As every year, the dotnet team adjusted the runtime and libraries to improve performance. So let's go over some of the highlights. I will link the corresponding blog post or GitHub issue for each item, so you can read more about it if you are interested.

And of course: You will find the benchmarks at the end of the article.

Read the whole article

If we have a List<T> and an IList<T>, enumerating over the List<T> is faster than enumerating over the IList<T>. Why is that?

Read the whole article

In C# we have many nice guards sitting on top of static exceptions classes like ArgumentNullException, ArgumentOutOfRangeException, etc: As ArgumentException.ThrowIfNullOrEmpty, ArgumentException.ThrowIfNullOrWhiteSpace. Now we can extend them easily!

Read the whole article

New dotnet version means new features and improvements. There is a nice update to the HttpClient class in .NET 10.

Read the whole article

Sometimes you want to have a custom 404 page - and since .NET 8 and "Blazor WebApps" the <NotFound> tag of the Router doesn't work anymore, so let's create a custom page for that.

Read the whole article

Tailwind version 4 was just released. With the new CLI, it is just so much easier to use tailwindcss with Blazor. So in this post, I will show you how to use the new CLI to create a new Blazor project with Tailwind v4.

Short disclaimer: If you still want to use version 3, I already wrote an article about this some time ago: "Blazor with TailwindCSS".

Read the whole article

A contributor for this blog was recently filing a Pull Request to support Postgres. As I didn't want to run that thing locally to test, I needed a cloud service. That is why I tried neon.

Read the whole article

The .NET provided DI container has some means to check if the container can be created. This is useful to ensure that all dependencies can be resolved and that the container is correctly configured. Let's have a quick look.

Read the whole article

Almost all applications are using CORS (Cross-Origin Resource Sharing) to allow the client to access the resources from the server. When the client sends a request to the server, the server will respond with the Access-Control-Allow-Origin header to allow the client to access the resources.

Read the whole article

Debugging is important, and it's often useful to be able to inspect the state of objects in the debugger. However sometimes you're working with 3rd party types that don't have any debugging capabilities, so you can't see their internal state easily. In this blog post we will have a look on how to equip 3rd party types with debugging capabilities.

Read the whole article

LINQ has a Join operator, that basically translates to something like a SQL INNER JOIN. There is no built in operator for a LEFT JOIN in LINQ, but you can achieve the same result by using a combination of GroupJoin, SelectMany and DefaultIfEmpty. But there is a chance that this might change in the future, as there is a proposal to add a LeftJoin operator in .net 10.

Read the whole article

Ahhhh dear LinkedIn - a pool of gems where everyone is expert in everything. Over the time I collected some trophies from there and today I want to discuss one of them: "Always use early returns".

Read the whole article

Today, we are going to benchmark the performance of the Minimal API in ASP.NET 9 (and for reference against ASP.NET 8 as well) against the classic Controllers. We will test a few scenarios and check how the performance of the Minimal API compares to the classic Controllers. Let's get right into it!

Read the whole article

Join us for an exciting seminar with Fabian Gosebrink about .NET 8, Nx, and Angular! Learn the latest trends and best practices. More details: here

Read the whole article

I came across a very annoying "issue" with LINQ joins (left joins) in Entity Framework where the compiler drove me nuts!

Read the whole article

I recently came across the FormattableStringFactory to create dynamic FormattableString instances. This is a very useful feature in combination with safe SQL queries and the SqlQuery method of Entity Framework Core.

Read the whole article

Even though it was introduced in .NET 7, I came across recently the AsParametersAttribute. Let's have a look what it is good for.

Read the whole article

You often here that the async/await keywords leads to a state machine. But what does that mean? Let's discuss this with a simple example.

Read the whole article

.NET natively knows UUID v4 aka Guid.NewGuid(). But with preview 7 we get Version 7 of UUID's natively.

Read the whole article

The next preview (preview 6) will bring a new type ReadOnlySet<T>. This is a read-only set that is similar to ReadOnlyCollection<T>. Let's see how it works and why it was introduced.

