Dynamic Or Clause Linq

You can build a predicate incrementally.

Func<Pantient, bool> predicate = p => false;

if (User.IsInRole("Administrator"))
{
    var oldPredicate = predicate;
    predicate = p => oldPredicate(p) || p.AdministratorID == UserID;
}

if (User.IsInRole("Counselor"))
{
    var oldPredicate = predicate;
    predicate = p => oldPredicate(p) || p.CounselorID == UserID;
}


var query = db.Patients.Where(predicate);

would this work?

var query = Patients.Where(
    x => (User.IsInRole("Administrator") && x.AdministratorID == UserID)
      || (User.IsInRole("Counselor") && x.CounselorID == UserID)
      || (User.IsInRole("Physician") && x.PhysicianID == UserID)
    );

Just in case anyone else is looking a different solution i found linqkit very usefull and easy to use. So in your example the solution would be something like this:

var predicate = PredicateBuilder.New<Patients>(true);

if (User.IsInRole("Administrator"))
{
     predicate = predicate.Or(x => x.AdministratorID == UserID);
}

if (User.IsInRole("Counselor"))
{
     predicate  = predicate.Or(x => x.CounselorID == UserID);
}

if (User.IsInRole("Physician"))
{
     predicate  = predicate.Or(x => x.PhysicianID == UserID);
}

query = query.Where(predicate)