C# 14 features

The C# Dev Kit team swapped its C++ Node.js addon for a .NET 10 Native AOT library, using N-API, UnmanagedCallersOnly, and LibraryImport to produce a single .node file without Python or node-gyp.

Seven ways to return more than one value from a C# 14 method: named tuples, out parameters, records, structs, deconstruction, and the extension-member trick for types you don't own. Real benchmarks and a decision matrix at the end.

.NET 11 Preview 3 teaches RyuJIT to eliminate redundant bounds checks on consecutive index-from-end access and on i + constant < length patterns, cutting branch pressure in tight loops.

.NET 11 Preview 3 adds RegexOptions.AnyNewLine so ^, $, \Z, and . recognize every Unicode newline sequence, including \r\n, NEL, LS, and PS, with \r\n treated as one atomic break.

EF Core 11 Preview 3 removes redundant to-one joins from split queries and drops unneeded ORDER BY keys. One reported scenario got 29% faster, another 22%. Here is what the SQL now looks like.

.NET 11 Preview 3 finishes the naming-policy story in System.Text.Json: JsonNamingPolicy.PascalCase, a member-level [JsonNamingPolicy] attribute, and a type-level [JsonIgnore] default for cleaner DTOs.

EF Core 11 Preview 3 introduces ChangeTracker.GetEntriesForState, a state-filtered enumerator that avoids an extra DetectChanges pass in hot paths like SaveChanges interceptors and audit hooks.

Loic Baumann's Typhon project targets 1-2 microsecond ACID commits using ref structs, hardware intrinsics, and pinned memory, proving C# can compete at the systems programming level.

C# 14 lets you overload +=, -=, *=, and friends as void instance methods that mutate the receiver in place, cutting allocations for large value holders like BigInteger-style buffers and tensors.

C# strings sent through Dapper default to nvarchar(4000), forcing SQL Server into implicit conversions and full index scans. Here's how to fix it with DbType.AnsiString.

.NET 11 Preview 1 ships ZstandardStream, ZstandardEncoder, and ZstandardDecoder in System.IO.Compression, giving you fast, inbox zstd support with no third-party packages.

The dotnet ef database update command now accepts --add to scaffold and apply a migration in a single step. Here is how it works, why it matters for containers and .NET Aspire, and what to watch for.

EF Core 11 Preview 2 supports SQL Server 2025 VECTOR_SEARCH() and DiskANN vector indexes directly from LINQ. Here is how to set up the index, run approximate queries, and what changes from the EF Core 10 VectorDistance approach.

JetBrains shipped ReSharper as a VS Code extension with full C# analysis, refactoring, and unit testing. It works in Cursor and Google Antigravity too, and costs nothing for OSS and learning.

C# 15 introduces the union keyword for type unions with exhaustive pattern matching and implicit conversions. Available now in .NET 11 Preview 2.

Microsoft Agent Framework hits 1.0 with stable APIs, multi-provider connectors, multi-agent orchestration, and A2A/MCP interop. Here is what it looks like in practice on .NET 10.

Runtime Async in .NET 11 moves async/await handling from compiler-generated state machines into the runtime itself, producing readable stack traces, correct breakpoints, and fewer heap allocations.

C# 14 introduces extension members, allowing you to add extension properties, operators, and static members to existing types using the new extension keyword.

A community discussion proposed using C# 14 interceptors to rewrite JsonSerializer calls so they automatically use a generated JsonSerializerContext, keeping AOT-friendly source generation with cleaner call sites.

C# 14 extends null-conditional operators to work on the left-hand side of assignments, eliminating verbose null checks when setting properties or indexers.

A new Polars.NET project is trending after a Feb 6, 2026 community post. The headline is simple: a .NET-friendly DataFrame API backed by Rust Polars, with a stable C ABI and LibraryImport-based interop to keep overhead low.

Miyanyedi Quick Note is a WinUI 3 + SQLite note-taking app that is offline-first and privacy-friendly. Here is why local-only is a feature, plus a minimal SQLite snippet for .NET 8 desktop apps.

CV Shortlist is an open-source .NET 10 SaaS that pairs Azure Document Intelligence with an OpenAI model. The stack, config discipline, and AI integration boundary are worth studying.

ModularPipelines V3 lets you write CI pipelines in C# instead of YAML. Run them locally with dotnet run, get compile-time safety, and debug with breakpoints.

How to wire Model Context Protocol (MCP) servers in C# on .NET 10 using microsoft/mcp. Covers tool contracts, input validation, auth, observability, and production-readiness patterns.

