virtual or abstract methods declared in classes. The compiler must resolve calls to static virtual and static abstract methods at compile time. These interfaces define common mathematical operators that are implemented by many numeric types. You can see examples in the numeric types in the. This feature enables generic algorithms to specify number-like behavior. Interfaces can declare that implementing types must define operators or other static members. Explicit access modifiers (the default access is public).īeginning with C# 11, an interface may declare static abstract and static virtual members for all member types except fields.Member declarations using the explicit interface implementation syntax.Static fields, methods, properties, indexers, and events.Members with bodies permit the interface to provide a "default" implementation for classes and structs that don't provide an overriding implementation. Member bodies in an interface are the default implementation. These preceding member declarations typically don't contain a body. An interface declaration can contain declarations (signatures without any implementation) of the following members: ISampleInterface obj = new ImplementationClass() Īn interface can be a member of a namespace or a class. Explicit interface member implementation: Example interface interface ISampleInterfaceĬlass ImplementationClass : ISampleInterface In the following example, class ImplementationClass must implement a method named SampleMethod that has no parameters and returns void.įor more information and examples, see Interfaces. Typically, static virtual methods declare that an implementation must define a set of overloaded operators. Beginning with C# 11, an interface may define static abstract or static virtual members to declare that an implementing type must provide the declared members. It may also define static members in order to provide a single implementation for common functionality. An interface may define a default implementation for members. Any class or struct that implements that contract must provide an implementation of the members defined in the interface.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |