ListBox lst = new ListBox();
lst.Items.Add(new ListItem("rupa"));
lst.Items.Add(new ListItem("anitha"));
lst.Items.Add(new ListItem("latha"));
lst.Items.Add(new ListItem("rani"));
That is what you looking for ?
Ok now as manfred suggested I can revise my answer like
string str = "hiren,manfred,you,me,all,cp";
string[] items = str.split(',');
for(int i=0;i<items.length;i++)>
{
lst.add(new ListItem(string[i]));
}