Question

I want a controller action “ProfessorStatus” which queries “Professor” table and returns list of active professors for a particular school.

Here is the controller action I have, I am struggling with parameterizing the “School” columns

 public ActionResult ProfessorStatus(string schoolType) 
    { 

        var activeProfessors = (from p in prof.ProfessorTable.Where(a => a.Engineering.Value == true) 
                              group p by p.ProfessorID into g 
                              select g.Key).ToList(); 

        return View(activeProfessors); 
    }

Now, In the above controller action. Instead of hard coding “Engineering” I want to parameterize it with “schoolType”.

So if I pass schoolType = Medicine Then the controller will display professors from medicine school and so on for other school types.

How can I avoid hardcording here? Thanks in advance.

Answer 1

If you are not in a position to redesign your whole database and the systems that use it, you can still get around this by using expressions.

public ActionResult ProfessorStatus(string schoolType) {
  Expresison<Func<Professor, bool>> filter;
  switch (schoolType) {
    case "Engineering":
      filter= a => a.Engineering.Value == true;
      break;
    default:
      throw new Exception("Unknown SchoolType - " + schoolType);
  }
  var activeProfessors = (from p in prof.ProfessorTable.Where(filter)
     group p by p.ProfessorID into g
     select g.Key).ToList();
  return View(activeProfessors);
}