.NET Tips and Tricks

Blog archive

Inheriting Interfaces

It's no secret that I love interfaces (I did a whole column about them once). As you add more interfaces to your application you may find that you have several interfaces that look very much alike. These two, for example:

Public Interface ICustomer
    Property Id As Integer
    Property Name As String
    Sub Buy()
End Interface

Public Interface IVendor
    Property Id As Integer
    Property Name As String
    Sub Sell()
End Interface

But, looking at those interfaces, there's obviously the idea of a "business partner" buried in this interface design in the shared Id and Name property. It wouldn't be surprising to find that there are other interfaces in this application that share those Id and Name properties.

You can implement that "business partner" (and simplify maintenance of your application) by defining the business partner interface and then having the ICustomer and IVendor interfaces inherit from it. The result would look like this:

Public Interface IBusinessPartner
    Property Id As Integer
    Property Name As String
End Interface

Public Interface ICustomer
    Inherits IBusinessPartner
    Sub Buy()
End Interface

Public Interface IVendor
    Inherits IBusinessPartner
    Sub Sell()
End Interface

There are lots of benefits to building this inheritance structure: You can now extend both the IVendor and ICustomer interfaces with shared members by adding them to IBusinessPartner. If you ever need to add another "business partner" interface, all the common work is done for you: Your new interface just needs to inherit from IBusinessPartner.

Finally, a variable declared as IBusinessPartner will work with any class that implements ICustomer or IVendor, giving your application more flexibility.

Posted by Peter Vogel on 01/22/2015 at 2:20 PM


comments powered by Disqus

Featured

  • How to Do Naive Bayes with Numeric Data Using C#

    Dr. James McCaffrey of Microsoft Research uses a full code sample and screenshots to demonstrate how to create a naive Bayes classification system when the predictor values are numeric, using the C# language without any special code libraries.

  • Vortex

    Open Source 'Infrastructure-as-Code' SDK Adds .NET Core Support for Working with Azure

    Pulumi, known for its "Infrastructure-as-Code" cloud development tooling, has added support for .NET Core, letting .NET-centric developers use C#, F# and VB.NET to create, deploy, and manage Azure infrastructure.

  • .NET Framework Not Forgotten: Repair Tool Updated

    Even though Microsoft's development focus has shifted to the open-source, cross-platform .NET Core initiative -- with the aging, traditional, Windows-only .NET Framework relegated primarily to fixes and maintenance such as quality and reliability improvements -- the latter is still getting some other attention, as exemplified in a repair tool update.

  • How to Work with C# Vectors and Matrices for Machine Learning

    Here's a hands-on tutorial from bona-fide data scientist Dr. James McCaffrey of Microsoft Research to get you up to speed with machine learning development using C#, complete with code listings and graphics.

  • Sign

    Working with Claims to Authorize Users in ASP.NET Core and Blazor

    When you need to integrate authorizing the user to perform some activity (or just want to retrieve information about the current user), you need to work with the ClaimsPrincipal’s Claims objects. Here’s everything you might want to do.

.NET Insight

Sign up for our newsletter.

Terms and Privacy Policy consent

I agree to this site's Privacy Policy.

Upcoming Events