Learning C#

Explicit Interface Implementation

In the implementation shown so far, the implementing class (Document) creates a member method with the same signature and return type as the method detailed in the interface. It is not necessary to explicitly state that this is an implementation of an interface; this is understood by the compiler implicitly.

What happens, however, if the class implements two interfaces, each of which has a method with the same signature? This might happen if the class implements interfaces defined by two different organizations or even two different programmers. The next example creates two interfaces: IStorable and ITalk. The latter implements a Read() method that reads a book aloud. Unfortunately, this conflicts with the Read() method in IStorable.

Because both IStorable and ITalk have a Read() method, the implementing Document class must use explicit implementation for at least one of the methods. With explicit implementation, the implementing class (Document) explicitly identifies the interface for the method:

void ITalk.Read()

Marking the Read() method as a member of the ITalk interface resolves the conflict between the identical Read() methods. There are some additional aspects you should keep in mind.

First, the explicit implementation method cannot have an access modifier:

void ITalk.Read()

This method is implicitly public. In fact, a method declared through explicit implementation cannot be declared with the abstract, virtual, override, or new keywords. ...