Question

我想通过比较出生日期来删除ListView1中除所有组中最小的学生以外的所有项目。

因此，我尝试创建一个结构化的数据库并将其绑定到我的ListView1，但是由于错误和异常而失败。

非常感谢您的帮助。

这是我的代码-

// assume 'Students is a List<Student>
IEnumerable<Student> earlydatestudents = Students.GroupBy(std => std.Group)
    .Select(grp =>
    {
        DateTime dt = grp.Min(s => s.DOB);
        return grp.Where(st => st.DOB == dt);
    })
    .SelectMany(slist => slist);

var toDeleteList = Students.Except(earlydatestudents).ToList();

//

我的ListView1包含-

Student , DOB , Location

Group1
AAA     10-05-2000  Mumbai
BBB     05-02-2000  Pune
CCC     01-01-2000  Delhi

Group2
DDD     20-03-1999  Lucknow
EEE     15-06-1999  Chennai
FFF     18-09-1999  Ahmedabad

Answer 1

尝试以下操作：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;

namespace ConsoleApplication106
{
    class Program
    {
        static void Main(string[] args)
        {
            List<Student> students = new List<Student>() {
                new Student() { name = "AAA", dob = DateTime.ParseExact("10-05-2000", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Mumbai"},
                new Student() { name = "BBB", dob = DateTime.ParseExact("05-02-2000", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Pune"},
                new Student() { name = "CCC", dob = DateTime.ParseExact("01-01-2000", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Delhi"},
                new Student() { name = "DDD", dob = DateTime.ParseExact("20-03-1999", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Lucknow"},
                new Student() { name = "EEE", dob = DateTime.ParseExact("15-06-1999", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Chennai"},
                new Student() { name = "FFF", dob = DateTime.ParseExact("18-09-1999", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Ahmedabad"}
            };


            var results = students.OrderByDescending(x => x.dob)  //sort from youngest to oldest
                .GroupBy(x => x.dob.Year) //group by year
                .Select(x => x.First())  //get first student born each year which is youngest
                .ToList();
        }

    }
    public class Student
    {
        public DateTime dob { get; set; }
        public string name { get; set; }
        public string location { get; set;}
    }

}

创建结构化数据库并将其绑定到ListView C＃

1 个答案: