Filter large list based on date time

Question

I have the following Items class:

public class Item
{
   public Item()
   {
   }

   public string Id {get; set;}
   public string Name {get; set;}
   public string Price {get; set;}
   public DateTime CreatedDate {get; set;}

}

and then in my code I have List<Item> items that contains A LOT of items of type Item, my question is what you recommend as the best way/practice of sorting/filtering the items in the list based on CreatedDate for the following scenarios:

• all items where the CreatedDate is before date x
• all items where the CreatedDate after date x
• all items where the CreatedDate between date x and date y

P.S. What about if I will mentione also the time? Like before/after/between date x time y ?

Answer 1

You can use LINQ:

var beforeDateX = items
    .Where(i => i.CreatedDate.Date < DateX); // remove the .Date if you want to include the time
var afterDateX = items
    .Where(i => i.CreatedDate.Date > DateX);
var betweenDates = items
    .Where(i => i.CreatedDate.Date >= DateX && i.CreatedDate.Date <= DateY);

You can use a foreach or methods like ToList to execute the query and materialize the result.

foreach(Item i in beforeDateX)
    Console.WriteLine("Name:{0} CreatedDate:{1}", i.Name, i.CreatedAt);

Answer 2

Use Linq:

var itemsBefore = items.Where(i => i.CreatedDate <= timeBefore);
var itemsAfter = items.Where(i => i.CreatedDate >= timeAfter);
var itemsBetween = items.Where(i => i.CreatedDate >= timeStart && i.CreatedDate <= timeEnd);

For ordering

var ordrered = items.OrderBy(i => i.CreatedDate);