按用户指定的键的动态列表对IEnumerable进行分组

I have a class like

我有一门课

public class Empolyee
{
    public string Designation {get ;set;}
    public string Discipline {get ;set;}
    public int Scale {get ;set;}
    public DateTime DOB {get ;set;}
    public int Sales {get ;set;}
}
public class Empo