Like many .NET developers, I’m starting to look at the features coming in .NET 10, C# 14, and specifically ASP.NET Core. To my surprise, ASP.NET Core Minimal APIs now support Server-Sent Events (SSE). For folks who don’t know what Server-Sent Events are, they are a unidirectional channel from the server to a client where a client can subscribe to events. SSE is handy for building live news feeds, stock ticker applications, or any system that has real-time information.

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Every couple of years, I tend to write the same variation of an enum helper that reads metadata from an enumeration using reflection. Almost any .NET developer with a few years of experience has done the same. The implementation uses Generics to work for any enum defined in my solution, as there is typically more than one described in a typical .NET solution. Historically, generics and enums didn’t work well because of the limitations of generics when dealing with this particular type, but to my surprise, they do now!

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Every development career has milestone moments. One we all likely share is building a custom content management system, or CMS, as developers like to refer to it. A common approach to melding metadata and content is utilizing the old reliable Markdown format, which fuses YAML frontmatter with a simple content format. While YAML is flexible, it can be less than ideal when wanting to use that embedded data in your ASP.NET Core applications.

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I was recently looking at the Duende Software codebase, and I kept seeing the same suggestion offered by the IDE tooling whenever I encountered a ConcurrentDictionary: “Closure can be eliminated: method has overload to avoid closure creation.”

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If you’ve spent time around web development or your grocery store’s baked goods aisle, you’ve probably dealt with cookies. Let’s discuss the web kind today. A cookie is a header key-value pair that is set on the server using the Set-Cookie key, and a value of <name>=<value>. Cookies persist on the client, where the client will send each cookie to the server on each subsequent request. It’s a simple way to persist state in the stateless web environment and avoid complex session management infrastructure. That said, cookies have limitations, mainly the 4kb size limit for each unique cookie. Size limits can be a serious problem for ASP.NET Core applications, which rely heavily on maintaining user session data in an encrypted and encoded cookie.

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When it comes to programming, correctness is the name of the game. Every developer aims to understand, model, and limit potential outliers when executing code because those unknown variables can lead to exceptions and critical failures. There are many techniques developers use, but I recently discovered a new library (at least to me) in the .NET community that aims to help developers constrain potential inputs using value objects.

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ASP.NET Core has a superpower that few other frameworks have, largely thanks to the Razor engine. Razor syntax is a mix of HTML and C#, and most Razor syntax implementations will skew heavily towards HTML over C#. However, C# syntax offers the most value in control flow mechanics using if, for, and switch statements. Razor’s power is that even HTML syntax is processed by C# and converted into compiled artifacts. This gives Razor a unique opportunity to do some amazing tricks.

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I recently saw that .NET 10 adds a numeric comparer, allowing you to sort string elements that may contain numeric values at the end of a string. Think movie sequels or number versions of an operating system. To my surprise, I could not believe it wasn’t already included in .NET, but then I sat down to try to write my own, and I now “get it”. The edge cases alone can drive you mad. Numeric ordering is subjective. Should the numbers come before Roman numerals? Should Roman numerals be parsed as numbers? What about decimals?

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The hallmark of every great project is equally great documentation, but it can be increasingly difficult for developers to keep both in sync. Luckily, I’ve been experimenting again with a combination of Starlight and MarkdownSnippets to make maintaining code samples and documentation much more convenient.

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Building dynamic JavaScript experiences has come a long in the 20 years since I first started software development, but updating the document object model (DOM) can still be a real pain in the butt. That’s why we’ve seen single-page application frameworks explode in use. While JavaScript provides a very capable API when interacting with the DOM, it can be verbose.

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If you read this blog, you likely know I predominantly work with .NET technologies and use web technologies such as HTML, CSS, and JavaScript. The web is an excellent space for new and exciting ways to solve age-old problems. I recently thought about the Blazor “Counter” example that ships with the Blazor Wasm template and how I’ve solved the same problem using Htmx. The issue with Htmx is that it still requires a backend to manage the state; in the case of a counter, this state is the current count. What if you wanted to build a self-contained client-side experience?

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I’m a big fan of static site renderers, and they are still one of the missing elements that would make ASP.NET Core more compelling for users across the vast ecosystem divide. In the meantime, developers must rely on tools like Astro, Jekyll, and 11ty to build static site experiences. Recently, I read about Astro 5.0 and its server island implementation. Server islands allow for mostly static pages to carve out portions of the page that will be rendered on-demand by, you guessed it, the server. This allows site authors to deliver fast, statically rendered pages that benefit the user while allowing for dynamic user-specific content.

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Let me start by saying that I love the combination of Htmx and ASP.NET Core, and it is a pairing that any .NET developer should consider, whether maintaining an existing application or building a new one. It’s very cool. I was recently talking about revisiting the hx-trigger and HX-Trigger header technique with ASP.NET Core on Mastodon with Illya Busigin, and they mentioned they use the same method to update the avatar image when a user updates their profile. So, I thought I’d try and see how to implement it myself.

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Folks working with EF Core are likely very fond of the library’s migration features, one of the most vital selling points for adopting an ORM. If you’re building a .NET solution, your database schema will evolve, and adding, removing, and updating are everyday actions you must perform.

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Community member Jonathan Channon recently approached me about an appropriate way to test your Htmx-powered applications using the Playwright testing framework. It can be annoying to get the timing right between sending an HTMX request, processing it on the server, and applying it to the page.

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JavaScript, for better or worse, has a much smaller standard library than what .NET developers are used to with the base class library (BCL). The JavaScript community has made many attempts to build a standard library, and I’m sure some of them are great. As I was scanning the options, I came across a fascinating method named intersperse, which “inserts a separator between the elements of its list argument”.

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The other day, I played around with the Fibonacci sequence and overflowed my int variables in surprisingly low iterations. Did you know you’ll overflow an integer in **48 ** iterations? Don’t believe me? Let’s take a look at the result of the code you’ll see later in this post.

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When building web experiences, there are safe operations and destructive ones. In the case of dangerous actions, it’s widespread to ask the user if they’d like to continue with the action before ultimately executing it.

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If you’ve ever worked with reflection in .NET, you’re likely familiar with Activator. In .NET 6, ActivatorUtilities was introduced to make it easier to create classes with dependencies. Constructor dependency injection is common in the .NET space, and you’re likely to run into several types that require constructor parameters before being created. The Activator class is a relic of a simpler time, whereas ActivatorUtilities meets developers where .NET is today.

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The evolution of the C# language has introduced us to many new features and probably made a lot of folks re-evaluate how they write their apps. In the latest versions of .NET, nothing has been marked such a stylistic shift as the introduction of top-level statements.

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