C# 编程/关键字/when

在 catch 语句或 switch 语句的 case 标签中，when 上下文关键字用于提供过滤功能。该关键字紧接在条件之前，例如 when (lifeValue < 1)。

C# 关键字
abstract as base bool break byte case catch char checked class const continue decimal default delegate do double else enum event explicit extern false finally fixed float for foreach goto if implicit in int interface internal is lock long namespace new null object operator out override params private protected public readonly ref return sbyte sealed short sizeof stackalloc static string struct switch this throw true try typeof uint ulong unchecked unsafe ushort using var virtual void volatile while
特殊的 C# 标识符（上下文关键字）
add alias async await dynamic get global nameof partial remove set value when where yield
上下文关键字（用于查询）
ascending by descending equals from group in into join let on orderby select where