listbox

have 2 listboxes in my page in listbox1 some items are there if i select more than 1 item and click button those selected items added to listbox2 at the same time in listbox 1 those items shall be removed. I wrote the code as below int StateID = int.Parse(lst1.SelectedItem.value); obj.Admin_Delete_State(); DataSet ds = new DataSet(); ds = obj.Admin_Select_State(); for (int i = 0; i < lst1.Items.Count; i++) { if (lst1.Items[i].Selected) { lst1.Items.Remove(lst1.Items[i].Value); lst2.Items.Add(lst1.Items[i].Value); i--; } } here stateid is taking null value .how can i delete

plz help me
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