一、数据准备
public class Student { public int ID { get; set; } public string Name { get; set; } public string Gender { get; set; } public string Branch { get; set; } public int Age { get; set; } public static List<Student> GetAllStudents() { return new List<Student>() { new Student { ID = 1001, Name = "玲玲", Gender = "Female", Branch = "CSE", Age = 20 }, new Student { ID = 1002, Name = "张三", Gender = "Male", Branch = "ETC", Age = 21 }, new Student { ID = 1003, Name = "李四", Gender = "Male", Branch = "CSE", Age = 21 }, new Student { ID = 1004, Name = "王五", Gender = "Male", Branch = "CSE", Age = 20 }, new Student { ID = 1005, Name = "珊珊", Gender = "Female", Branch = "ETC", Age = 20 }, new Student { ID = 1006, Name = "涵涵", Gender = "Female", Branch = "CSE", Age = 21 }, new Student { ID = 1007, Name = "钱六", Gender = "Male", Branch = "CSE", Age = 22 }, new Student { ID = 1008, Name = "婷婷", Gender = "Female", Branch = "CSE", Age = 20 }, new Student { ID = 1009, Name = "兰兰", Gender = "Female", Branch = "ETC", Age = 22 }, new Student { ID = 1010, Name = "黄九", Gender = "Male", Branch = "ETC", Age = 21 } }; } }
二、GroupByMultipleKeys
//Using Query Syntax Console.WriteLine("方式一:"); var GroupByMultipleKeysQS = from std in Student.GetAllStudents() group std by new { std.Branch, std.Gender } into stdGroup orderby stdGroup.Key.Branch descending, stdGroup.Key.Gender ascending select new { Branch = stdGroup.Key.Branch, Gender = stdGroup.Key.Gender, Students = stdGroup.OrderBy(x => x.Name) }; foreach (var group in GroupByMultipleKeysQS) { Console.WriteLine($"Branch:{group.Branch} Gender:{group.Gender} No of Students={group.Students.Count()}"); foreach (var student in group.Students) { Console.WriteLine($"ID:{student.ID},Name:{student.Name},Age:{student.Age}"); } } //Using Query Syntax Console.WriteLine("方式二:"); var GroupByMultipleKeysMS = Student.GetAllStudents() .GroupBy(x => new { x.Branch, x.Gender }) .OrderByDescending(g => g.Key.Branch).ThenBy(g => g.Key.Gender) .Select(g => new { Branch = g.Key.Branch, Gender = g.Key.Gender, Students = g.OrderBy(x => x.Name) }); foreach (var group in GroupByMultipleKeysMS) { Console.WriteLine($"Branch:{group.Branch} Gender:{group.Gender} No of Students={group.Students.Count()}"); foreach (var student in group.Students) { Console.WriteLine($"ID:{student.ID},Name:{student.Name},Age:{student.Age}"); } }
三、测试结果
![](/i/l/?n=22&i=blog/1222783/202208/1222783-20220826171111899-1664549087.png)
四、参考网址
https://dotnettutorials.net/lesson/groupby-multiple-keys-in-linq/
个人代码见....CSharpBasic\LINQTutorial.. 标签:GroupByMultipleKeys,Name,Gender,Age,LINQ,Branch,new,ID From: https://www.cnblogs.com/keeplearningandsharing/p/16628265.html