private void FillStudentsList(Exam exam)
{
var allStudents = _getAllStudentsQueryHandler.Handle();
var enrolledStudents = exam.EnrollStudents(allStudents, out var isEnoughStudents);
if (!isEnoughStudents)
{
MessageBox.Show(this, "Not enough students for the exam", "Warning");
}
studentBindingSource.DataSource = enrolledStudents;
dgvEnrolledStudents.Refresh();
}