问题
I realised that my maps app was not connected to the new storyboard. I have tried everything (to my knowledge) and have just about run out of ideas.
And yes I have changed the class in the storyboard to the map controller that I am trying to connect it to.
回答1:
To connect objects to already existing outlets you need to mouseover the variable name instead of the gutter.
Like so:
回答2:
please check your class name in "show the identity inspector" panel as in following image.
来源：https://stackoverflow.com/questions/46270740/xcode-8-3-3-not-allowing-to-connect-iboutlet-to-the-storyboard