DropDownList and Update Panel

Question

I develop address control, which contains 2 DropDownLists (for cities and countries) and several TextBoxes. The second DropDownList DataSource depends on the first DropDownList

Answer 1

Move the code on Page_Init to Page_Load and put it inside !IsPostBack

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        ddlCountry.DataBind();
        ddlCity.DataSource = Facade.Addresses.GetCities(countryId);
        ddlCity.DataBind();
    }
}