Detect state change of model property, in controller, using Entity Framework

I have a more or less standard looking model:

public class Project {
  public int ID { get; set; }
  //... some more properties

  public DateTime StartDate { get; set; }
  public int Duration { get; set; }
}

If the user modifies StartDate or project Duration, I have to call a function to update a simulation. In order to achieve this I'd like to detect the state change of the fields StartDate and Duration within a controller.

Something like that:

if(project.StartDate.stateChange() || project.Duration.stateChange())

Here is an example of what the Controller Method would look like:

[HttpPost]
public ActionResult Edit(Project project)
{
    if (ModelState.IsValid)
    {
        if(project.StartDate.stateChange() || project.Duration.stateChange())
            doSomething();

        db.Entry(project).State = EntityState.Modified;
        db.SaveChanges();
        return RedirectToAction("Index");
    }
    return View(project);
}

Any idea, how can I achieve this?