Question

The following throws exception.

The course object that is being passed to InsertOnSubmit is of type Course that is generated by Linq.

 public ActionResult Course(CourseViewModel c)
 {
    Course course = (Course) c; //CourseViewModel is derrived from Course
    SchedulerDataContext db = new SchedulerDataContext();
    db.Courses.InsertOnSubmit(course);  // <- this is where exception is thrown
    db.SubmitChanges();
 }

There are already questions about this here and here, however, I don’t understand their answer. Supposedly I’m not creating an object in time. Which object and what exactly needs to happen?

Answer 1

You need to create the Course object before you try to insert it.

Course course = new Course { ... set the properties .. };
SchedulerDataContext db = new SchedulerDataContext();
db.Courses.InsertOnSubmit(course);
db.SubmitChanges();