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by Jiří {x2} Činčura

Throwing null literal

19 Sep 2019 C#

“Every” week I discover something new (and I’m not afraid to share it). Today isn’t any different. Apparently, C# compiler is fine with code throwing null literal. Yes, it looks weird, but if you think about it, it makes sense. Let me show you.

The code below compiles fine and results in NullReferenceException being thrown.

static void Test1()
{
	throw null;
}

I don’t know about you, but this, if not weird, looks funny. The NullReferenceException thrown isn’t anything special and you can catch it is as usual.

static void Test2()
{
	try
	{
		throw null;
	}
	catch (NullReferenceException ex)
	{
		Console.WriteLine(ex.ToString());
	}
}

So why is throw null even allowed? It looks like a special case, to be disallowed, but it’s not. Following simple code is absolutely acceptable.

static void Test3()
{
	Exception GetMeException() => DateTime.Now.DayOfWeek == DayOfWeek.Thursday ? null : new InvalidOperationException();

	throw GetMeException();
}

Basically “sometimes” my code returns null and that is then thrown. Discussion whether that is a bug or not is another discussion.

When I first saw (and it was in reference assemblies) the throw null I was perplexed. But trying it and then thinking about it in broader context, I realized it’s just a valid (but pretty stupid, don’t do it) code stripped to absolute minimum.

Update (based on comment below)

This, exactly, is part of the specification.

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WUG Days 2019

12 Sep 2019 .NET, .NET Core, C#, Multithreading/Parallelism/Asynchronous/Concurrency, Presentations & Speaking

Už se jen dvakrát vyspíme a bude tu další ročník WUG Days (14.-15.9.).

Hlasováním a odborným výběrem byla vybrána 4 😮 moje témata.

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Convenient method for explicit lazy loading in Entity Framework Core (or Entity Framework 6)

2 Sep 2019 Entity Framework, Entity Framework Core

Last week I was explaining explicit lazy loading on Entity Framework Core and quite understandably the question came about shortening/encapsulating the code, because you might need to use it a lot in some cases. It’s possible and luckily the method can also benefit from overload resolution in C# to handle reference and collection navigation properties transparently.

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Entity Framework Core’s ultimate escape hatch

14 Aug 2019 Entity Framework, Entity Framework Core

In 2007 then Principal Software Architect on Data Programmability team Mike Pizzo wrote in a “random” forum reply about Entity Framework’s DefiningQuery being the “ultimate escape hatch”. This was later mentioned in Julia Lerman’s famous book Programming Entity Framework. Just to make sure you understand this archeology (and yes, I spent quite some time digging the reply back – kudos to MSDN forum people keeping it still running), Entity Framework (the first version) was released in 2008.

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Friday’s This<T>

25 Jul 2019 C#

Last week on Friday I was working on some code, I don’t even remember what it was, and there was excessive usage of this. And my personal pet peeve is writing most readable code in most succinct way possible. For sure this hurts this (no pun intended). The following class is a result of that Friday’s frustration.

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Introducing D.ebug

10 Jul 2019 .NET, .NET Core, Debugging

Lately I’ve been doing a lot of debugging often in code that needs to be executed certain way, from certain place and sometimes is also modified post-build a little. And sometimes more stuff, which I’ll not bother you with. And this makes debugging a tiny bit more difficult.

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Empty try with finally

10 Jun 2019 .NET, .NET Core, C#

The finally block has a little unknown feature, that frankly isn’t even remotely needed for regular day-to-day development, but you already know content on this blog is usually little geeky.

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Comparing speed of Blob Storage, AppService and CDN on Azure for static file serving

30 Apr 2019 AppService, Azure, Azure Storage, CDN, Cloud

For no particular reason and with no particular goal I decided to see how “fast” some selected services, with the ability to serve a static file, on Azure are. I was interested in the time to serve the file and requests per second. The services I selected are AppService in B1 and S1 plan, Blob Storage GPv2 and CDN in Standard plan from Verizon and Microsoft.

