If I understand your question correctly, on the ItemDataBound event you
could do something like this:

       If e.Item.ItemType = ListItemType.EditItem Then

           'look for the ddlWeekDay dropdown
           Dim ddlWeekDay As DropDownList =
CType(e.Item.FindControl("ddlWeekDay"), DropDownList)

           'populate the dropdown values
           Dim mySortedList As New System.Collections.SortedList
           Dim Item As DictionaryEntry

           mySortedList("0") = "Sunday"
           mySortedList("1") = "Monday"
           mySortedList("2") = "Tuesday"
           mySortedList("3") = "Wednesday"

           For Each Item In mySortedList
               Dim newListItem As New ListItem
               newListItem.Text = Item.Value
               newListItem.Value = Item.Key
               ddlWeekDay.Items.Add(newListItem)
           Next

           'set the current value held in the database
           Dim currentWeekDay As String =
DataBinder.Eval(e.Item.DataItem, "WeekDay")
           Dim li As ListItem =
ddlWeekDay.Items.FindByValue(currentWeekDay.ToString())
           If Not (li Is Nothing) Then
               li.Selected = True
           End If

Hope this helps.
Kat