So many tutorials on the web, but I get the feeling your are the dean of developers.

It is good video. you explain the start up writing on extension methods in seperate class and meaning the this key word more super. i confused in this understanding but now i am so clear. Thank you tim corey

Gotta say it physically hurt when you put your extension class in the System namespace, good thing you mentioned that it should NOT be used like that.

I'm still a student, and I promise you, you will receive a portion of my first salary. Thank you so much for these valuable resources. You couldn't imagine the feeling of joy when I search for a topic and find one of your videos among the results.

Thanks for this Tim. One interface I frequently extend in most libraries I write is the IServiceCollection so that setting up dependency injection for the library is easier to consume. I appreciate your expertise on these topics.

Thank you! I followed the tutorial and then created the .sln/.csproj on my own. Very nice intro to extension methods. Now, with great power comes great responsibility!

Thanks Tim. The way you make me understand is awesome.

That was amazing. Learning things so quickly with these tutorials. Thanks Tim.

I've used extension methods, but only ones I found. I had a bunch saved/bookmarked. I honestly thought it had to do something with how you named things or something in the standard libraries I just wasn't aware of... it was just "this class". It makes so much sense now!

Perfect timing and found your tournament course also using this technique for the textConnector

I'm very happy because this is the first time I did know how to do all the things that this video has demonstrated. Yeiii!! Thank you Tim, you're the best!!!

Great video. Tim, thank you for such a detail, organized, and straightforward demonstration of method extension. You really are making C# easy.

Excellent lesson as usual! I am using my extension methods for manual mappings when I need to convert Model to DTO and vice versa. It works like charm.

Hi, Tim! You're a great teacher!

Thank you, I had seen these syntaxes before but I never knew what it did.

Perfect timing! Just when I thought where to implement extension methods in my pet project for portfolio.

Looking forward to seeing some videos about DDD, Microservices, and ElasticSearch.

Wonderful, very helpful lecture this is! Thanks, Tim. After seeing this class, I am eager to know the counterparts on properties or fields.

Thank you, I have been looking for a good tutorial on extention methods, popped up at a great time.

Holy shit why had no one taught me this sooner! Awesome

Needed this last week! Thanks though

Love these things. Been using them for awhile, they write and read much easier. I like to wrap existing string functionality so I can do: string myString = ""; if (myString.IsNullOrEmpty()) ... and then just have the extension method like so. public static bool IsNullOrEmpty(this string str) { return string.IsNullOrEmpty(str); } Or better yet, when writing logic to append a middle name... public static string AppendIfNotNull(this string str, string textToAppend, string separator = ", ") { if (textToAppend.IsNullOrEmpty()) { return str; } return $"{str}{separator}{textToAppend}"; }

I knew the first part, but that string at 7.30 just blew my mind.

I am new to C# and I really like your way of teaching.I have request could a make a video on various commands in C#

Thank you for this informative video, I am learning .NET concepts wise and this really helped clarify the purpose of extension methods!

Thank you, Tim! It's a great course!

I actually found lots of good use for extending even the string type. For example, I have an extension where a person has a month spelled out and it returns the number from 1 to 12. Another one I have for strings is if a person has a sentence and need to know the month integer found in the string, then I have it as well. Even being able to easily generate a comma delimited list. The truth is even for the simple types like string ,integers, there are many useful extensions that can be created. One good one for int is being able to convert to any enum as long as the number sent matches the number it corresponds to in the enum. There are many other examples of good extensions for all simple types.

Another great one Tim!

awesome tutorial! Thanks

Great video and great topic....too many people out there don't use that feature

That's exactly what they are demanding me to know. Thanks for awesome content

thank you Tim , can you please how we can Mock Testing our Extention Methods as they are static

Hey Tim, thanks for a great video and channel. Was just also watching your async video. Do u have any plans on making a Thread video as well?

very well as always. Thanks

Excellent tutorial! Thank you very much.

Thanks Tim

Thank you!!! simple to understand :)

Thanks a lot. Very Clear Examples.

Every word count, thank you so much

0:00 - Intro 3:16 - Creating and using extension method 8:15 - Extension method classes and namespaces 10:59 - Extending methods from third party libraries 19:48 - When to use extension methods 21:30 - Extending methods for interfaces 23:03 - When not to use extension methods 27:01 - Summary and concluding remarks

Two thumbs up!!

