How do I bind an ASP.NET FormView to a single record?
As the error message says, the DataSource object must implement IListSource, IEnumerable or IDataSource to work.
If you have an object av type A which do not implement one of the mentioned interfaces then you could as you say wrap your object in a list:
C#
var myDataSource = new List<A> {myObject};
VB.NET
Dim myDataSource As List(Of A)(myObject)