In an ArcMap extension, I need to flip multiple lines from a selection.
The ArcMap Flip button only allows you to flip one feature at a time.
What's the ArcObjects equivalent to ArcMap's Flip button?
ICurve.ReverseOrientation should do what you want.
Actually there is a full snippet Flip Line Direction Snippet , available in the ESRI online documentation.
Here is a small extract from it: