when i select area from dropdown list it should display all attributes from the same table.

try this it works

{
        if (!IsPostBack)
        {
            // Declare objects

            // Read the connection string from Web.config
            string connectionString =
            ConfigurationManager.ConnectionStrings[
            ""].ConnectionString;
            // Initialize connection
            conn = new SqlConnection(connectionString);

            SqlCommand = new SqlCommand(
            "select delivery_charges,tax,shipping from delivery", conn);


            try
            {
                // Open the connection
                conn.Open();
                // Execute the command
                reader = SqlCommand.ExecuteReader();
                // Populate the list of area
                ddlplace.DataSource = reader;
                ddlplace.DataValueField = "area";
                ddlplace.DataTextField = "area";
                ddlplace.DataBind();
                // Close the reader
                reader.Close();
            }



            finally
            {
                // Close the connection
                conn.Close();
            }
        }
    }

public void area()
{
if (ddlplace.SelectedItem.Value == "yes")
{
if (con.State == ConnectionState.Closed)
{
con.Open();
}
SqlCommand cmd = new SqlCommand("select delivery_charges,tax,shipping from delivery ", con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
ddlplace.DataSource = dt;
ddlplace.DataTextField = "area";
ddlplace.DataValueField = "area";
ddlplace.DataBind();
con.Close();

}


The area named field not in the table add that and use this code