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Global Azure Bootcamp 2019

20 Apr 2019 Azure, Azure Cosmos DB, Presentations & Speaking

Global Azure Bootcamp 2019. Jeden den, Azure po celém světě. A taky v Praze. I já přispěju svojí troškou do mlýna a povím vám něco o Azure Cosmos DB.

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Gopas TechEd 2019

10 Apr 2019 Presentations & Speaking

Web ještě nehlásí vyprodáno, takže je stále možnost urvat vstup. Na letošní TechEd jsem připravil tři přednášky:

  • .NET Core 3.0, .NET Framework 4.8 a proč vše kolem je největší změna od zrodu .NETu
  • Jak měřit výkon .NET kódu správně
  • Entity Framework vs. SQL Server – co jste mohli udělat a neudělali; a co jste dělat neměli a přesto udělali

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ADO.NET provider 6.6.0.0 for Firebird is ready

1 Apr 2019 .NET, C#, Databases in general, Entity Framework, Entity SQL, Firebird, LINQ, SQL, Visual Studio

New version 6.6.0.0 of ADO.NET provider for Firebird is ready for download. This release fills all the holes in the Entity Framework Core support. To be precise now Migrations are fully supported and query pipeline has been massively improved. Just to give you an idea, about 4100 tests were added. If you want to use Entity Framework Core with Firebird, now is the time.

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ThreadPool.QueueUserWorkItem has a generic overload (and a new parameter)

24 Jan 2019 .NET Core, .NET Standard, Multithreading/Parallelism/Asynchronous/Concurrency

Although nowadays people, including me, are working mostly with tasks and async/await, sometimes going one level lower is helpful, because there’s less to worry about. And as I was today calling trusty ThreadPool.QueueUserWorkItem I found new overload. Overload that is generic.

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G2B•TechEd 2019 a ShowIT 2019

20 Jan 2019 Presentations & Speaking

Za několik málo týdnů se konají opět konference G2B•TechEd v Brně a ShowIT v Bratislavě. V Brně budu mít dvě přednášky a sice Developer Keynote aneb .NET Core 3.0 a proč je to největší změna od zrodu .NET Core a Lua pro C# vývojáře a proč by se mi to mohlo hodit a V Bratislavě pak .NET Core 3.0 a proč je to největší změna od zrodu .NET Core a Přehled výkonnostních vylepšení v .NET Core a proč je určitě chcete.

Ať už v tom či onom městě vás zvu a rád zodpovím vaše případné dotazy.

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DotNET Talks, vol.2

17 Jan 2019 C#, Presentations & Speaking

Ups. Úplně jsem zapomněl na druhou edici DotNET Talks. Akce se koná dneska, tedy máte ještě půl dne udělat si čas. 😃 Já vám řeknu něco o tom co čekat od C# 8 v “Co čekat v C# 8.0 v kostce”. Podle webu ještě místa jsou, tak přijďte.

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Exploring C#’s ref return to better understand it

5 Dec 2018 .NET, .NET Core, C#, Roslyn, RyuJIT

I felt a bit fuzzy on the topic of ref returns in C#. I used it intuitively few times, but it felt I needed to fill some gaps and play with it in a little bit more structured way. This is my exploration of the topic. No particular order. No deep explanations. Just my thinking what should work and what not and trying it.

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Vertikální půlkilometr na schodech

5 Nov 2018 Running

Dostali jsme s Davidem Gešvindrem takový “zajímavý” nápad. V budově Gopasu v Praze je docela dost pater a po obědě, v rámci lepšího trávení a protažení, chodíme nahoru po schodech. Ve skutečnosti jdeme většinou z -2. až do 11. patra pro extra body. 😃 No a co třeba zkusit chodit nahoru a dolů…

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ICTech Day

5 Nov 2018 Multithreading/Parallelism/Asynchronous/Concurrency, Presentations & Speaking

I almost forgot to tell you about this. This week, Thursday, I’m speaking at ICTech Day in Belgium. And about the topics I’m very passionate about. First session is “Tasks and Await from the ground up” and other is “Async and Await”. If you’re in the area, maybe you can still try to make time and come (you have to be a guest of somebody from PeopleWare or Elmos).

