WPF *is* part of .NET. I'm assuming that by .Net you really mean Windows Forms ("winforms").
WPF requires a very different way of thinking about User Interface programming. A "straight conversion" from winforms is not simple.
There are plenty of good books on WPF, none of which I can think of right now.
In any case, the property of the WPF
object that most closely corresponds to the winforms
, and it is of type
WPF allows a Label to contain essentially anything
, including another UIElement (or UIElement structure), string, or ...