Create & Bind Structured Database To ListView C#

Question

I want to delete all items in ListView1 except youngest student in each group by comparing their date of births.

So, I tried to create a structured database and binding it to my ListView1 but failed with errors & exceptions.

Any help is greatly appreciated.

This is my code-

// 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();

//

My ListView1 contains-

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

jdweng · Accepted Answer · 2019-03-22 12:31:35Z

0

Try following :

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;}
    }

}

answered Mar 22, 2019 at 12:31

jdweng

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2 Comments

Dutaner Over a year ago

Thanks for your reply, Jdweng. When I imported the results variable into ListView1, it results in Nil value. listView1.Items.Clear(); int counterOfArraylist = results.Count; string[] str = new string[counterOfArraylist]; for (int i = 0; i < str.Length; i++) { str[i] = results[i].ToString(); } listView1.Items.Add(new ListViewItem(str));

jdweng Over a year ago

You have to use AddRange instead of Add when putting more than one item into a list. You can't do following : listView1.Items.Add(new ListViewItem(str)); See : stackoverflow.com/questions/9951704/…

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