Read the whole article

Have you ever asked yourself if your EF LINQ queries are susceptible to SQL injection attacks? Either because you are querying some user data from a text field or directly taking whatever your API hits against the database?

Read the whole article

The StringBuilder class is used to create mutable sequences of characters. Strings are immutable, so if you need to perform multiple operations on a string, it is better to use a StringBuilder instead of a string. This is especially useful when you need to concatenate a large number of strings. But there is more magic to it, especially when we go BIG!

Read the whole article

I made a memory dump in my simplest console application and there are a bunch of exception instances around, what is going on? Let’s see in this blog post, why you see a few exception instances in your memory dump.

Read the whole article

Http files are nice and handy - but they are also a bit of a pain to update. So why not generate them from a swagger definition?

Read the whole article

I am a big fan of Analyzers, and in this blog post, I will showcase some of my favorite ones!

Read the whole article

Everyone falls for that and tries to change a list while enumerating it greeted by the System.InvalidOperationException: Collection was modified; enumeration operation may not execute. message. But how does the List know that you changed it? Let's find out.

Read the whole article

Sometimes, you have multiple async calls to make, and you want to do that asynchronously and get the results afterward. Let's build a fluent API to do that.

Read the whole article

Pattern matching is a powerful feature in C#. It allows you to match a value against a pattern and extract information from the value. The compiler does the magic for you - and sometimes it struckles with that.

Read the whole article

Hangfire/Quartz or BackgroundService? Why not something in the middle? Did you ask yourself this question from time to time? Do you want to have a full-blown job scheduler with lots of setups, but more than BackgroundService is needed?

Meet: NCronJob!

Read the whole article

I recently discovered this small but very useful utility in xUnit: TheoryData<T>.

Read the whole article

Boolean parameters are nice, but it's hard to keep track of what each one does when you have multiple of them. In this blog post, we will see why it's better to avoid multiple boolean parameters and how to refactor them.

Read the whole article

In this blog post, a small and (over)simplified infographic on how the Garbage Collector works.

Read the whole article

Even though we are in the alpha of .NET 9 and .NET 8 was released not more than two months ago, the dotnet team does not sleep and pushes new changes! In this blog post, we are checking what new methods were added to everyones favorite: LINQ.

Read the whole article

I am not the biggest fan of AutoMapper. It starts with good intentions but often ends up being a big mess. I have seen it used in many projects, and the configuration of the mappings is often scattered all over the place, and or they are huge!

Read the whole article

In this blog post, I showcase a very simple lock-free ring buffer for logging. I'll show why it's useful and how it works.

Read the whole article

Only one month after the big release of .NET 8, the dotnet team is already working on the next iteration: .NET 9. With that also comes new language features. The first one is about to be merged into the main development branch: Params Collections.

Read the whole article

This blog post describes my journey writing a new interceptor for .NET 8. This is not meant as a general tutorial, even though I will showcase some of the code samples.

Read the whole article

The latest version of the .NET (version 8) has introduced a "better" way of logging. This new way of logging is more flexible and enhanced than the previous versions. It is about the LoggerMessageAttribute.

Read the whole article

In this article we will create a class, aka a reference type on the stack, and therefore don't use any managed memory!

Read the whole article

Ever wondered how to use TailwindCSS with Blazor? Let's make it work!

Read the whole article

This blog post is a small collection of questions I asked as a technical interviewer when we had candidates for software developer positions. This might be helpful for you if you are preparing for a job interview.

Read the whole article

In this article, we will build a minimal version of what ASP.NET Core does - yes, you read right. We will create a very simplistic clone of ASP.NET Core to discuss how the whole thing works. Beginning with a simple console application, we will add the necessary components to make it work as a web server. Bonus points for our own middleware pipeline and dependency injection.

