Iterate Through a Dictionary in C#: .NET 10, Keys/Values samples, honest benchmarks

[vladimir-pecanac-main]

Sample update for https://code-maze.com/csharp-iterate-through-dictionary/ (collections-dictionary/IterateThroughDictionary only).

• All three projects net6.0 to net10.0.
• Packages, re-queried on NuGet 2026-10-04 (newest stable): BenchmarkDotNet 0.15.8, Microsoft.NET.Test.Sdk 18.10.1, MSTest.TestAdapter 4.4.1, MSTest.TestFramework 4.4.1, coverlet.collector 10.1.0. dotnet list package --vulnerable --include-transitive is clean.
• New sample methods SubDictionaryUsingKeys, SubDictionaryUsingValues and SubDictionaryRemoveWhileIterating, each with a test.
• WhenDictionaryUsesParallelEnumerable_ThenOutputsReqdResults could not fail (every assert sat inside an if comparing the same values); it now uses CollectionAssert.AreEquivalent over the four expected lines.
• Benchmarks: the dead stores are fed to BenchmarkDotNet Consumer. The string concatenation benchmark the article describes is now in the repo; its parallel case accumulates per thread (ThreadLocal) and joins at the end instead of writing to one shared local from every thread, which lost most of the appends (10,000 entries: 11,584 of 98,890 characters). All three methods now return the full 98,890-character result.
• File-scoped namespaces, ImplicitUsings on the test project, stray space inside an interpolation hole removed.

Build 0 warnings, 7 of 7 tests pass, SDK 10.0.302 / .NET 10.0.10.