Browse .NET News (77)

James Rempt shares takeaways from VSLive! San Diego on how experienced Visual Studio developers are adopting GitHub Copilot and other AI tools, while spending more time validating generated code and leaning on hands-on learning. The post also highlights how Visual Studio Subscription benefits support ongoing skill-building.

.NET Team announces .NET 11 Release Candidate 2, highlighting updates across the runtime, SDK, MSBuild, NuGet, F#, ASP.NET Core, .NET MAUI, and Windows Forms, plus links to detailed release notes and guidance for getting started with the RC2 tooling.

Rahul Bhandari and Tara Overfield recap the October 2026 servicing releases for .NET and .NET Framework, highlighting security and non-security fixes and pointing to the official CVE lists, release notes, installers, container images, Linux package guidance, and known-issues pages for supported versions.

Tamir Dresher explains where Durable Task (and Durable Task Scheduler) actually helps in production: coordinating long-running workflows that need durable waits, replay, and recovery. Using five concrete scenarios—including Azure tenant provisioning and an AI-assisted incident workflow—he shows what durability solves and what your app still must own.

Allison announces CodeQL 2.27.2, detailing new and improved analysis across C/C++, Go, Rust, and JavaScript/TypeScript, plus notable query updates for C# and GitHub Actions. The post also calls out a macOS 27/Xcode 27 limitation for traced analysis and a breaking change in the Go control-flow graph library.

The Visual Studio Code Team shares the release notes landing page for VS Code 1.142 (Insiders), with links to the commit log and closed issues so developers can track what’s changing as features land in the Insiders build.

Drew Noakes explains how C# Dev Kit 11.0 (aligned with .NET 11) was rearchitected to dramatically reduce solution load times and memory usage in VS Code, while also speeding up incremental builds and improving MSBuild file editing with richer language features.

Lily Ma introduces Azure Functions managed connectors (public preview) and shows how connector triggers and typed clients let functions react to events and call actions across services like SharePoint and Teams without hand-rolling webhook registration or OAuth token handling.

Amaury Levé explains how to run reliable UI-thread tests for UWP and WinUI 3 apps using MSTest 4.5 and Microsoft.Testing.Platform, including how packaged/unpackaged and AppContainer hosts change the test launch path and what to validate on CI agents.

Justin Bettencourt rounds up the September 2026 Azure SDK releases across .NET, Java, JavaScript/TypeScript, Python, Go, Rust, and C++, calling out notable updates like Azure AI Search preview API support, a stable Rust SAS crate, and new Entra ID authentication libraries for PostgreSQL.

Mark Downie outlines the September Visual Studio update, including Bring Your Own Model (BYOM) for Copilot-powered agent mode, one-click fixes for NuGet Audit vulnerability warnings from the Error List, a Git agent for pull request exploration, improved C# debugging hints for compound if conditions, and Podman container attach support.

Daniel Roth introduces experimental Blazor AI components in .NET 11 RC1 for building “Agentic UI”: streamed agent output rendered as structured content blocks, tool calls, approvals, and shared state. The post walks through the AgenticUI sample architecture using Microsoft.Extensions.AI, AG-UI, Microsoft Agent Framework, ASP.NET Core, Foundry, and Aspire.

Daniel Roth announces the new AG-UI .NET SDK and shows how to expose and consume interoperable agent endpoints from .NET using Microsoft.Extensions.AI. The post explains the AG-UI event model, includes an ASP.NET Core quickstart for streaming Server-Sent Events, and outlines how Microsoft Agent Framework now builds on the shared AGUI.* packages.

Allison summarizes what’s new in CodeQL 2.27.1, including new and improved queries across multiple languages, Kotlin 2.4.20 support, and accuracy fixes that affect GitHub code scanning results for C#, ASP.NET Core, and GitHub Actions workflows.

Dan Taylor walks through recent Microsoft Agent Framework updates that make agents more usable in real apps: interactive UIs via AG-UI, longer-term memory via Foundry Agent Service (and Cosmos DB alternatives), CodeAct for multi-step execution, and resilient hosting for recoverable long-running workflows in both Python and .NET.

The NuGet Team explains how to prepare for Microsoft’s NuGet author-signing certificate rollover on September 23, 2026, including who is impacted and the exact commands and configuration changes needed to keep trusted-signer policies and package verification working.

Aaron Powell walks through diagnosing a production hang in a C# app by capturing a memory dump and analyzing it in Visual Studio, using Parallel Stacks to spot thread-pool saturation and then using GitHub Copilot to help interpret what the dump is showing.

Aaron Powell shows how to generate memory dumps from a C# app when it becomes unresponsive, so you can debug production hangs with more than just logs. The article includes a thread-pool saturation watcher, Windows dump creation via dbghelp.dll, and Linux dump creation via the .NET runtime’s createdump utility.

Roger Barreto and Tao Chen explain how Foundry hosted agent isolation works in Microsoft Agent Framework, breaking it into user isolation (who the request represents) and session isolation (which sandbox and files persist). They show how to pass delegated identities and how to create, reuse, and pool Foundry hosted sessions in .NET and Python.

