system-text-json-net11

System.Text.Json — .NET 11

Three APIs were added to System.Text.Json in .NET 11. This skill tells you exactly when to reach for each one, what to write, what not to write, and how to prove the result runs. Do not describe these APIs to the user — apply them, then run the code and show the output.

API	Replaces the pre-.NET-11 workaround of...
JsonNamingPolicy.PascalCase (static property)	writing a custom JsonNamingPolicy subclass or hand-annotating every member with [JsonPropertyName]
JsonSerializerOptions.GetTypeInfo<T>()	calling non-generic GetTypeInfo(typeof(T)) and casting to JsonTypeInfo<T>
JsonSerializerOptions.TryGetTypeInfo<T>(out JsonTypeInfo<T>? info)	wrapping GetTypeInfo in try/catch to probe availability

Step 0 — Make the requested net11.0 validation possible

These APIs only exist in the .NET 11 base class library. Before writing code:

1. Run dotnet --list-sdks and confirm an SDK that can target net11.0 is present — an 11.x SDK, or a later SDK with the net11.0 targeting pack.
2. If the user explicitly asks you to run the sample and no suitable SDK is installed, use the official dotnet-install script to install the current .NET 11 SDK into a temporary or project-local directory. Prefer the GA channel build. Use a preview only when GA is not yet available or the user explicitly requested a preview. Do not require administrator access, change the machine-wide PATH, or replace an installed SDK.
3. Run the sample with that local dotnet executable. If download or execution is blocked, still provide the complete net11.0 program and report that it was not run. Never substitute net10.0, a custom naming policy, or a different API and present that as validation of the .NET 11 feature.

Use the channel, not a guessed version. Try the GA channel first:

$installScript = Join-Path $env:TEMP "dotnet-install-$([guid]::NewGuid()).ps1"
try {
    Invoke-WebRequest -Uri 'https://dot.net/v1/dotnet-install.ps1' -OutFile $installScript
    & $installScript -Channel 11.0 -InstallDir .\.dotnet
    & .\.dotnet\dotnet.exe run --project <PATH_TO_NET11_PROJECT>
}
finally {
    Remove-Item -LiteralPath $installScript -Force -ErrorAction SilentlyContinue
}