Non-Databound DropDownList SelectedValue Problem

When you have an asp:DropDownList which is *not* databound, (i.e. you add the items manually) there are a few things you have to do to get 'SelectedValue' to work or you get: Error: 'DropDownList' has a SelectedValue which is invalid because it does not exist in the list of items. - Workaround from CraigW Blog.