private void save_task_button(object sender, RoutedEventArgs e) { if (NameOfTaskTB.Text == "" || TypeComboBox.Text == "" || DueDateOfTaskDP.SelectedDate == null || EndDateOfTaskDP.SelectedDate == null) { MessageBox.Show("Please enter all information"); } else { string taskName = NameOfTaskTB.Text; string type = Convert.ToString(TypeComboBox.Text); DateTime dueDate = (DateTime)DueDateOfTaskDP.SelectedDate; DateTime endDate = (DateTime)EndDateOfTaskDP.SelectedDate; FileReadWrite file = new FileReadWrite(); Task_ editTask = new Task_(taskName, type, reocurring, dueDate, endDate); student.TaskList[index] = editTask; file.EditTaskToFile(student, editTask, oldTask); homeScreen hs = new homeScreen(student); this.Close(); hs.Show(); } }