Controlling Property Setting Order

I have an issue where I have a widget that exposes a text property. The value of that text property is the text property of a label that is embedded in my widget. My problem is that, when the .ui file is moc'd, the generated calls for my widget to set that property come before the label is created, so the designer (and runtime version of the app) will crash. Is there some way to force the moc process to generate the property set call after the label has been generated?

No there is not. Your widget is supposed to be fully initialized in the constructor. You can also check inside the setter of your property whether the label is already alive and if not, do the initialization before setting the label's text.