Interfaces in C# - What they are, how to use them, and why they are so powerful.

I have watched this last year. I'm watching right now. I understood your explanation last year, and now I know way more so it's a pleasure to watch it again because I see my progress. Thanks, man.

Great job, you nailed it!

Watched multiple tutorials to try and understand what the practical point of interfaces was and none of them really explain why they're so useful. All of them explained what they are and will say they're super useful, but they never really explained why I would actually need to use them. This tutorial explained the why perfectly and now I get it, they are very useful. Thank you.

Thank you

This is the clearest explanation of interface I have seen. Thank you

You are truly a miracle for anybody learning CSharp Tim! I’ve learned so much stuff from your videos! I loved that you showed advanced technique when one interface can implement the other and then you can see methods and other stuff implemented in some concrete instance implementing one of this interfaces. Brilliant!
Thank you so much GREAT teacher! I hope that you are a very rich man because you truly deserve it!

A lot of people will jump to inheriting from a base class rather than use an interface, the more you inherit, the harder the code gets to maintain as a general rule..

Very nice explanation. Wouldn’t it be better to pass the customer inside the constructor of the IProductModel instead of through ShipItem and make ShipItem parameterless?

That way you are not forcing the CustomerModel class on everyone using IProductModels. What are you thoughts on that?

Is this Polymorphism?

Beautifully explained. Thank you !

which implementation is used more often. Implementing an interface by another interface, or having a class implement multiple interfaces?

Finally, I understand Interfaces ❤🎉🥲

I know you mentioned not using a base class and inheritance, but to me (my limited knowledge), it seems that could still work in this scenario.

Hi, I wanna point out that rather than understanding what the concept is, instead I spent more time on how your project works. Can't you create a console app and step by step add very simple implementations when you describe something.

why doesn't the private set work tho?

Thanks Sir!

Thank you very much, lots of penny's dropped :)

could you do a video that shows the full coding differences when you use interface and without interface on a same program solution?

Hello Tim,
In C#, How it comes the SqlConnection Class implements ICloneable interface, but the class does not provide a concrete implementation Or even declare the Clone() method of IColneable interface?
An explanation will be much appreciated
(Or at least provide me a link to a detailed answer, as this issue makes me frustrated about learning C#)

Code-trolls on Programming forums do exist.

Thank you Sir

I love these video's Tim! I'm an experienced programmer with various different languages, C# was never one of them, but I'm trying to pick up C# to be able to help a colleague out. Most tutorials are way too basic and beginner-oriented. Your video's exactly hit the spot for me, teaching most of the real C# "gotcha's" instead of how logic operators and if-statements work.

Thank, Tim. I was not aware that I could control the pixels level. Thank you. It's all very clear now.

Video is not viewable or clear. Too bad, good explanations and knowledge, just cannot see the video.

thanks! helped me alot

I believe there is also now a default implementation possible? Correct me of I'm wrong.

Thanks for everything

Hi Tim, thank you for your very good tutorial! Just one question: why should i prefer a public setter over a constructor variable? Thanks!

Thank you for this video. It is basic but with your explanation, It is very exciting and helpful.

I am really pleased to be doing this course as it is the best However. I find programming is really confusing tough even though I have done the microsoft book 'c sharp in 24 hours, and half of caleb curry's c sharp course. The problem is similar to accounting, where I am the only one in the world who made a basic diagram of all the accounts. And in project management where I did similar. There are no physical representations of things. I don't understand if the productmodel is 1 product, a list of products. I don't get what get and set are and why they are everywhere.

謝謝！

Thanks for this. So many videos explain what an interface is and how to use it, but not what problems it solves over basic inheritance and why you would want to use it other than because someone told you to.
This was a great practical example :)

Excellent tutorials. In depth so takes me some time reviewing, but covers the details. One thing, the issue was mentioned where an interface for example, may have only 3 properties, while the class implementing the interface may have 4 properties. And that 4th property, it cannot be access in the logic, because it's not part of the interface. It was mentioned in the tutorial there is way to access that 4th property, but then I didn't see later where that was explained. Unless ... the only way to access, is to do the "interface implementing an interface" approach? Anyway it seems like if a class has more properties than the interface it implements, the code will have problems accessing those extra class properties, without messing around with extra interfaces etc. I will have to watch the video again to see if I am understanding correctly.

Your explaning approach is truly amazing. Thanks for your effort Tim.

I finally understand this f*cking interface after tons of video, article then coming back at this with better knowledge of OOP. Basically if you want to do something with one pattern but with different values you used interface. You implement interface to modify something without destroying its initial structure. The beauty of it is you can add more methods, implementing it to a new class or to an existing class. I've watched this couple of days ago and I kinda didn't have the basic of c# and code directly so I relearn everything from classes/methods/constructors and this one. I have now fully grasp it power. This video just confirms my skeptical opinion if its true. Thank you Tim.

best video i have ever seen on interfaces ever and i've been coding for 3 years

are these videos some part of a course? because i would like to check it out.

Great video! Thanks a lot for this!!

Probably the best video on interfaces, I have seen on internet! Great job!!!

What are lists for ?

I'm sold. Subscribing now to your channel:)

OMG Somebody that explains tech as well as Scott Allen (or better ;-))! Amazing!

You save my life Tim, thank you very much. You are a true educator. I managed to understand everything and I'm not even an English speaker.

I don't know man, to me the main difference between an abstract class and interface is that abstract class can have fields and default implementations using the virtual keyword on methods, what else is different? An interface is just an complete abstract class with properties and methods with empty bodies(or a contract like you've mentioned).

In the example you've provided, why can't you use an abstract class? You said what if you have a SerivceProductModel that doesn't have a ShipItem method, you really shouldn't inherit something that's not related to the base class, sure, but all your interfaces have this ShipItem method just with different implementations, can't you achieve the same result overriding the base abstract class in a subclass? It would be clearer if you have implemented this ServiceProductModel and use that with the interface instead to show us why an abstract class wouldn't work here. Great explanation btw, but i'm still baffled on when to use an abstract class and when to use an interface.

I've seen quotes like "Interfaces do not express something like "a Doberman is a type of dog and every dog can walk" but more like "this thing can walk"", so does it mean an interface is a generic abstract class about what it can do without caring about the type?

Nice Vedio, seem all for List😀

Hey Tim, great video. FYI, the cert on the source code link expired and Chrome/Firefox are blocking access.

Thanks so much for this video Tim. It has really helped me understand interfaces.