ios - Unable to make outlet connection to a constraint in IB

Question

I am running XCode 5 with iOS 7. I need to dynamically change the height constraint of a UITextView prior to its layout. I have seen many postings stating that this can be done by making an outlet connection from the constraint in IB to the source code. I am trying to make the connection from the constraint outlet in IB to the header file of the owning class, but am unable to make the connection - IB does not "highlight" when I drag over the header file, as it does when making connections from other objects like buttons etc.

Has anyone encountered this before? All help is greatly appreciated.

Answer 1

Here is a picture of me doing it. I'm control-dragging from the constraint to the header file.

In real life I'm more likely to control-drag to the anonymous category in the implementation file, because I don't want an IBOutlet property to be public. So here's a picture of that too. Sorry, this screen shot does not show the cursor: it is at the bottom end of the stretch line.