In C can a class inherit from another class and an interface

Question

I want to know if a class can inherit from a class and an interface   The example code below doesn t work but I think it conveys what I want to do  The reason that I want to do this is because at my company we make USB  serial  Ethernet  etc device  I am trying to develop a generic component interface that I can use to write programs for all our devices that will help keep the common things  like connecting  disconnecting  getting firmware  the same for all of our applications   To add to this question   If GenericDevice is in different project  can I put the IOurDevices interface in that project then then make the USBDevice class implement the interface if I add a reference to the first project  Because would like to just reference one project and then implement different interfaces depending on what the device is   class GenericDevice      private string  connectionState     public connectionState            get return  connectionState          set   connectionState   value           interface IOurDevices      void connectToDevice       void DisconnectDevice       void GetFirmwareVersion       class USBDevice   IOurDevices   GenericDevice        here I would define the methods in the interface      like this       void connectToDevice               connectionState    connected             so that in my main program I can do this     class myProgram      main              USBDevice myUSB   new USBDevice          myUSB ConnectToDevice

User · Accepted Answer

Yes  Try   class USBDevice   GenericDevice  IOurDevice   Note  The base class should come before the list of interface names   Of course  you ll still need to implement all the members that the interfaces define  However  if the base class contains a member that matches an interface member  the base class member can work as the implementation of the interface member and you are not required to manually implement it again

User · Answer

Unrelated to the question  Mehrdad s answer should get you going   and I hope this isn t taken as nitpicky  classes don t inherit interfaces  they implement them    NET does not support multiple-inheritance  so keeping the terms straight can help in communication   A class can inherit from one superclass and can implement as many interfaces as it wishes     In response to Eric s comment    I had a discussion with another developer about whether or not interfaces  inherit    implement    require   or  bring along  interfaces with a declaration like   public interface ITwo   IOne   The technical answer is that ITwo does inherit IOne for a few reasons    Interfaces never have an implementation  so arguing that ITwo implements IOne is flat wrong ITwo inherits IOne methods  if MethodOne   exists on IOne then it is also accesible from ITwo   i e    ITwo someObject  MethodOne    is valid  even though ITwo does not explicitly contain a definition for MethodOne      because the runtime says so   typeof IOne  IsAssignableFrom typeof ITwo   returns true   We finally agreed that interfaces support true full inheritance   The missing inheritance features  such as overrides  abstract virtual accessors  etc  are missing from interfaces  not from interface inheritance   It still doesn t make the concept simple or clear  but it helps understand what s really going on under the hood in Eric s world  -

User · Answer

No  not exactly  But it can inherit from a class and implement one or more interfaces   Clear terminology is important when discussing concepts like this  One of the things that you ll see mark out Jon Skeet s writing  for example  both here and in print  is that he is always precise in the way he decribes things

User · Answer

I found the answer to the second part of my questions   Yes  a class can implement an interface that is in a different class as long that the interface is declared as public

[c#] In C#, can a class inherit from another class and an interface?

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