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MonkeyFest Bootcamp Prague 2018

4 Nov 2018 C#, Presentations & Speaking, Xamarin

Za necelý týden se koná akce s názvem MonkeyFest Bootcamp Prague 2018, což je podobně jako Global Azure Bootcamp akce konající se v jeden den na celém světě. MonkeyFest je zaměřen na svět Xamarinu a příbuzných technologií. No a protože Xamarin je také o C#, připravil jsem si přednášku s názvem “Co čekat od C# 7, 7.1, 7.2, 7.3 a 8.0”. Pokud vás novinky C# zajímají, nezapomeňte dorazit.

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Comparing speed of ToUpper, ToUpperInvariant, ToLower and ToLowerInvariant in .NET Framework and .NET Core

23 Oct 2018 .NET, .NET Core, JIT, RyuJIT

While I was reviewing some code week or two back, I got idea to test what’s the speed difference between ToUpper, ToUpperInvariant, ToLower and ToLowerInvariant. Of course, these methods are not doing the same thing, but sometimes it doesn’t really matter and if any is sufficient then, maybe, performance wins. Or at least I thought it’s going to be interesting to see whether there’s a difference and how much.

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WUG: C# 7, 7.1, 7.2, 7.3 a 8.0 (Zlín)

18 Oct 2018 C#, Presentations & Speaking

Máte rádi C#? A ztrácíte se v aktuální rychlé kadenci verzí? Mám pro vás řešení – WUG 25.10.2018 od 17:30 ve Zlíně. Všechno dáme do kupy a srovnáme si to v hlavě.

C# v poslední době velmi rychle přidává nové funkce. Malé funkce v minor verzích, ale připravuji se i velké změny do major verze (verzí). Co je tedy dostupné v C# 7, 7.1, 7.2, 7.3 a jak to začít používat. A co nás čeká dál a hlavně ve verzi 8.0?

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WUG: Asynchrónne a paralelné programovanie v .NET-e (Košice)

3 Oct 2018 Presentations & Speaking

Tak to vypadá, že se podívám do Košic. Na WUGu si povíme něco o asynchronních a parallelních věcech a jak to celé do sebe zapadá a co je “pod tím”.

Naposledy jsem tam byl na maratonu v roce 2012 a poměrně dobře si pamatuju segment 30. – 35. km. “Lehce” 😃 jsem potkal “zeď”. Naštestí jsem to do cíle “dotlačil”. Tak snad WUG zvládnu lépe. 😃 Určitě přijďte.

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DotNET Talks, vol.1

30 Sep 2018 Entity Framework Core, Presentations & Speaking

Už příští týden se uskuteční nová akce s názvem DotNET Talks. Moje přednáška “Unit Testing s Entity Framework Core” se podívá na to jak “unit” testovat kód, který využívá Entity Framework Core. Díky “čerstvosti” Entity Frameworku Core jsou možnosti o poznání lepší než tomu bylo u Entity Frameworku 6. Jak to vypadá, tak ještě pár míst můžete urvat, tak neváhejte…

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Step into a specific call when debugging in Visual Studio

24 Sep 2018 Keyboard, Visual Studio

Last week, as we were wrapping the first day of .NET Developer Days conference, I was sitting in the “Ask The Expert” area quietly by myself, reading the poems, waiting for questions with Kendra Havens chatting about Visual Studio shortcuts and enjoying the pre-party beer. As it turned out, there’s one super handy shortcut for debugging that most people – Kendra included 😉 – are not aware of (and which I wasn’t able to cover in my 60 minutes of allotted time). Thus, I must spread the word.

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