Read the whole article

Since C# 8, we have nullable reference types. The word sounds odd, given the fact that reference types are always nullable. The idea is that the default is that your reference types have to be properly initialized. Here are my thoughts after a few years of using them.

Read the whole article

Are these two expressions the same?

public class MyClass
{
    public int A { get; } = Random.Shared.Next(1000);
    public int B => Random.Shared.Next(1000);
}

Read the whole article

With respect to the current topic around Moq, I want to showcase how you can easily roll out your own fakes so that you are not depending on a third party library.¨

Read the whole article

The .NET 8 preview 7 will bring another exciting feature some of you probably awaiting for a long time: Keyed services.

Read the whole article

With the famous BenchmarkDotNet library you can benchmark a lot - but it doesn't stop with a single .NET version. You can benchmark multiple versions of the same code that targets different runtimes!

Read the whole article

I was recently tasked to migrate an application with around 150 projects from the "old"^{It is still supported} .NET Framework 4.8 to a recent .NET 6. As the application is still under development and used, the migration should be done step by step over time in iterative steps rather than a big bang refactoring. This blog post will go a bit into more detail about how I approached the situation and what I learned.

This is a highly subjective post, and there are plenty of ways of approaching it - so take it with a grain of salt and mileage may vary.

Read the whole article

On a recent LinkedIn Post from Saeed Esmaeelinejad, he asked what is the outcome of:

bool flag = SomeMethod();

M(flag ? 1 : 2);

void M(long number) => Console.WriteLine("long");
void M(short number) => Console.WriteLine("short");

What is the outcome?

Read the whole article

LINQ is a very powerful tool for querying data. As the majority of functions are built on top of IEnumerable<T> and it, in most cases returns IEnumerable<T> as well, it is very easy to chain multiple functions together. That leaves you with a question: which one should I use, Select.Where or Where.Select?

Read the whole article

In this blog post, I'll show you the fundamentals of the Mediator pattern and how to implement it in your application from scratch. And yes, we basically implement the famous MediatR library.

Read the whole article

There are many different memory types used in modern C# programs. The more common ones are Span<T> and Memory<T>. Occasionally there is also ReadOnlySequence<T>. What do these types do?

Read the whole article

With preview 4 of .NET 8, a new terminal logger was introduced. It basically removes a lot of the noise that the default logger produces. It also adds some nice colors to the output. Let's see how to use it!

Read the whole article

TryGetNonEnumeratedCount attempts to determine the number of elements in a sequence without forcing an enumeration. It returns true if it could and false if it couldn't. The API was added with .NET 6 - let's have a look at how that thing works.

Read the whole article

In this blog post, we will explore some cool things you can do with ValueTuple. Also, a short explanation of what ValueTuple is and how it works.

Read the whole article

In this blog post, we will have a look at the different log levels and how to control them.

Read the whole article

In this small blog post, I will show you how to create your own Validation attribute in ASP.NET Core to tailor-made your validation rules.

Read the whole article

Let's talk about Contravariance and Covariance in C# using .NET Framework examples!

Contravariance and covariance are essential concepts in C# when dealing with generics, enabling us to have more flexibility when assigning generic types. So let's have examples straight from the framework itself!

Also, we will go a bit deeper and talk what some differences between generic constraints and things like Contravariance are.

Read the whole article

In this short blog post, I will show you 5 useful extensions for Task in .NET. We will build them as extension methods, so there are easy to use. On top, I will show a small example of how to use them. So let's go!

Read the whole article

In this blog post, we will explore the use of SIMD instructions to speed up LINQ queries. We will use the Vector type of performing SIMD operations on arrays of data. We will also use the BenchmarkDotNet library to measure the performance of our code. We will also see how this works hand in hand with the new "generic math" feature of C# 10.

Read the whole article

Source generators are a powerful feature introduced to C#, allowing developers to generate additional code during the compilation process automatically. They can help reduce boilerplate, improve performance, and simplify your codebase.

This blog post will introduce source generators, discuss how they work, and walk through an example of a source generator for generating build information.

