Visual Basic 2015 Unleashed

Defining Interfaces

An interface is a reference type defined within an Interface..End Interface block. Interfaces define only signatures for members that classes will then expose and are a set of the members’ definitions. Imagine you want to create an interface that defines members for working with documents. This is accomplished with the following code:

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Public Interface IDocument    Property Content As String    Sub Load(ByVal fileName As String)    Sub Save(ByVal fileName As String)End Interface

The interface is marked as Public because the default scope for interfaces is Friend. Assigning public visibility ensures that external assemblies use the interface (which is a common scenario).

Interfaces Scope

Interfaces ...