You can Select Value for Drop Down after Page Load Event
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
FillList();
Viewstate["id"] = Request.QueryString["id"];
if (Request.QueryString["id"] != null)
{
FillData();
div_General.Visible = true;
div_Special.Visible = true;
}
}
}
Now in Page_PreRender you can Select Value in dropdown like this:-
protected void Page_PreRender(object sender, EventArgs e)
{
if(!Page.IsPostBack)
{
if (ViewState["id"] != null)
{
dropdownlist1 .SelectedValue = ViewState["id"].ToString();
}
}
}
via Rahul om stackoverflow