Read the whole article

In this blog post, we will discuss how we can "cache" entries from the database. We will talk about why we would do this in the first place and how to achieve that.

Also, we will talk about some implications and what "cache invalidation" is.

Read the whole article

Skip and Take are used for pagination or limit the number of elements returned by a query.

Since C# 8 you can use Take with a Range. Let's see some examples.

Read the whole article

In recent months and years, there was a certain hype around benchmarking, also in the .NET community.

This blog post is meant to ground some of the benchmarking topics and put this into relation to other things so you get a better understanding if it's worth the effort.

Read the whole article

The Humble Object Pattern is a design pattern to make especially unit testing easier with the goal of separating behaviors that are easy to handle (domain logic) from behaviors that are hard to handle (like external events or dependencies).

So let's have a look at what it is and how you can utilize it.

Read the whole article

In this article, we will discuss the testing pyramid - what it is and what are some problems with that.

We will also discuss a different approach: The testing diamond.

Read the whole article

Did you see the following error in recent days in your build-pipeline:

error NETSDK1194: The "--output" option isn't supported when building a solution.

If so - that is not necessarily your fault at all! Microsoft released a new SDK version, which breaks your builds. Let's see why and what we can do to tackle that.

Read the whole article

Did you ever ask yourself: What is a middleware, and why should I use it?

If so, this blog post is exactly for you. We will see where we could use a middleware and also how we can use the Dependecy Injection container of ASP.NET Core.

Read the whole article

In this blog post, we'll dive into the ins and outs of the repository pattern and examine both its benefits and its potential drawbacks. We will start from the very basic to some more advanced use cases. So let's dive right into it.

Read the whole article

... if you need more than 3 levels of indentation, you're screwed anyway, and should fix your program.

This is written in the Linux style guide. Let's see why they have that rule and how we can overcome deeply nested code.

Read the whole article

Cohesion represents the degree to which the elements of a module belong together. A module or class is said to be highly cohesive if its methods and data are highly related, meaning that a change in one affects just a small number of elements.

We can use this metric to know whether or not an object is in a good shape or needs some refactoring.

Read the whole article

I often read that Task is used for multithreading in C# / .NET, but that is not the case. And it is crucial to understand why this isn't the case. We will also see which problem exactly Task is solving in the first place.

Read the whole article

Strings are one of the most universal data types. We use them for URLs or regular expressions or even to define some date. With .NET 7 we have a new way of giving those strings a bit of meaning. Meet StringSyntaxAttribute.

I also show you a way how to use them in .NET 6 and earlier.

Read the whole article

Many know that you can take ReadOnlySpan<char> objects when dealing with strings. They give you a direct way of operating on the underlying memory. Often times you can use them interchangeably, but there are scenarios where you really have to watch out what is going on.

This blog post will have a look at a major problem with ReadOnlySpan when used like a "regular" string.

Read the whole article

.NET knows a big list of collection-like types like: IEnumerable, IQueryable, IList, ICollection, Array, ISet, ImmutableArray, ReadOnlyCollection, ReadOnlyList, and many more.

This blog post will give you an exhaustive list of types in .NET and when to use what.

Read the whole article

Sometimes you have an Id of an object and want to delete the underlying thing from the database. But it doesn't make sense to load the whole object from the database to memory first. So how can we achieve this quickly?

Read the whole article

In the past, it was tricky to get if the current process runs under elevated rights. In the sense of it is run under the sudo group in *nix (Unix, Linux, macOS, you name it) or administrative rights in Windows.

But that changes with .NET 8 as we now have a unified API for that.

Read the whole article

Did you ever wonder how we can iterate through a StringBuilder? I mean, of course, we can just call ToString and use the returned string, but that means we materialize the whole thing without good reason.

We can also use a normal for-loop. But we can also find a completely different and probably dumber way! And if you wonder: No, this is not something you do in your daily life, but by doing so, I can show some cool stuff C# and .NET offer.

