Writing about learning C#, moving into software, and working with .NET. Specific, and without promising a job in three weeks.https://devjourney.app/en-ushttps://devjourney.app/en/dotnet/blog/ef-core-n-plus-one/https://devjourney.app/en/dotnet/blog/ef-core-n-plus-one/A report loop that looks harmless sends a separate SELECT per customer through lazy loading. Real SQL logs, timings at three data sizes, and two fixes.Mon, 26 Oct 2026 00:00:00 GMTef-coredotnetbledyArtur Kothttps://devjourney.app/en/dotnet/blog/first-unit-tests-csharp/https://devjourney.app/en/dotnet/blog/first-unit-tests-csharp/Your first xUnit test doesn't prove the code works, it forces you to say what working is. Real dotnet test output, green and red, and how to read both.Mon, 19 Oct 2026 00:00:00 GMTtestowaniecsharpnarzedziaArtur Kothttps://devjourney.app/en/dotnet/blog/learning-to-code-in-the-ai-era/https://devjourney.app/en/dotnet/blog/learning-to-code-in-the-ai-era/Two models got the same prompt and both returned C# that compiles. One of them is wrong in 55 cases out of 2349 and never raises an error about it.Tue, 06 Oct 2026 00:00:00 GMTainaukakarieraArtur Kothttps://devjourney.app/en/dotnet/blog/bootcamp-vs-self-study/https://devjourney.app/en/dotnet/blog/bootcamp-vs-self-study/One US bootcamp charges the same for its classroom and its mostly self-study schedule. The price follows deadlines and people, not the material.Tue, 29 Sep 2026 00:00:00 GMTprzebranzowieniekarieranaukaArtur Kothttps://devjourney.app/en/dotnet/blog/nullreferenceexception-explained/https://devjourney.app/en/dotnet/blog/nullreferenceexception-explained/FormatReceiptLine used a null customer. FindCustomer, the method that created that null, already returned and isn't even in the stack trace.Mon, 21 Sep 2026 00:00:00 GMTcsharpbledydebugowaniepodstawyArtur Kothttps://devjourney.app/en/dotnet/blog/first-minimal-api/https://devjourney.app/en/dotnet/blog/first-minimal-api/Four route mappings in one Program.cs produce a working HTTP server. Real responses, real headers, and the two mistakes you'll hit on your first POST.Mon, 14 Sep 2026 00:00:00 GMTaspnetdotnetnarzedziaArtur Kothttps://devjourney.app/en/dotnet/blog/debugger-vs-print-debugging/https://devjourney.app/en/dotnet/blog/debugger-vs-print-debugging/Adding one Console.WriteLine and re-running costs over six seconds, measured. One breakpoint stop hands you seven variables without touching the file.Wed, 02 Sep 2026 00:00:00 GMTcsharpdebugowanienarzedziaArtur Kothttps://devjourney.app/en/dotnet/blog/install-dotnet-sdk-first-program/https://devjourney.app/en/dotnet/blog/install-dotnet-sdk-first-program/The installer asks you nothing and takes a few minutes. The time goes into checking that the version answering your terminal is the one you think it is.Tue, 25 Aug 2026 00:00:00 GMTdotnetnarzedziapodstawyArtur Kothttps://devjourney.app/en/dotnet/blog/cs0029-implicit-conversion/https://devjourney.app/en/dotnet/blog/cs0029-implicit-conversion/The compiler is not asking for a cast. It is telling you no route exists between these two types, and a different number covers the case where one does.Mon, 17 Aug 2026 00:00:00 GMTcsharpbledypodstawyArtur Kothttps://devjourney.app/en/dotnet/blog/career-change-to-programming/https://devjourney.app/en/dotnet/blog/career-change-to-programming/It doesn't start with picking a language. It starts with an honest hours audit, three real schedules, and the arithmetic of what a quarter buys you.Fri, 07 Aug 2026 00:00:00 GMTprzebranzowieniekarieranaukaArtur Kothttps://devjourney.app/en/dotnet/blog/csharp-or-java-first/https://devjourney.app/en/dotnet/blog/csharp-or-java-first/Both languages have a real junior market. The difference that matters is how long it takes before you have something running that you can show someone.Mon, 03 Aug 2026 00:00:00 GMTcsharpprzebranzowieniekarieraArtur Kot