List分组操作

class Program    {        static void Main(string[] args)        {            List<Student> list = new List<Student>()           {           new Student{Name="aaa",ClassName="a",Age=20,StuNo="a001"},           new Student{Name="bbb",ClassName="a",Age=18,StuNo="a003"},           new Student{Name="ccc",ClassName="b",Age=20,StuNo="b001"},           new Student{Name="ddd",ClassName="b",Age=20,StuNo="b045"},           new Student{Name="eee",ClassName="c",Age=20,StuNo="c001"},           new Student{Name="fff",ClassName="c",Age=20,StuNo="c008"},           new Student{Name="ggg",ClassName="c",Age=20,StuNo="c050"},           new Student{Name="hhh",ClassName="c",Age=20,StuNo="c007"}           };            //添加testStr 元素            IEnumerable<IGrouping<string, Student>> query = list.GroupBy(x =>x.ClassName);            foreach (IGrouping<string, Student> info in query)            {                Console.WriteLine("班级:" + info.Key);                List<Student> sl = info.ToList<Student>();//分组后的集合                foreach (Student item in sl)                {                    Console.WriteLine("姓名:" + item.Name + "\t班级:" + item.ClassName + "\t年龄:" + item.Age + "\t学号:" + item.StuNo);                }            }                     Console.Read();        }    }    class Student    {        public string Name { get; set; }        public string ClassName { get; set; }        public int Age { get; set; }        public string StuNo { get; set; }    }