Read the whole article

Analyzers did become an integral part of the .NET ecosystem. Their main responsibility is to find potential code issues and warn you. Often times this comes even with potential fixes you can directly apply.

And Microsoft will continue this journey with the upcoming .NET 8 release. This blog post will show you potential candidates, which will make the cut.

Read the whole article

Use always a StringBuilder

That is what you can read from time to time. The basic idea is, that a StringBuilder is "better" ^{to be defined}.

Why are people telling that ^lie? Let's discuss this and see what it isn't true.

Read the whole article

Often times we have unit or integration tests that rely on some input data. The easiest solution is just to take some hard-coded values and move on with life. This has some major downsides:

Giving specific values in a test carries meaning, but we are often times not interested in that. We just need to pass the object around to fulfill the API. Also the simplest solution to fulfill your test is literally checking against those values.

Here is an elegant solution to that problem: AutoFixture. I will show you what it can do, especially in combination with xUnit.

Read the whole article

Often times your API in your program or library evolves. So you will need a mechanism of telling that a specific API (an interface or just a simple method call) is obsolete and might be not there anymore in the next major version.

Also it can happen that you have a preview version of a API, which might not be rock-stable and the API-surface might change. How do we indicate that to the user?

Read the whole article

.NET knows local functions and lambda expressions. You can almost take them interchangeably, but there are also some differences between them.

This article will show the differences between them.

Read the whole article

In this article we will have a closer look at LiteDB, a .NET NoSQL Document Store in a single data file. We will discover the advantages of LiteDB and why it is a viable candidate for your next project.

We will also explore what are the differences between a NoSQL and a classical SQL database are and what this has to do with the reminiscent SQL CE or the more modern SQLite database.

Read the whole article

This edition has the following infographics:

• ConfigureAwait on IAsyncDisposable
• Index in foreach
• Non-destructive mutations with struct
• Returning null for a Task
• Throw-Helper
• verbatim strings

Read the whole article

Sometimes I publish parts of my infographics I publish on various channels with more explanation.

And then sometimes I don't. This time I just put some of my (hopefully self-explanatory) infographics here.

• Pure functions
• Generator functions
• Cost of anonymous types

Read the whole article

Pattern matching, which was introduced in C# 9, is a hell of a beast and does more than you might think.

In this small blog post I show you where the magic is and what it does under the hood.

Read the whole article

This is a small story about how memory operates in your .NET application. Well not only .NET but how memory does or does not get allocated.

We will see how a 1 Gigabyte big array is only a few megabytes big to some extend. Furthermore I will discuss working set and committed memory.

Read the whole article

Often times it is easier to have a nice illustration at hand, which explains you things the easy way. So let's do this for a lot of LINQ operations like Where, Select and friends.

Of course a small explanation will be attached as well.

Read the whole article

When you get started or even if you have quite some knowledge it can be confusing to juggle with those terms. So what is the difference between C# and .NET? And what does it have to do with IL and JIT?

Read the whole article

I already made a post about how the Garbage Collector works in .NET and also introduced the topic of Generation slightly. This article will look a bit more in detail into why we have those mechanisms in the first place, including the Large Object Heap.

Read the whole article

RavenDB is a well known open-source document-oriented databse for .NET. And of course we want to test our logic and not only locally while developing, but also our continuous integration pipeline should be able to run our tests. So let's tackle exactly that.

Read the whole article

What is Tail-Recursion? We will discover this "special" form of recursion on the example of the Fibonacci series. Also we will check how much faster it is and why.

Read the whole article

When we are passing objects around we can do this either via reference or by value. Which of those two methods is faster?

To answer this question we have to dive into a bit of info about what happens exactly when you pass something around and how the other side will receive this.

Read the whole article

.NET brings two types which seem very similiar

• IEnumerable
• IQueryable

What is the difference? Most are familiar with using IQueryable when we want to go to the database and back. But why not using IEnumerable?

Read the whole article