If you're not careful with extension method use, it can really make unit testing hard.

If you wanted to add features to a 3rd party library, wouldn't it make more sense to create something like a proxy to it and put the helper methods in the proxy instead? Dart supports extension methods too (seems like they are copying c# features or the other way around). Either way, I didn't stumble on a use case for them yet... I did see other people using them to share methods between classes. Don't know if that's a good use case though.

It is really helpful.

Tak!

Idea for next video topic: SharedProjects - what is it, when use it, pros/cons. Thank you.

what if you want to overwrite a value set by a parent in the extension class?

Thanks!

This could be handy for IEnumerable classes.

Excellent video, should have learned this sooner! For a future video, would it be possible to do more in depth mvvmcross videos? Thanks for all the great content, best teacher ever award!

I think that key word is "extension". Somethings not needed in my real program-flow. Is it right? 😉 But your lesson is landed right. .. ;) sorry for my english.

Your videos have been REALLY helpful. Thanks for everything you do! Question: will you be doing anything on TDD? I'm having trouble wrapping my head around it...mainly where and how to start. I'm about to start developing a new website for my work and am trying to wrap my head around TDD for it

Hi Tim. Would you consider it a good practice to implement serialization as extensions to model classes? You touched on it briefly in your video, but it occurred to me that implementing serialization as extension methods makes it easier to switch from say XML to JSON without having to touch the model class(es). You just have to write some new extension methods. Or is it a better way of implementing serialization?

ty

Hey Tim. What's your opinion in using PostSharp? For example, in logging. And AOP in general. Just going through a Clean Code C# book and it is implementing it to keep some code with DRY and SRP.

Please also make video on identity server4!!

Ok Tim, here's a challenge for a video. I always hit a speedbump when I'm working with timed loops, so here's a scenario. You have an API project using a SignalR Hub. Anyone can subscribe to your hub to get data over intervals, but you don't want a million queries to be triggered to your database. You settle on a timed loop that 1. Queries the database. 2. Activates your Hub to send messages to it's subscribers. You can use any type of data here... Stock Tickers, Sports Scores... doesn't matter. Architecturally, which timer would you implement, and how would you allow people to get message at custom intervals. Say their choices are to receive messages every 10, 20 and 30 seconds. Also, the loop shouldn't run unless at least one client is subscribed. That would make an interesting video I think.

ily.

I love extension methods because it makes code clean and readable. But I found that it's difficult to write tests against these extension methods since they are all static methods within a static class.( For instance, they cannot be mocked)

I extended DateTime to add a method that can calculate what we call here in Chile Working Days (Mon - Fri) since some stuff will take for example 10 Working Days, and i will like to know on which date those 10 working days will be done, also added an overload that will let you consider the current day as a working day. If any one wants it i can upload to my GitHub... any ways.. i will probably will be modifiying it so you can also pass an array of days you want to exclude from the calculations, lets say you know the 4th of July this year on on Tuesday, since it is not considered as a "working day" you can exclude it, but for now, that is just an idea! :)

Great video! I'm looking for somethings similar but for properties. Any way to do this in c#?

Hey Tim, Am I able to extend Form to add a property? I want Form to have a selectedItems property

Complex numbers class from Numerics does not have any Parse method "Prototypes" of this Parse methods can be public static Complex Parse(string? ) public static bool TryParse(string? out Complex) Can this methods be written as extension methods

It was really good. But all methods are void because of the logging operation doesn't need a return type.

Is mixing relevant in the world of C#? If so, can extension methods be used to achieve it?

Hi Tim, How about the performance of an extension method? how can we measure it?

This is great, now I can create an extension for TextBox that tells me if the text is empty. textbox.isEmpty() looks better than string.IsNullOrEmpty(textbox.Text.Trim())

Thanks Tim, are you able to put the link to the source code in the comments?

Tim have you ever done something on Merge Conflicts in VS?

It seems like visitor design pattern

The way you speak in this video in particular feels faster than usual or it's just me?

Yeah .. Oriented choose implements .

Thanks!