A look at the C# discriminated unions proposal: the union keyword, exhaustive pattern matching, and how it could replace OneOf libraries and class hierarchies.

C# 13 finally eliminates the hidden array allocation behind params. You can now use params with Span, ReadOnlySpan, List, and other collection types for zero-allocation variadic methods.

C# 14 allows using ref, out, in, scoped, and ref readonly modifiers on implicitly typed lambda parameters, eliminating the need to explicitly declare parameter types.

C# 14 lets you declare instance constructors and events as partial members, splitting definitions across files for cleaner code generation and separation of concerns.

C# 14 enhances the nameof expression to support unbound generic types like List<> and Dictionary<,>, eliminating the need for placeholder type arguments.

C# 14 adds built-in implicit conversions between Span, ReadOnlySpan, arrays, and strings, enabling cleaner APIs, better type inference, and fewer manual AsSpan() calls.

C# 14 introduces the field contextual keyword for property accessors, letting you add custom logic to auto-properties without declaring a separate backing field.

.NET 9 significantly improves ToArray performance using InlineArray, making it faster and more memory-efficient than ToList. See benchmarks comparing .NET 8 vs .NET 9.

C# 13 extends the params modifier beyond arrays to support Span, ReadOnlySpan, IEnumerable, and other collection types, reducing boilerplate and improving flexibility.

How to fix 'Feature is not available in C# 12.0' and switch your project to C# 13 by changing the target framework or setting LangVersion in your .csproj file.

A summary of all new features in C# 14.0, including the field keyword, extension members, null-conditional assignment, implicit span conversions, and more.

The evolution of C# has transformed it into a modern, high-performance language. This guide tracks every major milestone. The Early Years (C# 1.0 – 1.2) C# launched in 2002 as a primary language for the .NET Framework. It felt like Java but with a focus on Windows development. Version 1.2 arrived shortly after with small…

In C#, you can randomly select items from a list using Random.GetItems, a method introduced in .NET 8. Learn how it works with practical examples.

Learn how to register view handlers and services from within a .NET MAUI library using the builder pattern and MauiAppBuilder extension methods.

Fix the C# error where sizeof cannot be used with Point outside an unsafe context. Two solutions: enabling unsafe code or using Marshal.SizeOf instead.

Use UnsafeAccessorAttribute in .NET 8 to access auto-generated backing fields of private auto-properties in C# without reflection.

.NET 8 includes new CreateFromDirectory and ExtractToDirectory overloads that let you create and extract ZIP files directly to and from a Stream, without writing to disk.

Benchmarking GetGenericTypeDefinition in .NET 8 vs .NET 7 shows nearly 10x faster performance. See benchmark code and results using BenchmarkDotNet.

Learn how to capture a screenshot of your entire desktop from a .NET console application using System.Windows.Forms. Windows-only solution covering all displays.

Learn how to update a readonly field in C# using UnsafeAccessor, an alternative to reflection without the performance penalty. Available in .NET 8.

Benchmarking UnsafeAccessor vs Reflection in .NET 8. See how UnsafeAccessor achieves zero-overhead performance compared to traditional reflection.

Starting with C# 12, a new ExperimentalAttribute lets you mark types, methods, properties, or assemblies as experimental. Learn how to use it with diagnosticId, pragma tags, and UrlFormat.

The ref readonly modifier in C# provides a more transparent way of passing read-only references. Learn how it improves on the in modifier with better constraints and caller visibility.

The easiest way to shuffle an array in C# is using Random.Shuffle, introduced in .NET 8. It works in-place on both arrays and spans.

Learn what causes a NullReferenceException in C#, how to debug it, and how to prevent it using null checks, the null-conditional operator, and nullable reference types.

Learn how to add or remove TypeInfoResolver instances on existing JsonSerializerOptions using the new TypeInfoResolverChain property in .NET 8.

Learn about C# 12 interceptors, an experimental .NET 8 compiler feature that lets you replace method calls at compile time using the InterceptsLocation attribute.

Fix the ASP.NET Core Identity error where AppDbContext can't be converted to IUserStore by adding AddEntityFrameworkStores to your identity configuration.

.NET 8 adds support for serializing properties from interface hierarchies, including all properties from all interfaces depending on the declared variable type.

Learn how to deserialize JSON into non-public properties in .NET 8 using the JsonInclude attribute and parameterized constructors.

Learn how to use the new JsonStringEnumConverter<TEnum> in .NET 8 for native AOT-compatible enum serialization with System.Text.Json.

