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Tag: csharp

321 posts · Page 4 of 33

2026-08-23 ef-core linq csharp

How to write reusable LINQ predicates that EF Core can translate in Where, Select, and OrderBy

A bool helper method throws "could not be translated". An Expression<Func<T, bool>> does not. Here is how to compose, nest, and reuse expression trees in EF Core 11 without LINQKit, with the real SQL for every case.

2026-08-20 mcp agent-skills microsoft-agent-framework

How to Serve Agent Skills from an MCP Server in .NET with UseMcpSkills

Stop shipping SKILL.md folders inside every agent deployment. Serve them from an MCP server and pull them with UseMcpSkills on Microsoft.Agents.AI.Mcp 1.18. Includes the exact skill://index.json shape, a working C# server, the wire trace, and the SEP-2640 drift that will bite you.

2026-08-19 dotnet semantic-kernel ai-agents

Semantic Kernel 1.80.0 Stops OpenAPI Plugins From Following Redirects

Semantic Kernel .NET 1.80.0 ships a breaking change: the OpenAPI plugin's default HttpClient no longer follows redirects, closing an SSRF bypass. Here is what changes and why your own HttpClient reopens the hole.

2026-08-18 errors dotnet csharp

Fix: 'MapperConfiguration' does not contain a constructor that takes 1 arguments

AutoMapper 15 removed the single-argument MapperConfiguration constructor. Pass an ILoggerFactory as the second argument, and add a config action to every AddAutoMapper call.

2026-08-18 errors csharp csharp-14

Fix: The call is ambiguous between the following methods or properties after moving to C# 14 extension members

CS0121 after moving an extension method into a C# 14 extension block: the compiler still emits the old static form. Delete the duplicate or qualify the call.

2026-08-16 csharp dotnet dotnet-11

How to download a file from a Blazor component without JavaScript interop

Skip the downloadFileFromStream JS module entirely. Render an anchor with the download attribute pointing at a minimal API endpoint that returns TypedResults.File, or POST a plain HTML form with an AntiforgeryToken. Covers why the download attribute is what stops Blazor's enhanced navigation from swallowing the click, why data-enhance silently discards the file, and the cookie-vs-bearer auth trap.

2026-08-16 system-text-json csharp csharp-14

How to make System.Text.Json ignore a property that has the required modifier

[JsonIgnore] on a required member throws InvalidOperationException: marked required but does not specify a setter. Here is why the two features collide and the four ways to ignore the property anyway, measured on .NET 10.

2026-08-16 csharp dotnet dotnet-11

How to use IDbContextFactory<T> from a singleton service in Blazor

A singleton cannot inject a DbContext, but it can inject IDbContextFactory<T>, because AddDbContextFactory registers the factory as a singleton by default. Create and dispose one context per call, never cache the instance.

2026-08-15 dotnet-11 dotnet csharp

System.IO.Compression Finally Reads and Writes Encrypted ZIPs in .NET 11 Preview 7

.NET 11 Preview 7 adds password-protected ZIP entries to System.IO.Compression, with AES-256 support, options types for whole-directory operations, and one empty-file bug that is already fixed in main.

2026-08-15 comparison csharp dotnet

Scalar vs Swagger UI for OpenAPI documentation in ASP.NET Core 11

Scalar ships 1.02 MiB of gzipped JavaScript and a far better request builder. Swagger UI ships 514 KiB and renders OpenAPI 3.2, which is what .NET 11 now emits by default. Measured payloads, the 3.2 gap, endpoint routing on both sides, and the auth details that decide it.