Sorting a Listbox of dates in the form dd/mm/yyyy in C#

Question

I have a listbox and a (annual holiday) date picker. The user chooses the date and adds it to the Listbox. I then want to sort the Listbox from earliest to latest date. I tried using sorted Listbox but that did not work as it sorts like they are alphabetic strings. I then used unsorted Listbox and found some code and changed it to sort the box manually but again this is alphabetical. I am using the date as dd/mm/yyyy each date on a new line e.g.

If I have:

01/01/2023
02/12/2022
23/12/2022
24/12/2022

then I want the listbox to show me

02/12/2022
23/12/2022
24/12/2022
01/01/2023

what I get is the following where it sorts from left to right rather than year then month then day

01/01/2023
02/12/2022
23/12/2022
24/12/2022

At present I use the following code to add and then sort but there must be an easy way to sort this.

void Btn_add_holidayClick(object sender, EventArgs e)
        {
        lstbx_annual_hol.Items.Add(DatePick_Hol_Date.Value.Day.ToString("D2") + "/" +
                                       DatePick_Hol_Date.Value.Month.ToString("D2") + "/" +
                                       DatePick_Hol_Date.Value.Year.ToString() +"\n");  

            SortAnnualHoliday();
        }
        
        void SortAnnualHoliday()
        {
            ArrayList arList = new ArrayList(); 

            foreach (object obj in lstbx_annual_hol.Items)
            {
                arList.Add(obj);
            }
            
            arList.Sort(); 

            lstbx_annual_hol.Items.Clear();

            foreach(object obj in arList)
            {
                lstbx_annual_hol.Items.Add(obj); 
            }
        }
    

Thanks in advance for any advice and solutions even if you think I should do it a completely different way.

Answer 1

Create a List<DateTime> so that you can SORT it based on the dates within. You can use a BindingSource to attach the List to your ListBox, making it update whenever changes are made.

Something like:

public partial class Form2 : Form
{

    private List<DateTime> dates = new List<DateTime>();
    private BindingSource source = new BindingSource();

    public Form2()
    {
        InitializeComponent();
        source.DataSource = dates;
        lstbx_annual_hol.FormatString = "d";
        lstbx_annual_hol.DataSource = source;
    }

    private void Btn_add_holidayClick(object sender, EventArgs e)
    {
        dates.Add(DatePick_Hol_Date.Value);
        dates.Sort();
        source.ResetBindings(false);
    }

}