>>710
app.config(古めの方法)
https://learn.microsoft.com/ja-jp/visualstudio/ide/managing-application-settings-dotnet?view=vs-2022

汎用ホストにAddJson(新しめの方法)
https://learn.microsoft.com/ja-jp/aspnet/core/fundamentals/host/generic-host?view=aspnetcore-6.0

かなり古いけど長年採用されてきた方法
https://dobon.net/vb/dotnet/programing/storeappsettings.html