 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
.NET Forum / Languages / C# / January 2008Multiple Interface implementation with same methods
Hi, Consider a situation where a class (Say C1) is implementing two interfaces (I1, I2). Both the interface contains a method (M1) with the same signature. class C1:I1, I2 { //implementation of M1 only once } I wanna understand why we need only one implementation of M1. It voilates the principle which says we must provide implementation of every method for all the interfaces. In any case which interface's M1 is being implemented here i mean I1 or I2? Thanks Mukesh > It voilates the principle which says we must provide implementation > of > every method for all the interfaces. No it doesn't... we *have* provided an implementation for each... they just aren't *different* implementations. Both I1 and I2 will pick up the implicit interface implementation from M1 via the public M1 method, as per the language spec. You can, however, opt to make either (or both) implementations explicit: class C1 : I1, I2 { public void M1() {...} void I2.M1() {...} } Here there is an explicit imlementation for I2.M1(); however, when checking I1, there is no explicit implementation, so it checks for matching public methods - which it finds (an implicit implementation). Marc > > It voilates the principle which says we must provide implementation > > of [quoted text clipped - 18 lines] > > Marc Hi, Marc That's fine. Now if two interfaces accidentally have a method with same signature but we want different functional implementaion of both the methods. Can we use some different names (say M2 and M3) while implementing I1.M1() and I2.M1() so that its more logical for the users of class C1. Thanks Mukesh <snip> > That's fine. Now if two interfaces accidentally have a method with > same signature but we want different functional implementaion of both > the methods. Can we use some different names (say M2 and M3) while > implementing I1.M1() and I2.M1() so that its more logical for the > users of class C1. No. Users of the class who want to use it "as" a particular interface need to cast to that interface. Jon > <snip> > [quoted text clipped - 6 lines] > No. Users of the class who want to use it "as" a particular interface > need to cast to that interface. Maybe I didn't understand the question correctly, but I think he's asking whether two public methods M2 and M3 that would be used outside the context of the interface can be used as the implementation for each of the interface methods as well. If so, then the answer is basically yes. I mean, you can't alias the method names or anything like that, but you can just have the interface methods call some other method directly. So I1.M1() could call M2 and I2.M1() could call M3. You're right that when the interface methods are declared explicitly, a cast is needed to get at them. But I didn't think that's what Mukesh was asking. Pete On Jan 10, 8:20 am, "Peter Duniho" <NpOeStPe...@nnowslpianmk.com> wrote: > > No. Users of the class who want to use it "as" a particular interface > > need to cast to that interface. [quoted text clipped - 12 lines] > cast is needed to get at them. But I didn't think that's what Mukesh was > asking. I think he was asking about the aliasing side. I *believe* that VB.NET actually lets you do that. But yes, explicit interface implementation which calls a public/internal method with a more descriptive name is an easy way of getting round the limitation. Jon > On Jan 10, 8:20 am, "Peter Duniho" <NpOeStPe...@nnowslpianmk.com> > wrote: [quoted text clipped - 24 lines] > > - Show quoted text - Hi Jon, You are right. Actually method names for a class should signify the functionality it provides. Since the method name for the two methods is same that may be a bit ambiguous for the user using that class. So I wanted to refine the names in the context of that class to reflect the implementation functionality. Thanks for the solution. Mukesh Aside (for the OP's benefit): what you describe is supported at the IL level (and VB allows this usage natively), but it isn't possible via C#. But as Peter observes, it is trivial to just forward the methods from the explicit implementations. Marc Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
|
Reply to this Message
|
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.