Disable/remove value in dropdown menu after being selected

Question

Just wanna ask u guys for help. I have this dropdown menu in my abc.aspx page. There, user will choose month and enter the expenses and prices in the textbox provided. It will b

Answer 1

Why not try the following:

ASPX

<asp:DropDownList ID="DropDownList1" runat="server" Font-Bold="True" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
    <asp:ListItem Text="Please choose" Value=""></asp:ListItem>
    <asp:ListItem Text="January" Value="January"></asp:ListItem>
    <asp:ListItem Text="February" Value="February"></asp:ListItem>
    <asp:ListItem Text="March" Value="March"></asp:ListItem>
</asp:DropDownList>

C#

    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (Session["Month"] != null)
        {
            if (DropDownList1.SelectedValue == Session["Month"])
            {
                DropDownList1.SelectedValue = string.Empty;
            }
            else
            {
                Session["Month"] = DropDownList1.SelectedValue;
            }
        }
    }

Make this is the ASPX and C# on your first page.