Why we use interface in WCF?

Question

0.00/5 (No votes)

See more:

Hi All,

I cam up with a small doubt while working on WCF. I am looking for this answer for few days over internet but couldn't find any well-explained article on this topic.

Question 1: Why we use interface in WCF?
We could have written the operation contracts, data contracts, etc., without using interface. We could have defined a class which would simply implement the operation contracts.

Question 2: Why not Abstract class instead of interface?
We could also implement the same using an Abstract Class. I could have declared and defined the contract methods in the Abstract Class and could have simply inherit the abstract class.

Thanks:
Agnib Pyne

What I have tried:

I have searched over internet to get a perfect explanation for this doubt.

Posted 15-Oct-17 23:52pm

Member 11072126

Updated 31-Oct-20 8:27am

Add a Solution

3 solutions

Solution 3

As per my understating lets consider you have hosted one WCF service and you want to publish two method one is for your organization which will contains your companies details and other is for your client , so if you use abstract class you can either use that service for your organization or for your client.

Posted 31-Oct-20 8:28am

Member 14980454

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Kornfeld Eliyahu Peter · Accepted Answer · 2017-10-16T00:24:00

Solution 1

By definition you have not to use no interfaces and no abstract classes to use WCF...
Interfaces are considered to be the best practice because it enables a wise combination of reuses of the same contract (a class can implement multiple interfaces but can inherit only one class)...

Posted 16-Oct-17 0:24am

Kornfeld Eliyahu Peter

Comments

Member 11072126 16-Oct-17 6:38am

Thanks. I completely agree with you that I can reuse the same interface for many classes.
Now, I have one more doubt that is:
When to use Abstract Class and when to use Interface?

As far as I am concerned, Abstract Class is used for IS-A relationships and interface for HAS-A relationships. But, for HAS-A relationships also, I can use Abstract Class instead of using interface.

Secondly, if my class needs to declare variables then I can go for abstract class instead of interface. But, I can implement the same using interface as I can declare properties.

So, I cannot be able to differentiate exactly when to use abstract class and interface

Kornfeld Eliyahu Peter 16-Oct-17 6:52am

Google for 'C# Abstract Class vs Interface' and start reading...

Member 11072126 16-Oct-17 7:06am

Yes, I have read various articles. But, the only valid point am getting is that I for interfaces, I can be implement multiple interfaces but not possible with abstract class. The other points, when analyzed, can be seen that the same thing is possible for both abstract class and interface.

OriginalGriff · Accepted Answer · 2017-10-16T00:32:00

Turn the question round: what happens if you don't use an Interface?

Well, there are then two ways to do it:
1) Define an abstract class.
2) Define a concrete class.

What is the "advantage" of an abstract class over an interface here? Well, you can add predefined behaviour to the class to add default processing - but WCF isn't about processing, it's about data transfer: all the processing that can be defaulted has been done at the remote end already. So what exactly can you add to the abstract class that is of any use to all users of the data? In practice, nothing - because you have no idea what the data will be used for.

What about a concrete class? Same problems as the abstract class, with no really benefits.

And both of them cause a major problem, because C# does not support multiple inheritance. So if you use an abstract or concrete class you cannot derive from any other class. Which means you can't create a TextBox that "knows" about your WCF source because you can't derive from Control, TextBox, or any other UI component and from the WCF class at the same time.

Interfaces have none of those restrictions, so it's a much, much better choice. It forces you to implement the data transfer contract requirements, without restricting what you can subsequently do with the data in your implementation.