How to access selected index of a DropDownList within a repeater asp/net c#

I all,

I've got the following code from a pervious example: -

        protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)           

        {
            int SelectedIndex = 0;
            var controls = Repeater1.Items.Cast<RepeaterItem>()
            .Where(t => t.ItemType == ListItemType.Item || t.ItemType == ListItemType.AlternatingItem)
            .Select(t => t.FindControl("cmbReturnStage"));

there is a control called cmbReturnStage that I need to set the selected index based on a variable ie: -

cmbReturnsStage.Selectedindex = varSelectedIndex;

How do I gain control over the DropDownList of the individual row in the repeater to set it's selectedIndex please?

Many Thanks
Lee