How to: Create and Implement Interfaces
As explained in Interfaces Overview, interfaces describe the properties, methods, and events of a class without providing any implementation.
To create an interface
Define your interface by adding code to it that begins with the Interface keyword and the name of the interface, and ends with the End Interface statement. For example, the following code defines an interface named IAsset.
Interface IAsset End Interface
Add statements that define the properties, methods, and events your interface supports. For example, the following code defines one function, one property, and one event.
Interface IAsset Event ComittedChange(ByVal Success As Boolean) Property Division() As String Function GetID() As Integer End Interface
To implement an interface
If the interface that you are implementing is not part of your project, add a reference to the assembly containing the interface.
Create a new class that implements your interface, and include the Implements keyword in the line following the class name. For example, to implement the IAsset interface, you could name the implementation class Computer, as in the following code.
Class Computer Implements IAsset End Class
Add procedures to implement the properties, methods, and events of the class as in the following code, which builds on the example in the previous step:
Class Computer Implements IAsset Public Event ComittedChange(ByVal Success As Boolean) _ Implements IAsset.ComittedChange Private divisionValue As String Public Property Division() As String _ Implements IAsset.Division Get Return divisionValue End Get Set(ByVal value As String) divisionValue = value RaiseEvent ComittedChange(True) End Set End Property Private IDValue As Integer Public Function GetID() As Integer _ Implements IAsset.GetID Return IDValue End Function Public Sub New(ByVal Division As String, ByVal ID As Integer) Me.divisionValue = Division Me.IDValue = ID End Sub End Class