Sorting months in ASP.Net DropDownList using C#

Hi theunclevince,

Use Linq OrderBy clause.

Refer below code.

HTML

<asp:DropDownList runat="server" ID="ddlyear">
    <asp:ListItem Text="2025" Value="2025" />
    <asp:ListItem Text="2024" Value="2024" />
</asp:DropDownList>
<br />
<asp:DropDownList runat="server" ID="ddlmonth">
</asp:DropDownList>

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        ddlmonth.Items.Clear();

        for (int month = 1; month <= 12; month++)
        {
            string monthName = DateTimeFormatInfo.CurrentInfo.GetMonthName(month).ToUpper();
            ddlmonth.Items.Add(new ListItem(monthName, month.ToString().PadLeft(2, '0')));
        }
        ddlmonth.Items.Insert(0, new ListItem("[== Selected ==]", ""));

        DateTime dateTime = DateTime.Now;
        List<ListItem> months = new List<ListItem>();

        if (ddlyear.SelectedValue == "2024")
        {
            for (int i = 12; i >= 6; i--)
            {
                months.Add(ddlmonth.Items[i]);
            }
        }
        else
        {
            for (int i = 1; i < DateTime.Now.Month; i++)
            {
                months.Add(ddlmonth.Items[i]);
                //months.Reverse();
            }
        }

        //Determines first item i.e.Equals Default Item.
        ListItem defaultItem = ddlmonth.Items[0];

        //Clears all items in the DropDownList.
        ddlmonth.Items.Clear();

        //Reverse the List of last two months.
        //months.Reverse();

        // Order by month name.
        months = months.OrderBy(x => x.Value).ToList();

        //Inserts Default Item.
        months.Insert(0, defaultItem);

        //Assigning month to DropDownList.
        ddlmonth.DataSource = months;
        ddlmonth.DataTextField = "Text";
        ddlmonth.DataValueField = "Value";
        ddlmonth.DataBind();
    }
}

Screenshot