Bruno Capuano introduces MafClaw, a four-part live series that builds a production-ready AI agent in C# using the Microsoft Agent Framework harness—starting from a minimal IChatClient wrapper and progressively adding tools, planning, safe file access, approvals, memory, skills, code execution, observability, governance, evaluations, and deployment to Microsoft Foundry.

Tommaso Stocchi compares two multi-agent architectures in Microsoft Agent Framework: delegating work to specialist agents over A2A versus moving specialist instructions into distributed skills served over MCP, with concrete migration steps, code snippets, and measured differences in model calls, latency, and token usage.

Aaron Powell shows how to baseline and then raise unit test coverage in the Interview Coach app using Visual Studio’s code coverage tooling and GitHub Copilot’s Test Agent, moving from targeted tests for a single class to solution-wide analysis and test generation.

Justin Yoo walks through a sample “Interview Coach” app that uses the GitHub Copilot SDK as an agent runtime (outside the editor) to run an interview workflow: ingest a resume, ask behavioral/technical questions, store session context, and generate end-of-interview feedback using MCP tools and Agent Framework handoffs.

Stephen Toub walks through a large set of runtime and library performance changes in .NET 11, with runnable micro-benchmarks and disassembly examples. It covers JIT optimizations (devirtualization, escape analysis, bounds-check removal), a new runtime-driven async implementation, SIMD/codegen improvements, and faster paths across core libraries like networking, JSON, regex, and collections.

Luis Quintanilla invites teams to submit real-world stories about building, modernizing, and improving applications with .NET, with the goal of featuring more community and customer examples at .NET Conf 2026 and across official .NET channels.

Dmitrii Korolev explains how C# 15 union types and closed class hierarchies behave in ASP.NET Core when serialized with System.Text.Json, including what works in Minimal APIs, MVC, SignalR, Blazor, and OpenAPI, plus the trade-offs around discriminator-free JSON and ambiguous payloads.

Allison announces CodeQL 2.27.0, highlighting native Linux ARM64 support, improvements to GitHub code scanning default setup, and multiple query and framework-modeling updates that improve vulnerability detection across C#, Java/Kotlin, C/C++, and Rust projects.

.NET Team announces .NET 11 Release Candidate 1, highlighting runtime, SDK, MSBuild, NuGet, and language updates, plus ASP.NET Core, .NET MAUI, and Windows Forms improvements. The post links to detailed release notes and includes download and tooling guidance for trying RC1 in production.

Javier Lozano, Chris Sfanos, and Jon Galloway announce that the call for presenters is open for .NET Conf 2026 Community Days, with session proposals accepted from September 8 through October 6, 2026, and a separate volunteer opportunity for helping run the event.

Rahul Bhandari and Tara Overfield recap the September 2026 servicing releases for .NET and .NET Framework, highlighting security and non-security fixes, the list of addressed CVEs, and where to find release notes, installers, container images, Linux packages, and known issues for supported versions.

Justin Yoo walks through a practical profiling workflow for distributed .NET apps, showing how to identify which process owns a slow user interaction, use Visual Studio CPU profiling to rule out CPU-bound work, and then measure hidden async waiting that doesn’t show up in CPU samples.

Justin Bettencourt’s August 2026 Azure SDK roundup highlights new and updated client libraries across .NET, Java, JavaScript/TypeScript, Python, Go, and more, including Document Translation 2.0.0, Azure Storage Blobs 12.30.0-beta.1, and the first stable release of Azure AI Discovery.

Amaury Levé explains how MSTest 4.4 uses source generation to make test projects publishable and runnable as Native AOT executables, so your tests exercise the same trimming and reflection constraints as the app you deploy.

Allison summarizes what’s new in CodeQL 2.26.4 for GitHub code scanning, including language support updates and query accuracy improvements that affect security detections across C#, Java/Kotlin, and GitHub Actions workflows.

The Visual Studio Code Team shares Insiders updates for VS Code 1.137, focusing on Copilot-related workflow improvements such as clearer model token limits, better context handling when pasting GitHub issue/PR links, and updated new-session composer controls.

Mads Kristensen shows how to give each Visual Studio solution its own color theme so multiple IDE instances are easier to tell apart. He also explains the new scoped settings model in Visual Studio 2026, where solution-level settings are stored in a JSON file you can optionally commit to source control for consistent team setup.

Aaron Powell walks through reviewing GitHub pull requests directly inside Visual Studio, from opening the PR list and navigating diffs to leaving inline comments, approving, and merging. He also shows how to bring GitHub Copilot into the review by adding a PR as chat context using the UI or the #pullrequest: command.

Allison summarizes the August 2026 update for GitHub Copilot in Visual Studio, including organization-level custom agents, usage visibility, model selection and “thinking effort” controls, and a Git agent that can review uncommitted changes or commits before opening a pull request.

Allison summarizes the August 24 weekly GitHub Copilot updates, covering shared agent sessions in Slack and Microsoft Teams, the Copilot app’s new Customize experience (including MCP servers and plugins), Copilot CLI session and permission defaults, and IDE improvements across VS Code, JetBrains, and Visual Studio.

Sam Basu explains how Uno Platform built two MCP servers in C#—one for documentation grounding and one for driving a live app—so AI agents can look up accurate APIs, run and inspect a cross-platform .NET UI, and validate changes instead of just generating code.