Often times when you are using Entity Framework and trying to update objects using the handy
db.Entry(useableProperty).CurrentValues.SetValues(property);
Method you will encounter the error
InvalidOperationException: The property ‘PropertyID’ is part of the object’s key information and cannot be modified problem
After lots of thought I came across the remarkably simple answer, to wit – the PropertyID field is not being EXPLICITLY included in the object you are passing back to the controller. Just put that in a “HiddenFor and you’re all set.