Keep Last Item in DropDownList as selected in ASP.Net

You need to select the data order by CityId in descending order. So that you your last inserted item will be the first element in the dropdownlist.

Page1

HTML

<asp:DropDownList ID="ddlCities" runat="server">
        </asp:DropDownList>
        <asp:HyperLink Text="Redirect to next page" NavigateUrl="~/Default2.aspx" runat="server" />

Namepaces

using System.Configuration;
using System.Data.SqlClient;
using System.Data;

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.PopulateCities();
    }
}

private void PopulateCities()
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection conn = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT * FROM Cities ORDER BY CityId DESC ", conn))
        {
            using (SqlDataAdapter da = new SqlDataAdapter(cmd))
            {
                DataSet ds = new DataSet();
                da.Fill(ds);
                ddlCities.DataValueField = "CityId";
                ddlCities.DataTextField = "CityName";
                ddlCities.DataSource = ds;
                ddlCities.DataBind();
            }
        }
    }
}

Second Page

HTML

<table border="0" cellpadding="0" cellspacing="0">
    <tr>
        <td>
            Enter City
        </td>
        <td>
            <asp:TextBox ID="txtCityName" runat="server" />
        </td>
    </tr>
    <tr>
        <td colspan="2">
            <asp:Button runat="server" Text="Save" OnClick="Save" />
        </td>
    </tr>
</table>
<asp:HyperLink ID="HyperLink1" Text="Redirect to previous page" NavigateUrl="~/Default.aspx" runat="server" />

C#

protected void Save(object sender, EventArgs e)
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    string sqlStatment = "INSERT INTO Cities VALUES(@CityName)";
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(sqlStatment, con))
        {
            cmd.Parameters.AddWithValue("@CityName", this.txtCityName.Text.Trim());
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
}