Thank you for the informative video, Nick. I would suggest that you should also do a video showing the advantages of Closures. Closures are not always bad and they can be very useful in certain situations.

Oh wow. Finding out about clrheap alone was totally worth watching the whole video. You did a good job explaining this and doing the walk through as well. Thanks for this.

Nice vid. That ClrHeapAllocationAnalyzer is a great tip. Thanks

Good preface on the video about premature optimisation. It's something as a newbie programmer I struggled with when 99% of my projects would never need high performance! And that 1% where performance was an issue, it's because of something much more simple than advanced topics. Still, I love seeing indepth looks into how C# works !

Learned something new today. Thanks for that!

I love c# very much and i like people who help us to improve our knowledge, thank you so much bro . still with us 🙏🙏😁😁

Beautiful video. Something I have never considered in all my years coding in c#

I am using Linq lambda expressions all the time and was not aware of closures. Even though my applications run fine, I might be able to optimize memory usage with that new knowledge. Thanks!

Very informative as usual. Thank you very much!

Thank you very much, Nick. Great job!

Great video Nick!

Awesome content. Very useful for coding on IOT devices.

Awesome tip. Thank you for sharing

Really nice explanation, tnx

I think another problem with this is, that from functional programming you learn that you should keep your functions as pure as possible (not influencing or being influenced from stuff outside the function). So a more correct lambda would be ...(x, number => x>number); //if that would even work it is So I wonder if that scenario would also allocate on the heap

There is also Heap Allocation Viewer in Rider plugin to catch closure and more when allocation is happening

nice video young chap!

This is the in-depth geekery that I live for.

How that function is being called when you have taken off the variable from arguments list?

Ωραίος φίλε Νίκο

This is kind of a bummer because the "fix" is to just make your code more low level and less readable. I wish it were optimized automatically.

Yep when you write such lambda closures in C++ you have to write what should be captured and how (e.g. by ref or value)

It is any way to avoid allocation in your example with passing argument in another method?

Hey Nick, you seem to be future Tim Corey Fantabulous!

Is there a way to pass an argument into the lands so it doesn't need the closure?

That "lexical" thing is really from the wikipedia article about closures and this is certainly not the first video from someone where I hear criticism on that. That article seems to have improved a bit compared to how bad it was earlier, but it's just crazilly complex explanation of something very simple. The feature is most well known from JavaScript, but C# can do the same thing indeed and C++ has even a very advanced implementation in which you can make very precise decisions about what variables you exactly want to capture from the scope around and how (pointer, referene, etc).

Another useful video Niko. Thank you. These things can blow out of proportion in an environment loaded with asynchronous calls. Also, const-ness is something I am really missing in C#, having had a (bitter-sweet) taste of C++ development. And I find that c# developers lack the consideration (or discipline?) to set things to const if they are such. They thing that it is an overkill.

I wonder why the outer scope of closure is passed in as a class instead of passing it via additional parameters to a callback

do you have another video on how to tackle this issue? Like imagine I still want it to keep number as a parameter and use delegates and get rid off closures, is that possible?

Nice vid and explanation. BTW, how long do you have to be a Patreon for before your name appears in the acknowledgments at the end? Mine isn't there.

Fun to see about a thousand warnings after installing that package xd

7:30 Why does it still allocate? Is it a LINQ internal allocation for some reason, or is it a language-level alloc?

I wonder if I make a field _savedNumber in class and put the number value to that field and use the field in lambda it would still allocates memory?

Yes, I'm into functional programming. How could you tell?

It's a boxing effect ? Compiler optimization will fix it ?

Hey Nick, what IDE are you using on the video?

What's the alternative?

Great Video, I enjoyed it very much, however I have a small question. When Reading the C# In Depth it struck me that Closures reminded me of Captured Variables. Am I wrong when I assumed that Captured Variables in C# is the same as Closures?

You should add a video about how this affects the new record type. I imagine that a class gets created to hold a copy of the record, but maybe its just a reference instead of a copy.

The real issue that closures can cause is that they can hold on to references, preventing the garbage collector from cleaning them up, in a similar way to event handlers. Also if you have more than one lambda in a method they can capture more than you might expect. A few bytes of memory here or there doesn't generally matter too much, but a lot of allocations means a lot of garbage collections, or a reference being kept can prevent a large tree from being collected. For example you might have a CancellationTokenSource with some references to CancellationTokenRegistrations, with closures that capture an object that contains a MemoryStream, which keeps a reference to it's full buffer even after being disposed. Of course the CTS and CTR are disposable, so make sure to dispose them for this particular case, but it's just one example.

Which IDE is that? vscode?

👍

What if you use readonly instead of const?

Hi, Nick...I have been watching your videos. Some of them are ready great. Thank you. Just a friendly suggestion, can you slow down half of notch, so I can better understand you? :)

Love your videos. Here's a video idea... I've been working with visual studio for years and never really learned how to read the intelisense documentation. I mean for most stuff it's no issue but i have trouble reading how to call Dictionary with linq or selectmany etc. I just either google these features or remember them. It'd be neat to be able to read the intelisense documentation

What if you use a larger object instead of an int? It seems like it keeps just the value of the int instead of a reference... for some reason?

Sounds like this display class issue can be solved by the compiler. Maybe force it on the stack with a record instead of a full class.

This is a lamda expression, or the arrow function. If you use some variable from the caller's scope, then it must be generated on the fly. It does not only consume more memory, but also consume more CPU because it has to be re-compiled, because each function is a different instance. This is a really a hidden perf killer. Some developers may not realize it when they write the "bad" code.

JavaScript: *sweating uncontrollably* (In js every function is a clusure)

Does visual studio have memory tab like in rider?

How can I see that 'Memory Window' using Visual Studio?

Does this significantly effect performance when the system has loads of RAM?

What IDE is that ?

Can somebody tell me, what is the IDE he works in?

C# keep surprizing me. I was expecting the compiler to do it for me. If i recall java lamda only allow "final" variables to avoid that...

closures are great, C#'s weak reference system is really sucks. I miss Swift 's weak-strong operators.

Been programming C# since forever. Watched the whole video. Still haven't got the foggiest idea what a closure is :P

Hair update 👀👍

You do realize it's always making a class, right? It doesn't get named with "Display" because it's not closing over a value, but it's still there as a Singleton.

Imagine chaining multiple LINQ calls

There are 2 types of people, Those who like closure.

Huh never seen someone use rider on any youtube video

numbers numbers.....mmh numbers ! lol XD

Shouldn't the function be called "NumberOfNumbersOverNumber"? 🤔

Братан, хорош, давай, давай, вперёд! Контент в кайф, можно ещё? Вообще красавчик! Можно вот этого вот почаще?

This is one of the more frustrating things about C#. A whole bunch of language features are needlessly rendered unusable for performance-critical code when the compiler could easily convert the .Count() method into a for loop with 0 allocations behind the scene.

An anonymous lambda is compiler syntactic sugar that is meant to reduce the amount of code you have to write....the compiler will expand it for you (which could include inserting classes and methods). Solution....don't rely on compiler syntactic sugar and just write the code yourself.

Audio/video out of sync

There is never anything that makes your life easier, that does not have a cost in performance. Every shortcut, has it's price. People need to get this on their heads. :-\ Lazy coding, will always cost you something. :)

The more videos I watch about C# optimization, the more I think LINQ is just a bad idea. There are so many pitfalls and gotchas.

What's the point? It makes no difference in real life anyway.

I like your videos but this one is so boaring , i could not end it