How to fix error CS0246 for InterceptsLocationAttribute in C# interceptors by defining the attribute yourself.

Learn how to mark JsonSerializerOptions instances as read-only in .NET 8 using MakeReadOnly, and how to check the IsReadOnly property.

System.Text.Json in .NET 8 adds built-in serialization support for the Half, Int128, and UInt128 numeric types.

Starting with .NET 8, both Memory<byte> and ReadOnlyMemory<byte> are serialized as Base64 strings, while other types like Memory<int> remain JSON arrays.

Learn how to include private, protected, and internal properties in JSON serialization in .NET 8 using the JsonInclude attribute.

Inline arrays enable you to create an array of fixed size in a struct type. Such a struct, with an inline buffer, should provide performance comparable to an unsafe fixed size buffer. Inline arrays are mostly to be used by the runtime team and some library authors to improve performance in certain scenarios. You likely…

C# 12 introduces a new simplified syntax for creating arrays. It looks like this: It’s important to note that the array type needs to be specified explicitly, so you cannot use var for declaring the variable. Similarly, if you wanted to create a Span<int>, you can do: Multi-dimensional arrays The advantages of this terse syntax…

You can use the WaitForExit method to wait for the process to complete. Your code will wait synchronously for the process to finish, then it will resume execution. Let’s look at an example: The code above will start a new cmd.exe process, and execute the timeout 5 command. The process.WaitForExit() call will force your program…

The using alias directive has been relaxed in C# 12 to allow aliasing any sort of type, not just named types. This means that you can now alias tuples, pointers, array types, generic types, etc. So instead of using the full structural form of a tuple, you can now alias it with a short descriptive…

The With…End With statement in VB allows you to execute a series of statements that repeatedly refer to a single object. Thus the statements can use a simplified syntax for accessing members of the object. For example: Is there a C# syntax equivalent? No. There is not. The closest thing to it would be the…

Starting from C# 12, it is possible to define a primary constructor within classes and structs. The parameters are placed in parentheses right after the type name. The parameters of a primary constructor have a broad scope. They can be utilized to initialize properties or fields, serve as variables in methods or local functions, and…

A beginner's guide to getting started with C# programming, from setting up Visual Studio to writing your first program and finding learning resources.

Fix C# 12 language version errors by updating your target framework to .NET 8 or setting LangVersion in your .csproj file.

An overview of new features in C# 12, including primary constructors, default lambda parameters, collection expressions, inline arrays, and more.

C# 12 lets you specify default parameter values and params arrays in lambda expressions, just like in methods and local functions.

Learn how to define and use generic attributes in C# 11, including restrictions on type arguments and common error messages.

Learn how the C# 11 file access modifier restricts a type's scope to the file in which it is declared, helping avoid name collisions with source generators.

Learn how to use interpolated raw string literals in C# 11, including escaping braces, multiple $ characters, and conditional operators.

Learn how to use C# 11 raw string literals to include whitespace, new lines, and embedded quotes without escape sequences.

Fix the 'Feature is not available in C# 10.0' error by switching to C# 11 via target framework or LangVersion in your .csproj file.

Use ArgumentNullException.ThrowIfNull in .NET 6+ for concise null checks, or use throw expressions in C# 7+ for older frameworks.

Learn how to retrieve an embedded resource stream in .NET Core by understanding how resource names are composed and using GetManifestResourceStream.

Learn how to use appsettings.json configuration files with Xamarin.Forms by embedding the file as a resource and building an IConfiguration object.

Use ngrok to publicly expose your local SignalR service so mobile clients can connect without network configuration or SSL workarounds.

Learn how C# 8 using declarations (using var) simplify resource management by eliminating extra curly braces and indentation for IDisposable objects.

Learn how the C# 8.0 null-coalescing assignment operator (??=) works, with practical examples including caching and conditional assignment.

Create a smooth animated background effect in Xamarin Forms using ScaleTo animations on layered BoxViews.

Benchmarking how long it takes a PC to count to one trillion and beyond, with updated results from 2023.

Add speech recognition to your Windows Phone 8 app using the SpeechTextBox control from the Windows Phone toolkit.

Use a ScheduledTaskAgent to periodically update your Windows Phone live tiles from an RSS feed.

Create wide live tiles for both Windows Phone 7 and 8 using the MangoPollo library with a single piece of code.

A C# extension method that converts hex color codes (both RGB and ARGB formats) to Color objects.

Learn how code snippets in Visual Studio can improve your productivity by letting you insert reusable pieces of code with a short alias.