Bind (Populate) only previous month in ASP.Net DropDownList using C# and VB.Net

Hi Comunidadmexi..,

Please refer below sample.

HTML

<div>
    <asp:DropDownList runat="server" ID="ddlMonths">
        <asp:ListItem Text="[ === Select month === ]" Value=""></asp:ListItem>
    </asp:DropDownList>
</div>

Namespaces

C#

using System.Globalization;

VB.Net

Imports System.Globalization

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        var previousMonth = DateTime.Now.AddMonths(-1).Month;
        ddlMonths.Items.Clear();
        ddlMonths.Items.Insert(0, new ListItem { Text = "[ === Select month === ]", Value = "" });
        ddlMonths.Items.Insert(1, new ListItem { Text = DateTimeFormatInfo.CurrentInfo.GetMonthName(previousMonth), Value = previousMonth.ToString() });
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim previousMonth = DateTime.Now.AddMonths(-1).Month
        ddlMonths.Items.Clear()
        ddlMonths.Items.Insert(0, New ListItem With {
            .Text = "[ === Select month === ]",
            .Value = ""
        })
        ddlMonths.Items.Insert(1, New ListItem With {
            .Text = DateTimeFormatInfo.CurrentInfo.GetMonthName(previousMonth),
            .Value = previousMonth.ToString()
        })
    End If
End Sub

Screenshot