I would recommend doing the first example, even though it might be more typing.
It has two distinct advantages:
The first being what Michael Liu stated, which is that the size of the ViewState is has more granularity. If you only use 2 of 10 properties, then your ViewState size only accounts for the 2 that you've actually assigned to.
The second which I feel like even more important is that this follows the same pattern of UserControls, in that they have properties that you assign to. For example, given a UserControl with a Text
property, using the user control in the ASPX would look like the following:
<demo:MyUserControl Text="Some Text" runat="server" />
Which will also work in the designer. So there's something to be said for following convention, that (for the most part) properties get persisted between post-backs.