Datalist selected item

[Guest]

I want a certain item to be marked as selected when the datalist is created
for the first time the value of this item is taken from another page through
request.querystring

I think i need t find the ondex of this value or something like that
Is there is a way to do so

I need something like we do in ListItem control
listitem1.SelectedIndex =
listitem1.Items.IndexOf(lst.Items.FindByText(value));