C# switch 表达式 - 使用 switch 关键字的模式匹配表达式

https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/switch-expression

        [DisplayName("空气质量指数颜色")]
        public string TvocColor => AQI switch
        {
            1 => "green",
            2 => "yellow",
            3 => "orange",
            4 => "red",
            5 => "purple",
            6 => "brown",
            _ => "green",
        };

        [DisplayName("空气质量指数评级")]
        public string TvocLevel => AQI switch
        {
            <= 3 => "优",
            <= 7 => "良",
            >= 8 => "差",
            _ => "优",
        };