Compare two lists on razor and sort them by newest (both have created datetime)

Question

I want to sort two models by Datetime, both of them going to one timeline so i need the newest from them to be on the start of the list timeline, I found solutions like Union models, but I want them to remain two separate lists..Is it possible?

foreach (var list1 in model.list1.OrderByDescending(a => a.created_datetime))
{
    09/18/19
}

foreach (var list2 in model.list2.OrderByDescending(a => a.created_datetime))
{
    09/19/19
}

Now I want the timeline result to be listed in the second list because it is an earlier result

It's not clear to me what you're asking. Are you just looking for the `.OrderBy()` extension method to sort your collections? — David, Sep 19 '19 at 17:08
Thanks for your response, I want to sort them out by Datetime, let's say if the first list has a date that is yesterday and the second one has a date whose date today then the second record will be displayed first — Daniel, Sep 19 '19 at 17:12
@DanielC how can you keep the lists separate _and_ blend them together? I am very unclear what you are asking — maccettura, Sep 19 '19 at 17:12
@DanielC: Perhaps you could include a more complete example, with data, and the intended output? It's not clear how you want to keep the lists separate but sort them together. — David, Sep 19 '19 at 17:13
Thanks for your response, this is what I am trying to figure out if there is a way to condition something like this or just unite them? — Daniel, Sep 19 '19 at 17:14

LeBoucher · Answer 1 · 2019-09-19T17:26:27.237

This is what you mean? (Using Linq)

var merged = list1.Union(list2).OrderByDescending(d => d.Date);

Note that this is only possible, when the two lists are the same type. Other note, that this returns an IEnumerable, not a new List, so every time you enumerate it, the merge will be calculated. You have to call ToList() at the end if you want to create a new List to prevent this, but this can be very suboptimal in performance if you have large lists.

Example program:

using System;
using System.Collections.Generic;
using System.Linq;

namespace Lists
{
    class Program
    {
        static void Main(string[] args)
        {
            var list1 = new List<DateItem>
            {
                new DateItem{Date = DateTime.UtcNow.AddDays(-2), Name = "The day before yesterday" },
                new DateItem{Date = DateTime.UtcNow.AddDays(1), Name = "Tomorrow" }
            };

            var list2 = new List<DateItem>
            {
                new DateItem{Date = DateTime.UtcNow.AddDays(2), Name = "The day after tomorrow" },
                new DateItem{Date = DateTime.UtcNow.AddDays(-1), Name = "Yesterday" },
                new DateItem{Date = DateTime.UtcNow, Name = "Today" }
        };

            var merged = list1.Union(list2).OrderByDescending(d => d.Date);

            foreach (var day in merged)
            {
                Console.WriteLine(day.Name);
            }
        }
    }

    class DateItem
    {
        public DateTime Date { get; set; }
        public string Name { get; set; }
    }

}

Union does not merge the second IEnumerable into the first one, but yields the content of the two IEnumerable one after another — LeBoucher, Sep 19 '19 at 17:30

Daniel · Accepted Answer · 2019-10-17T07:38:10.017

Thanks for your help, the most helpful solution I found to the problem is:- Sorting the list by a JS function that runs on the uploaded content.

here is the code:

var item = $(".sort-item").sort(function (a, b) {
                var Adate = $(a).attr("data-date");
                var Bdate = $(b).attr("data-date");
                var Atime = $(a).attr("data-time");
                var Btime = $(b).attr("data-time");
                if (Adate < Bdate) return 1;
                if (Adate > Bdate) return -1;
                if (Atime < Btime) return 1;
                if (Atime > Btime) return -1;
                return 0;
           });
           $(".timeline").prepend(item);

Compare two lists on razor and sort them by newest (both have created datetime)

2 Answers2